Startseite Synthesis, properties, and activity of MoVTeNbO catalysts modified by zirconia-pillared clays in oxidative dehydrogenation of ethane
Artikel Open Access

Synthesis, properties, and activity of MoVTeNbO catalysts modified by zirconia-pillared clays in oxidative dehydrogenation of ethane

  • Kamshat Abithanovna Shorayeva EMAIL logo , Bakytgul Kabykenovna Massalimova , Yulia Nikolaevna Bespalko , Evgenii Pavlovich Kovalev , Arcady Vladimirovich Ishchenko und Vladislav Aleksandrovich Sadykov
Veröffentlicht/Copyright: 26. April 2021

Abstract

Composites comprising MoVTeNbO mixed oxide and zirconia-pillared montmorillonite clays (PilCs) were prepared. XRD and TEM with EDX studies confirmed the preservation of M1 MoVTeNbO phase in these composites responsible for high activity and selectivity in ethane oxidative dehydrogenation into ethylene. For composites with PilC content of 10 wt%, the best ethylene yield exceeding that of bulk MoVTeNbO oxide was demonstrated for clays with zirconia pillars doped with Ce and Al possessing the highest specific surface area. This is explained by optimized chemical interaction of these clays with MoVTeNbO mixed oxide improving its bulk oxygen mobility and reactivity by structure disordering while blocking surface sites responsible for combustion due to the stabilization of the reactive terminal oxygen species.

1 Introduction

Oxidative dehydrogenation of ethane (ODE) is a perspective method for ethylene production, since this method allows the process to be carried out at relatively low temperatures with sufficiently high selectivity [1]. Currently, the most effective catalysts for this process are considered to be MoVTeNbO mixed oxides [2,3,4,5,6]. The active and selective phase of the MoVTeNbO catalyst denoted by M1 with the composition (AO)2−2x (A2O) x M20O56 (0 ≤ x ≤ 1, A = Te, Sb, and M = Mo, V, and Nb) has the orthorhombic structure [7]. Botella et al. [8] demonstrated successful design of MoVTeNbO catalyst with a high activity and selectivity in the ODE (80% ethylene selectivity at 340–400°C). However, attempts to increase activity and selectivity of these catalysts continue. Modifying cationic composition of the M1 phase does not lead to a significant increase in activity. In addition, MoVTeNb mixed oxides have a low specific surface area, which limits their potential opportunities for industrial application. Traditional approach to enhance the surface area of the catalysts is based on the use of supports with a high surface area, which allows to disperse the active component particles, thus increasing the surface to volume ratio and, therefore, the amount of accessible active sites on the surface. Using various supports like alumina, silica, TiO2, or Nb2O5 for preparation of high surface area MoVTeNbO-based catalysts failed since supporting appeared to strongly inhibit the crystallization of the M1 phase [9,10]. Nanocomposite oxide catalysts of the overall composition V0.3Mo1Te0.23Nb0.12/n SiO2 (n = 0, 10, 25, 35, and 50 wt%) were tested in ODE [11]. The catalyst with 10 wt% SiO2 content exhibits the highest specific (per gram) activity due to the presence of nanodomains of the M1 phase. This implies that a promising approach to enhance the performance of these mixed oxide catalysts could be based on adding a moderate amount of promoters with a high dispersion, thus forming nanocomposites with improved textural characteristics. At higher SiO2 content, the activity declines due to the segregation of amorphous SiO2 layers on the catalysts surface. To deal with this problem, Bondareva et al. [12] prepared MoVTeNbO composites with Al–Si–O oxide (SiO2 content 5 wt%) with a support content up to 70%. Again, the highest activity and ethylene selectivity were observed for the catalyst with the additive content of 10 wt% due to the formation of mixed Al-containing phases at a higher support content. Hence, more chemically stable high surface area supports are apparently required to provide a higher dispersion of MoVTeNbO oxide without deteriorating its performance.

Pillared clays containing in their interlayer space ZrO2, CeO2, La2O3, and other oxide nanoparticles are promising as supports for catalysts of different catalytic processes. These materials possess a high thermal stability and a developed pore structure comprising micropores (corresponding to galleries between aluminosilicate layers) and mesopores (generated due to faults in the clay sheets’ stacking). Besides, clays constitute good and cheap supports to achieve high dispersion of metal oxide species [1317].

In this article, we describe the characterization and catalytic performance in ODE of nanocomposites comprising Mo–V–Nb–Te mixed oxides with zirconia-pillared clays (Zr-PilCs) synthesized using natural clays of Kazakhstan’s fields [1416]. Features of interaction between the components during the catalyst preparation affecting their texture, structural features, and reactivity were elucidated by N2 adsorption, XRD, and HRTEM with EDX. Since for composites with PilCs, the best performance was also revealed with additive content of 10 wt%, and the main attention was devoted to the elucidating effect of cations modifying zirconia nanopillars at PilC preparation, and, hence, their textural features, on the composite’s characteristics and catalytic properties at this fixed content of PilCs.

2 Methods

2.1 PilC preparation

Synthesis of PilCs samples has been carried out using a montmorillonite (MM) clay, where initial CaO and MgO contents are of ∼2 wt% and Fe2O3 admixture content is of 4.4 wt% (Table 1) according to the optimized procedures of pillaring with Zr–O polynuclear species doped with Ce, Ca, Al, and Ba cations described in details elsewhere [1416]. Zr-containing solutions (Zr concentration 0.2 M) were prepared from recrystallized ZrOCl2·8H2O (Vekton, Russia) and zirconium acetate (solution in diluted acetic acid; Aldrich, Germany). After the pillaring and washing procedures, the obtained PilC was dried for 24 h at room temperature and then calcined at 500°C for 5 h.

Table 1

Elemental analysis of the initial sample of montmorillonite

Sample Content, wt%
SiO2 Al2O3 Fe2O3 TiO2 CaO MgO SO3 K2O Na2O Others
Initial clay 55.5 19.38 4.4 0.3 1.98 2.18 0.2 0.5 0.14 11.3

2.2 Catalyst preparation

The oxide catalysts of the atomic composition V:Mo:Te:Nb = 0.3:1:0.23:0.12 were synthesized by the procedure described in [18] for the bulk samples. The starting chemicals were ammonium molybdate (NH4)6Mo7O24·4H2O (Vekton, Russia), ammonium metavanadate NH4VO3 (Reakhim, Russia), telluric acid H6TeO6 (Alfa Aesar, Germany), and niobium oxalate solution (C2O4 2–/Nb = 3.0) freshly prepared by mixing a precipitated niobium hydroxide in an oxalic acid solution. Niobium hydroxide was obtained by the precipitation of NbCl5 (Acros Organics) with an aqueous solution of ammonia (Acros) at pH 7. The main substance content of the chemicals was higher than 99%. To a VMoTe solution prepared by dissolving the starting compounds, a solution of niobium oxalate and nitric acid was added in succession providing pH 3. To prepare bulk mixed oxide, this solution was fast dried using a laboratory dryer (BUCHI B-29, Germany) with an inlet temperature of 220°C and an outlet temperature of 110°C, then pelletized followed by crushing and milling of pellets, and the 0.25–0.5 mm fraction was separated by sieving. It was then subjected to a short heat treatment at 310°C in air and calcined in the He flow at 550°C for 2 h.

The MoVTeNbO/PILC catalysts were prepared by adding the necessary amount of PilCs (mainly 10 wt% as related to oxide) into the mixed solution described above. The obtained composites were subjected to the same thermal procedures described above for the bulk sample.

2.3 Characterization

Structural and textural properties of materials were studied by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) with elemental analysis (EDX), and N2 adsorption. For XRD studies, a D8 Advance (Bruker, Germany) diffractometer with Cu-Kα radiation and LynxEye position sensitive detector was used (2θ range 20–85°, step size 0.05, and accumulation time 3 s).

For HRTEM studies, a JEM-2200FS (JEOL Ltd., Japan; acceleration voltage 200 kV, lattice resolution 1 Å, and Cs-corrector) equipped with an EDX spectrometer (JEOL Ltd., Japan) and a JEM-2010 (JEOL Ltd.; accelerating voltage 200 kV, lattice resolution 1.4 Å) instruments were used. Samples for these studies were prepared by ultrasonic dispersing in ethanol followed by suspension deposition onto a holey carbon film located on a copper grid.

In textural studies, N2 adsorption isotherms [−196°C, an ASAP-2400 (Micromeritics, USA)] were obtained for samples pretreated in vacuum (150°C, 16 h). T-plot analysis was used to determine the micropore volume and the average pore size was estimated as 4 V/A. The four-point Brunnauer-Emmet-Teller (BET) method (a SORBI N.4.1 apparatus, samples pretreatment in vacuum at 200°C for 1 h) was used to determine their specific surface area.

Temperature-programmed reduction by hydrogen (H2-TPR) was carried out in a flow installation (10 vol% H2 in Ar, flow rate 40 mL/min) [19].

2.4 Catalytic reaction

The catalytic properties were investigated in a setup with online chromatographic analysis of the reaction mixture components described in [11,12,18,19]. Experiments were carried out at atmospheric pressure in a tubular reactor with coaxially located thermocouple pocket in a fixed bed of the catalyst. The feed composition was C2H6:O2:N2 = 10:10:80 (vol%) with the reaction T of 400–470°C and GHSV of 600–2,400 h−1. The catalyst fraction was 0.25–0.50 mm. Controlled experiment conducted at 480°C confirmed the absence of transformations of both ethane and oxygen in empty reactor without catalyst.

  1. Ethical approval: The conducted research is not related to either human or animal use.

3 Results and discussion

3.1 Textural properties

Table 2 presents the textural characteristics of PilCs used for synthesis of composites. Both specific surface area and pore volume vary substantially depending upon the nature of the pillaring species but micropore share being negligible. This is determined by the effect of the composition and aging conditions of pillaring species on their shape and size as considered in original publications [1416]. Smaller size of pillaring species results in smaller pore size (distance between alumosilicate layers) and larger values of specific surface area.

Table 2

Textural characteristics of pillared clays

No. Abbreviation, type, and content of pillars S BET, m2/g V pores cm³/g V micropore cm³/g Average pore diameter, Å D pores, Å
1 Montmorillonite clay (MM) 54 0.12 0.002 95 139
2 Zr–Ba-pillared MM, 20 wt% ZrO2 + 0.2% Ba 100 0.20 0 86 138
3 Al-pillared MM, 4.0 wt% Al 40 0.17 0 176 204
4 Zr–Ca-pillared MM, 20 wt% ZrO2 + 0.2 wt% Ca 67 0.12 0 77 128
5 Zr–Ce-pillared MM, 20 wt% ZrO2 + 0.06 wt% Ce 217 0.06 0 24 106
6 Zr–Al-pillared MM, 20 wt% ZrO2 + 4.8 wt% Al 230 0.07 0.060 26 95

Table 3 presents information about specific surface area of bulk VMoTeNbO catalyst and composites with 10 wt% of PilCs. In agreement with earlier obtained results of adding close amounts of silica and Al–Si–O to this mixed oxide [11,12], specific surface area increases only slightly for composites with this content of PilC. Apparently at a high content of added PilCs, the specific surface area of composites will also increase following earlier observed trends [11,12]: up to 20–30 m2/g at additive content of up to 50 wt%.

Table 3

Specific surface area of catalysts

Sample S sp., m2/g
Bulk MoVTeNbO 5.0
MoVTeNbO + Zr–Ce-PilC 5.7
MoVTeNbO + Zr–Al-PilC 6.1

3.2 Structural characteristics

According to the X-ray data (Figure 1), the main phase of PilCs is disordered dehydrated montmorillonite. For all samples after calcination at 500°C, the interlayer (001) reflex situated for pure montmorillonite at ∼5° is not observed due to disordering by the intercalated zirconia nanoparticles. In addition to the main phase of MM (PDF 00-001-0026), reflections of quartz (a natural admixture in montmorillonite) and zirconium oxide of monoclinic and tetragonal modification (related to aggregated pillaring species) are also observed.

Figure 1 
                  Diffraction patterns of Zr–Ce-, Zr–Ca-, and Zr–Al-pillared clays.
Figure 1

Diffraction patterns of Zr–Ce-, Zr–Ca-, and Zr–Al-pillared clays.

Figure 2 presents the diffraction patterns of bulk VMoTeNbO oxide and its composites with 10 wt% of Zr–Ce- or Zr–Al-PilCs. MoVTeNbO catalyst is rather a pure M1 phase (active component in oxidative dehydrogenation of alkanes) [28,18] with a minor admixture of M2 phase. Its diffraction pattern is in good agreement with the calculated X-ray pattern for the M1 phase presented in [20]. For these composites, the phase composition of VMoTeNbO oxide is the same as that of pure bulk oxide comprising the mixture of M1 phase and M2 phase in ∼9:1 ratio. In the diffraction patterns of composites, peaks corresponding to M1 phase (PDF 00-058-0789) and M2 phase (PDF 00-057-1099) are identical to those in MoVTeNbO prototype [4,6]. No other impurity phases were observed, which shows that the prepared complex oxides exhibit high M1 phase purity. Main reflections corresponding to the montmorillonite phase are absent, which agrees with a small amount of added PilCs. Hence, the addition of PilCs to mixed MoVTeNbO oxide has not resulted in its destruction or modification of its phase composition.

Figure 2 
                  Diffraction patterns of bulk VMoTeNbO and its composites with 10 wt% of Zr–Ce- or Zr–Al-pillared clays.
Figure 2

Diffraction patterns of bulk VMoTeNbO and its composites with 10 wt% of Zr–Ce- or Zr–Al-pillared clays.

According to the XRD data (Figure 3), the structure of M1 and M2 phases in composites is maintained after catalytic investigations. Other oxide V-Mo phases were not detected.

Figure 3 
                  Diffraction patterns of bulk VMoTeNbO and its composites with 10 wt% of Zr–Ce- or Zr–Al-pillared clays after catalytic tests.
Figure 3

Diffraction patterns of bulk VMoTeNbO and its composites with 10 wt% of Zr–Ce- or Zr–Al-pillared clays after catalytic tests.

Figures 47 present the results of high-resolution TEM studies of bulk MoVTeNbO oxide and its composite with 10 wt% of Zr–Ce-PilC before and after testing in reaction. For bulk oxide before and after reaction point microdiffraction data confirmed the coexistence of regions corresponding to orthorhombic M1 phase (TeO) M5O14 (M = Mo, V, and Nb) with Pba2 space group (Figures 4c, 5b, and c) and pseudo hexagonal M2 phase (Figure 4b) (TeO) M3O9 (M = Mo, V, and Nb) with Pmm2 space group [2,4,6,20]. Moreover, domains of Mo–V–O [(Mo0.3V0.7)2O5 (PDF#21-576) and V0.95Mo0.97O5 (PDF#77-649)] are observed as well (Figure 4d).

Figure 4 
                  TEM image morphology (a), HRTEM and FFT images with labeled observed interplanar distances and corresponding indexes for phases M2 (b), M1 (c), and Mo–V–O (d) of MoVTeNbO catalyst before reaction.
Figure 4

TEM image morphology (a), HRTEM and FFT images with labeled observed interplanar distances and corresponding indexes for phases M2 (b), M1 (c), and Mo–V–O (d) of MoVTeNbO catalyst before reaction.

Figure 5 
                  TEM image morphology (a), HRTEM and FFT images with labeled observed interplanar distances and corresponding indexes for phases M1 (b and c) and Mo–V–O (d) of MoVTeNbO catalyst after reaction.
Figure 5

TEM image morphology (a), HRTEM and FFT images with labeled observed interplanar distances and corresponding indexes for phases M1 (b and c) and Mo–V–O (d) of MoVTeNbO catalyst after reaction.

Figure 6 
                  TEM images and EDX data for MoVTeNbO + Zr–Ce-PilC catalyst before reaction. (a) general morphology and (b–d) selected areas for elemental analysis.
Figure 6

TEM images and EDX data for MoVTeNbO + Zr–Ce-PilC catalyst before reaction. (a) general morphology and (b–d) selected areas for elemental analysis.

Figure 7 
                  TEM images and EDX data for MoVTeNbO + Zr–Ce-PilC catalyst after reaction. (a) General morphology and (b–d) selected areas for elemental analysis.
Figure 7

TEM images and EDX data for MoVTeNbO + Zr–Ce-PilC catalyst after reaction. (a) General morphology and (b–d) selected areas for elemental analysis.

For MoVTeNbO catalyst, after reaction (Figure 5) the particles’ morphology and crystallinity remain unchanged.

For composite catalysts, the most important feature is that in some regions, the surface layer is enriched by either Si or Al cations (Figures 6b and 7c) apparently leached from particles of PilCs at the stage of evaporation of their suspension in strongly acidic solution. Moreover, in Figure 6b a region comprising stacked amorphous silica nanoparticles with MoVTeNbO clusters was observed, resembling similar features revealed for composites with a high silica content [11]. Since particles of PilCs were not observed in all cases, this implies that in strongly acidic solution at the stage of evaporation, the PilCs could be completely disintegrated into nanosheets of silica and clusters of zirconia while all other cations were transferred into solution incorporating into the surface layers/bulk of MoVTeNbO particles after calcinations.

Figure 7 presents TEM images and EDX data for MoVTeNbO + Zr–Ce-PilC catalyst after reaction. As follows from these data, main structural features of catalyst remained unchanged after reaction.

3.3 Samples reactivity by H2-TPR

As follows from H2-TPR curves shown in Figure 8, for both composites with 10 wt% of Zr–Ce or Zr–Al, the PilCs reduction peaks are shifted to lower temperatures as compared with bulk oxide, while amounts of removed oxygen increase as well (Table 3), thus demonstrating increase in complex oxide reactivity due to the incorporation of PilC. By position, these TPR peaks correspond to the removal of strongly bound surface/lattice oxygen species [6]. In addition, the appearance of new peaks in the high temperature range 763 and 844°C implies much stronger interaction of catalyst cations with nanosized zirconia and silica particles and, hence, much higher oxygen bonding strength. Note that for PilCs, reactivity is much lower (see inset in Figure 8) as expected, so their share could not be revealed at all. Hence, the increase in reactivity can only be explained by disordering of MoVTeNbO particles in composites due to incorporation of cations leached from Zr-PilC, thus generating point and extended defects, which facilitate oxygen migration from the bulk. Note that for M1 phase comprising nanoparticles high-temperature H2-TPR peaks were not observed at all [6]. Such disordering can also increase surface reactivity of composites. Very important point is that for composites, any new low-temperature peaks have not appeared, hence, weakly bound reactive oxygen forms, which could be responsible for ethane and ethylene combustion, have not emerged (Table 4).

Figure 8 
                  H2-TPR curves for bulk PilC, MoVTeNbO oxide, and its composites with 10 wt% of pillared clays.
Figure 8

H2-TPR curves for bulk PilC, MoVTeNbO oxide, and its composites with 10 wt% of pillared clays.

Table 4

Characteristics of H2-TPR spectra

No Sample The maxima of peaks, °C H2 consumption, mol H2 g−1
T 1 T 2 T 3
1 MoVTeNbO 555 850 0.013
2 MoVTeNbO + 10 wt% Zr–Ce-PilC 549 857 0.016
3 MoVTeNbO + 10 wt% Zr–Al-PilC 532 763 844 0.017

3.4 Catalytic properties

To check the effect of the PilC content in composite on its catalytic properties, for Al-PilC additive (selected as the most neutral one), its content was varied from 7 to 25 wt%. As follows from Figure S1, the increase in additive content has resulted in decrease in activity, while ethylene selectivity varied only slightly, following earlier obtained trends for such additives as SiO2 and Al–Si–O [11,12]. Hence, in a similar way, it can be explained by blocking the surface sites of M1 phase particles by amorphous Al–Si–O clusters/layers and/or by the formation of aluminum molybdate Al2(MoO4)3 clusters destroying the surface planes of active M1 phase. This demonstrates that for PilCs as additives, the problem of strong interaction with MoVTeNbO oxide revealed by TEM with EDX remains crucial, which justifies our selection for studies of composites with fixed additive level of 10 wt%.

For studied samples’ data on dependence of ethane conversion and ethylene/CO x selectivity on contact time and temperature are provided in Table S1. Figure 9 compares the results for bulk MoVTeNbO oxide and the most active and the least active composites.

Figure 9 
                  Comparison of C2H6 conversion (a) and ethylene selectivity (b) dependence on temperature at contact time  5.52 s for bulk MoVTeNbO oxide and its composites with 10 wt% of Zr–Ce-, Zr–Al-, and Zr–Ca-PilCs.
Figure 9

Comparison of C2H6 conversion (a) and ethylene selectivity (b) dependence on temperature at contact time 5.52 s for bulk MoVTeNbO oxide and its composites with 10 wt% of Zr–Ce-, Zr–Al-, and Zr–Ca-PilCs.

Comparison with the textural characteristics (Table 2) shows that the most active composites have PilC additives with the highest specific surface area. This implies that the most important factor determining composites’ catalytic performance could be chemical interaction between their components at the preparation stage, which apparently proceeds easier for dopants with a higher specific surface area. Note that for the most active composites, ethane conversions practically coincide with those for bulk MoVTeNbO oxide (Figure 9a). In this case, three effects of doping appear to compensate each other – while surface disordering due to doping increases its reactivity (Figure 8), and specific surface area increases with doping as well (Table 3); some blocking of surface sites by nonreactive Zr–O and Al–O complexes could occur. As a result, ethane conversion could not be changed by doping with 10 wt% of Zr–Ce- and Zr–Al-PilC. For catalysts doped with Zr–Ca or Zr–Ba PilC, a lower activity (Table S1, Figure 9a) can be explained by partial blocking of surface sites by segregated nonreducible Ca and Ba cations as well as by carbonates bound with them. For these least active composites, a higher ethylene selectivity in all studied temperature range correlates with lower ethane conversions (Table S1, Figure 9). Note that for the case of pure montmorillonite as dopant (Table S1), ethane conversion and ethylene selectivity are also lower than for pure MoVTeNbO oxide being close to those for catalysts doped with Zr–Ca- or Zr–Ba-PilC. Since pure montmorillonite contains ∼2 wt% CaO as well as ∼2 wt% MgO (Table 1), this negative effect of doping can also be explained by the negative effect of the surface site blocking by carbonates bound with these basic cations, which are apparently stable in the studied moderate temperature range. In the case of Zr–Ce- and Zr–Al-PilCs, more acidic Zr, Ce, and Al cations could not stabilize carbonates in this temperature range, so their effect on blocking surface sites is not so substantial.

On the other hand, ethylene selectivity was somewhat improved due to doping with Zr–Al-PilC (Figure S2), which can be explained by some decrease in the surface coverage by the terminal oxygen species responsible for ethylene combustion. Moreover, for samples doped with Zr–Ce- and Zr–Al-PilC, ethylene selectivity also tends to be higher than that for undoped sample at temperatures >400°C (Figure 9), providing a higher ethylene yield, which is important for practice. Hence, a higher reactivity of these composites revealed by H2-TPR has not resulted in a lower ethylene selectivity. Since ethylene deep oxidation is related to more reactive terminal Me–O oxygen species [21,22], it implies that incorporation of Ce, Zr, and Al cations into the surface layer of M1 particles has not resulted in the generation of such species, which agrees with the absence of any new low-temperature H2-TPR peaks (Figure 8). Moreover, these cations could block surface sites on the faces of M1 phase, where oxygen adsorption in reaction conditions generates terminal M–O oxygen species.

As follows from Figure S2, at 400°C the dependence of ethylene selectivity on ethane conversion for doped samples excluding only that doped with Zr–Al-PilC is fitted by the same line. Although for the latter sample, the difference with other samples is not big, it appears to correlate with slightly higher reactivity and amount of oxygen removed in H2-TPR (Table 3). Since Al cations are contained both in pillars and in alumosilicate clay layers, their surface content in doped MoVTeNbO samples revealed by EDX (Figures 6 and 7) is higher than that of Zr and Ce, so they are expected to play a substantial role in the surface disordering. Note that addition of up to 25 wt% of Al–Si–O support to MoVTeNbO oxide has not affected the dependence of ethylene selectivity on ethane conversion at all [12]. This apparently demonstrates specificity of interaction of MoVTeNbO oxide with Zr-PilCs.

From the fundamental point of view, identical temperature dependencies of ethane conversion and ethylene selectivity for composites with Zr–Ce and Zr–Al PilC additives (Figure 9) imply the absence of any synergetic action of Ce cation able to change its oxidation stage, which can be explained by a complex composition, structure, and redox properties of M1 MoVTeNbO oxide phase determining its high performance in the studied reaction [112,21,22]. Hence, the increase of the specific surface area, generation of point and extended defects due to incorporation of Zr, Ce, and Al cations onto MoVTeNbO lattice, some surface structure disordering and blocking of sites able to retain terminal oxygen forms responsible for combustion appear to provide a better performance of catalysts doped with Zr–Ce and Zr–Al PilC. Detailed characterization of the defect and surface structure of these nanocomposites by applying modern spectroscopic methods is outside the scope of this article and could be the subject of the future studies.

From the practical point of view, the best composites of MoVTeNbO oxide with PilCs provide at 400°C ethane conversion and ethylene selectivity close to those of the best composites with SiO2 and Al–Si–O additives having close specific surface areas as well [11,12]. To achieve a higher performance of composites with PilC additives, the content of additives is to be increased while keeping chemical interaction between components at optimized level. It might be achieved by varying preparation conditions and adding PilCs not directly into the mixed acid solution of salts but to products of their evaporation ultrasonically dispersed in some solvents or subjected to hydrothermal treatment [10], which is certainly the subject of the future studies.

4 Conclusion

Composites comprising MoVTeNbO mixed oxide and zirconia-pillared montmorillonite clay additives were prepared by a simple procedure of evaporation of clay suspension in mixed salt solution followed by calcination. XRD and TEM with EDX studies confirmed the preservation of M1 phase in these composites responsible for high activity and selectivity in ethane oxidative dehydrogenation to ethylene despite strong chemical interaction between the components. The best catalytic properties (ethane conversion being equal to that for undoped MoVTeNbO oxide with a higher ethylene selectivity) were demonstrated for composites with additive content of 10 wt% and zirconia pillars doped with Ce and Al. This is explained by optimized chemical interaction of additives with MoVTeNbO mixed oxide, improving its bulk oxygen mobility and reactivity by some structure disordering and blocking surface sites stabilizing terminal M-O oxygen species responsible for combustion.

Acknowledgments

The research was done using equipment of Shared Knowledge Center “National Center of Catalyst Research” (Boreskov Institute of Catalysis SB RAS).

  1. Funding information: This work was supported by the Ministry of Science and Higher Education of the Russian Federation within the governmental order for Boreskov Institute of Catalysis (project AAAA-A21-121011390054-1) as well as by M. Kh. Dulaty Taraz Regional University, Taraz, Kazakhstan.

  2. Author contributions: K. S. was involved in investigation and writing; B. M. contributed to conceptualization; Y. B. was in charge of reviewing and editing and also methodology; E. K . and A. I. contributed to investigation; and V. S. was in charge of supervision.

  3. Conflict of interest: Vladislav Sadykov, who is the coauthor of this article, is the current editorial board member of Open Chemistry. This fact did not affect the peer-review process. The authors declare no other conflict of interest.

  4. Data availability statement: All data generated or analyzed during this study are included in this published article and its supplementary information files.

References

[1] Cavani F, Ballarini N, Cericola A. Oxidative dehydrogenation of ethane and propane: how far from commercial implementation. Catal Today. 2007;127:113–31. 10.1016/j.cattod.2007.05.009.Suche in Google Scholar

[2] Botella P, García-González E, López Nieto JM, González-Calbet JM. MoVTeNbO multifunctional catalysts: correlation between constituent crystalline phases and catalytic performance. Solid State Sci. 2005;7:507–19. 10.1016/j.solidstatesciences.2005.01.012.Suche in Google Scholar

[3] Ishchenko EV, Gulyaev RV, Kardash TY, Ishchenko AV, Gerasimov EY, Sobolev VI, et al. Effect of Bi on catalytic performance and stability of MoVTeNbO catalysts in oxidative dehydrogenation of ethane. Appl Catal A Gen. 2017;534:58–69. 10.1016/j.apcata.2017.01.023.Suche in Google Scholar

[4] Valente SJ, Armendáriz-Herrera H, Quintana-Solórzano R, del Ángel P, Nava N, Massó A, et al. Chemical, structural, and morphological changes of a MoVTeNb catalyst during oxidative dehydrogenation of ethane. ACS Catal. 2014;4:1292–301. 10.1021/cs500143j.Suche in Google Scholar

[5] Heracleous E, Lemonidou AA. Ni-Nb-O mixed oxides as highly active and selective catalysts for ethene production via ethane oxidative dehydrogenation. Part II: mechanistic aspects and kinetic modeling. J Catal. 2006;237:175–89. 10.1016/j.jcat.2005.11.003.Suche in Google Scholar

[6] Chu B, An H, Chen X, Cheng Y. Phase-pure M1 MoVNbTeOx catalysts with tunable particle size for oxidative dehydrogenation of ethane. Appl Catal A Gen. 2016;524:56–65. 10.1016/j.apcata.2016.05.026.Suche in Google Scholar

[7] Tsuji H, Koyasu Y. Synthesis of MoVNbTe(Sb)Ox composite oxide catalysts via reduction of polyoxometalates in an aqueous medium. J Am Chem Soc. 2002;124:5608–9. 10.1021/ja0122344.Suche in Google Scholar PubMed

[8] Botella P, García-González E, Dejoz A, López Nieto JM, Vázquez MI, González-Calbet J. Selective oxidative dehydrogenation of ethane on MoVTeNbO mixed metal oxide catalysts. J Catal. 2004;225:428–38. 10.1016/j.jcat.2004.04.024.Suche in Google Scholar

[9] Solsona B, Vázquez MI, Ivars F, Dejoz A, Concepción P, López Nieto JM. Selective oxidation of propane and ethane on diluted Mo-V-Nb-Te mixed-oxide catalysts. J Catal. 2007;252:271–80. 10.1016/j.jcat.2007.09.019.Suche in Google Scholar

[10] Nguyen TT, Aouine M, Millet JM. Optimizing the efficiency of MoVTeNbO catalysts for ethane oxidative dehydrogenation to ethylene. Catal Commun. 2012;21:22–6. 10.1016/j.catcom.2012.01.026.Suche in Google Scholar

[11] Bondareva VM, Ishchenko EV, Kardash TY, Ishchenko AV, Sobolev VI. Effect of SiO2 on the physicochemical and catalytic properties of VMoTeNbO catalyst in oxidative conversion of ethane. Russ J Appl Chem. 2016;89:1279–85. 10.1134/S1070427216080103.Suche in Google Scholar

[12] Bondareva VM, Ishchenko EV, Kardash TY, Ishchenko AV, Zenkovets GA, Tropin VI, et al. Ethane oxidative dehydrogenation on VMoTeNbO/Al–Si–O catalysts: effect of support on physicochemical and catalytic properties. Russ J Appl Chem. 2017;90:927–34. 10.1134/S1070427217070175.Suche in Google Scholar

[13] Benn Chaabene S, Bergaoui L, Ghorbel A, Lambert JF, Grange P. Acidic properties of a clay prepared from the reaction of zirconyl chloride solution containing sulfate ions with montmorillonite. Appl Catal A Gen. 2003;252:411–9. 10.1016/S0926-860X(03)00491-5.Suche in Google Scholar

[14] Sadykov VA, Kuznetsova TG, Doronin VP, Moroz EM, Ziuzin DA, Kochubei DI, et al. Molecular design and characterization of catalysts for NOx selective reduction by hydrocarbons in the oxygen excess based upon ultramicroporous zirconia pillared clays. Top Catal. 2005;32:29–38. 10.1007/s11244-005-9257-0.Suche in Google Scholar

[15] Sadykov VA, Kuznetsova TG, Doronin VP, Sorokina TP, Alikina GM, Kochubei DI, et al. Zirconia pillared clays: synthesis, characterization and catalytic properties in the NOx selective reduction by hydrocarbons in the oxygen excess. Chem Sustain Dev. 2003;11:249–62.Suche in Google Scholar

[16] Kuznetsova TG, Sadykov VA, Sorokina TP, Doronin VP, Alikina GM, Bunina RV, et al. Catalyst and method of removing nitrogen oxides from emission gases (options), Patent on invention RU 2194573 C1; September 17, 2001.Suche in Google Scholar

[17] Vicente MA, Belver C, Trujillano R, Bañares-Muñoz MA, Rives, Korili SA, et al. Preparation and characterisation of vanadium catalysts supported over alumina-pillared clays. Catal Today. 2003;78:181–90. 10.1016/S0920-5861(02)00328-0.Suche in Google Scholar

[18] Ishchenko EV, Andrushkevich TV, Popova GY, Chesalov YA, Plyasova LM, Ishchenko AV, et al. Effect of preparation conditions on the phase composition of the MoVTe(Nb) oxide catalyst for the oxidative conversions of propane. Catal Ind. 2010;2:291–8. 10.1134/S207005041004001X.Suche in Google Scholar

[19] Simonov M, Bespalko Y, Smal E, Valeev K, Fedorova V, Krieger T, et al. Nickel‐containing ceria‐zirconia doped with Ti and Nb. Effect of support composition and preparation method on catalytic activity in methane dry reforming. Nanomaterials. 2020;10(7):1–19. 10.3390/nano10071281.Suche in Google Scholar PubMed PubMed Central

[20] Ishchenko EV, Kardash TY, Gulyaev RV, Ishchenko AV, Sobolev VI, Bondareva VM. Effect of K and Bi doping on the M1 phase in MoVTeNbO catalysts for ethane oxidative conversion to ethylene. Appl Catal A Gen. 2016;514:1–13. 10.1016/j.apcata.2015.12.018.Suche in Google Scholar

[21] Grant JT, Venegas JM, McDermott WP, Hermans I. Aerobic oxidations of light alkanes over solid metal oxide catalysts. Chem Rev. 2018;118:2769–815. 10.1021/acs.chemrev.7b00236.Suche in Google Scholar PubMed

[22] Donaubauer PJ, Melzer DM, Wanninger K, Mestl G, Sanchez-Sanchez M, Lercher JA, et al. Intrinsic kinetic model for oxidative dehydrogenation of ethane over MoVTeNb mixed metal oxides: a mechanistic approach. Chem Eng J. 2020;383:123195. 10.1016/j.cej.2019.123195.Suche in Google Scholar

Received: 2020-08-05
Revised: 2021-02-28
Accepted: 2021-03-09
Published Online: 2021-04-26

© 2021 Kamshat Abithanovna Shorayeva et al., published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

Artikel in diesem Heft

  1. Regular Articles
  2. Qualitative and semi-quantitative assessment of anthocyanins in Tibetan hulless barley from different geographical locations by UPLC-QTOF-MS and their antioxidant capacities
  3. Effect of sodium chloride on the expression of genes involved in the salt tolerance of Bacillus sp. strain “SX4” isolated from salinized greenhouse soil
  4. GC-MS analysis of mango stem bark extracts (Mangifera indica L.), Haden variety. Possible contribution of volatile compounds to its health effects
  5. Influence of nanoscale-modified apatite-type calcium phosphates on the biofilm formation by pathogenic microorganisms
  6. Removal of paracetamol from aqueous solution by containment composites
  7. Investigating a human pesticide intoxication incident: The importance of robust analytical approaches
  8. Induction of apoptosis and cell cycle arrest by chloroform fraction of Juniperus phoenicea and chemical constituents analysis
  9. Recovery of γ-Fe2O3 from copper ore tailings by magnetization roasting and magnetic separation
  10. Effects of different extraction methods on antioxidant properties of blueberry anthocyanins
  11. Modeling the removal of methylene blue dye using a graphene oxide/TiO2/SiO2 nanocomposite under sunlight irradiation by intelligent system
  12. Antimicrobial and antioxidant activities of Cinnamomum cassia essential oil and its application in food preservation
  13. Full spectrum and genetic algorithm-selected spectrum-based chemometric methods for simultaneous determination of azilsartan medoxomil, chlorthalidone, and azilsartan: Development, validation, and application on commercial dosage form
  14. Evaluation of the performance of immunoblot and immunodot techniques used to identify autoantibodies in patients with autoimmune diseases
  15. Computational studies by molecular docking of some antiviral drugs with COVID-19 receptors are an approach to medication for COVID-19
  16. Synthesis of amides and esters containing furan rings under microwave-assisted conditions
  17. Simultaneous removal efficiency of H2S and CO2 by high-gravity rotating packed bed: Experiments and simulation
  18. Design, synthesis, and biological activities of novel thiophene, pyrimidine, pyrazole, pyridine, coumarin and isoxazole: Dydrogesterone derivatives as antitumor agents
  19. Content and composition analysis of polysaccharides from Blaps rynchopetera and its macrophage phagocytic activity
  20. A new series of 2,4-thiazolidinediones endowed with potent aldose reductase inhibitory activity
  21. Assessing encapsulation of curcumin in cocoliposome: In vitro study
  22. Rare norisodinosterol derivatives from Xenia umbellata: Isolation and anti-proliferative activity
  23. Comparative study of antioxidant and anticancer activities and HPTLC quantification of rutin in white radish (Raphanus sativus L.) leaves and root extracts grown in Saudi Arabia
  24. Comparison of adsorption properties of commercial silica and rice husk ash (RHA) silica: A study by NIR spectroscopy
  25. Sodium borohydride (NaBH4) as a high-capacity material for next-generation sodium-ion capacitors
  26. Aroma components of tobacco powder from different producing areas based on gas chromatography ion mobility spectrometry
  27. The effects of salinity on changes in characteristics of soils collected in a saline region of the Mekong Delta, Vietnam
  28. Synthesis, properties, and activity of MoVTeNbO catalysts modified by zirconia-pillared clays in oxidative dehydrogenation of ethane
  29. Synthesis and crystal structure of N,N′-bis(4-chlorophenyl)thiourea N,N-dimethylformamide
  30. Quantitative analysis of volatile compounds of four Chinese traditional liquors by SPME-GC-MS and determination of total phenolic contents and antioxidant activities
  31. A novel separation method of the valuable components for activated clay production wastewater
  32. On ve-degree- and ev-degree-based topological properties of crystallographic structure of cuprite Cu2O
  33. Antihyperglycemic effect and phytochemical investigation of Rubia cordifolia (Indian Madder) leaves extract
  34. Microsphere molecularly imprinted solid-phase extraction for diazepam analysis using itaconic acid as a monomer in propanol
  35. A nitric oxide-releasing prodrug promotes apoptosis in human renal carcinoma cells: Involvement of reactive oxygen species
  36. Machine vision-based driving and feedback scheme for digital microfluidics system
  37. Study on the application of a steam-foam drive profile modification technology for heavy oil reservoir development
  38. Ni–Ru-containing mixed oxide-based composites as precursors for ethanol steam reforming catalysts: Effect of the synthesis methods on the structural and catalytic properties
  39. Preparation of composite soybean straw-based materials by LDHs modifying as a solid sorbent for removal of Pb(ii) from water samples
  40. Synthesis and spectral characterizations of vanadyl(ii) and chromium(iii) mixed ligand complexes containing metformin drug and glycine amino acid
  41. In vitro evaluation of lactic acid bacteria with probiotic activity isolated from local pickled leaf mustard from Wuwei in Anhui as substitutes for chemical synthetic additives
  42. Utilization and simulation of innovative new binuclear Co(ii), Ni(ii), Cu(ii), and Zn(ii) diimine Schiff base complexes in sterilization and coronavirus resistance (Covid-19)
  43. Phosphorylation of Pit-1 by cyclin-dependent kinase 5 at serine 126 is associated with cell proliferation and poor prognosis in prolactinomas
  44. Molecularly imprinted membrane for transport of urea, creatinine, and vitamin B12 as a hemodialysis candidate membrane
  45. Optimization of Murrayafoline A ethanol extraction process from the roots of Glycosmis stenocarpa, and evaluation of its Tumorigenesis inhibition activity on Hep-G2 cells
  46. Highly sensitive determination of α-lipoic acid in pharmaceuticals on a boron-doped diamond electrode
  47. Synthesis, chemo-informatics, and anticancer evaluation of fluorophenyl-isoxazole derivatives
  48. In vitro and in vivo investigation of polypharmacology of propolis extract as anticancer, antibacterial, anti-inflammatory, and chemical properties
  49. Topological indices of bipolar fuzzy incidence graph
  50. Preparation of Fe3O4@SiO2–ZnO catalyst and its catalytic synthesis of rosin glycol ester
  51. Construction of a new luminescent Cd(ii) compound for the detection of Fe3+ and treatment of Hepatitis B
  52. Investigation of bovine serum albumin aggregation upon exposure to silver(i) and copper(ii) metal ions using Zetasizer
  53. Discoloration of methylene blue at neutral pH by heterogeneous photo-Fenton-like reactions using crystalline and amorphous iron oxides
  54. Optimized extraction of polyphenols from leaves of Rosemary (Rosmarinus officinalis L.) grown in Lam Dong province, Vietnam, and evaluation of their antioxidant capacity
  55. Synthesis of novel thiourea-/urea-benzimidazole derivatives as anticancer agents
  56. Potency and selectivity indices of Myristica fragrans Houtt. mace chloroform extract against non-clinical and clinical human pathogens
  57. Simple modifications of nicotinic, isonicotinic, and 2,6-dichloroisonicotinic acids toward new weapons against plant diseases
  58. Synthesis, optical and structural characterisation of ZnS nanoparticles derived from Zn(ii) dithiocarbamate complexes
  59. Presence of short and cyclic peptides in Acacia and Ziziphus honeys may potentiate their medicinal values
  60. The role of vitamin D deficiency and elevated inflammatory biomarkers as risk factors for the progression of diabetic nephropathy in patients with type 2 diabetes mellitus
  61. Quantitative structure–activity relationship study on prolonged anticonvulsant activity of terpene derivatives in pentylenetetrazole test
  62. GADD45B induced the enhancing of cell viability and proliferation in radiotherapy and increased the radioresistance of HONE1 cells
  63. Cannabis sativa L. chemical compositions as potential plasmodium falciparum dihydrofolate reductase-thymidinesynthase enzyme inhibitors: An in silico study for drug development
  64. Dynamics of λ-cyhalothrin disappearance and expression of selected P450 genes in bees depending on the ambient temperature
  65. Identification of synthetic cannabinoid methyl 2-{[1-(cyclohexylmethyl)-1H-indol-3-yl] formamido}-3-methylbutanoate using modern mass spectrometry and nuclear magnetic resonance techniques
  66. Study on the speciation of arsenic in the genuine medicinal material honeysuckle
  67. Two Cu(ii)-based coordination polymers: Crystal structures and treatment activity on periodontitis
  68. Conversion of furfuryl alcohol to ethyl levulinate in the presence of mesoporous aluminosilicate catalyst
  69. Review Articles
  70. Hsien Wu and his major contributions to the chemical era of immunology
  71. Overview of the major classes of new psychoactive substances, psychoactive effects, analytical determination and conformational analysis of selected illegal drugs
  72. An overview of persistent organic pollutants along the coastal environment of Kuwait
  73. Mechanism underlying sevoflurane-induced protection in cerebral ischemia–reperfusion injury
  74. COVID-19 and SARS-CoV-2: Everything we know so far – A comprehensive review
  75. Challenge of diabetes mellitus and researchers’ contributions to its control
  76. Advances in the design and application of transition metal oxide-based supercapacitors
  77. Color and composition of beauty products formulated with lemongrass essential oil: Cosmetics formulation with lemongrass essential oil
  78. The structural chemistry of zinc(ii) and nickel(ii) dithiocarbamate complexes
  79. Bioprospecting for antituberculosis natural products – A review
  80. Recent progress in direct urea fuel cell
  81. Rapid Communications
  82. A comparative morphological study of titanium dioxide surface layer dental implants
  83. Changes in the antioxidative properties of honeys during their fermentation
  84. Erratum
  85. Erratum to “Corrosion study of copper in aqueous sulfuric acid solution in the presence of (2E,5E)-2,5-dibenzylidenecyclopentanone and (2E,5E)-bis[(4-dimethylamino)benzylidene]cyclopentanone: Experimental and theoretical study”
  86. Erratum to “Modified TDAE petroleum plasticiser”
  87. Corrigendum
  88. Corrigendum to “A nitric oxide-releasing prodrug promotes apoptosis in human renal carcinoma cells: Involvement of reactive oxygen species”
  89. Special Issue on 3rd IC3PE 2020
  90. Visible light-responsive photocatalyst of SnO2/rGO prepared using Pometia pinnata leaf extract
  91. Antihyperglycemic activity of Centella asiatica (L.) Urb. leaf ethanol extract SNEDDS in zebrafish (Danio rerio)
  92. Selection of oil extraction process from Chlorella species of microalgae by using multi-criteria decision analysis technique for biodiesel production
  93. Special Issue on the 14th Joint Conference of Chemistry (14JCC)
  94. Synthesis and in vitro cytotoxicity evaluation of isatin-pyrrole derivatives against HepG2 cell line
  95. CO2 gas separation using mixed matrix membranes based on polyethersulfone/MIL-100(Al)
  96. Effect of synthesis and activation methods on the character of CoMo/ultrastable Y-zeolite catalysts
  97. Special Issue on Electrochemical Amplified Sensors
  98. Enhancement of graphene oxide through β-cyclodextrin composite to sensitive analysis of an antidepressant: Sulpiride
  99. Investigation of the spectroelectrochemical behavior of quercetin isolated from Zanthoxylum bungeanum
  100. An electrochemical sensor for high sensitive determination of lysozyme based on the aptamer competition approach
  101. An improved non-enzymatic electrochemical sensor amplified with CuO nanostructures for sensitive determination of uric acid
  102. Special Issue on Applied Biochemistry and Biotechnology 2020
  103. Fast discrimination of avocado oil for different extracted methods using headspace-gas chromatography-ion mobility spectroscopy with PCA based on volatile organic compounds
  104. Effect of alkali bases on the synthesis of ZnO quantum dots
  105. Quality evaluation of Cabernet Sauvignon wines in different vintages by 1H nuclear magnetic resonance-based metabolomics
  106. Special Issue on the Joint Science Congress of Materials and Polymers (ISCMP 2019)
  107. Diatomaceous Earth: Characterization, thermal modification, and application
  108. Electrochemical determination of atenolol and propranolol using a carbon paste sensor modified with natural ilmenite
  109. Special Issue on the Conference of Energy, Fuels, Environment 2020
  110. Assessment of the mercury contamination of landfilled and recovered foundry waste – a case study
  111. Primary energy consumption in selected EU Countries compared to global trends
  112. Modified TDAE petroleum plasticiser
  113. Use of glycerol waste in lactic acid bacteria metabolism for the production of lactic acid: State of the art in Poland
  114. Topical Issue on Applications of Mathematics in Chemistry
  115. Theoretical study of energy, inertia and nullity of phenylene and anthracene
  116. Banhatti, revan and hyper-indices of silicon carbide Si2C3-III[n,m]
  117. Topical Issue on Agriculture
  118. Occurrence of mycotoxins in selected agricultural and commercial products available in eastern Poland
  119. Special Issue on Ethnobotanical, Phytochemical and Biological Investigation of Medicinal Plants
  120. Acute and repeated dose 60-day oral toxicity assessment of chemically characterized Berberis hispanica Boiss. and Reut in Wistar rats
  121. Phytochemical profile, in vitro antioxidant, and anti-protein denaturation activities of Curcuma longa L. rhizome and leaves
  122. Antiplasmodial potential of Eucalyptus obliqua leaf methanolic extract against Plasmodium vivax: An in vitro study
  123. Prunus padus L. bark as a functional promoting component in functional herbal infusions – cyclooxygenase-2 inhibitory, antioxidant, and antimicrobial effects
  124. Molecular and docking studies of tetramethoxy hydroxyflavone compound from Artemisia absinthium against carcinogens found in cigarette smoke
  125. Special Issue on the Joint Science Congress of Materials and Polymers (ISCMP 2020)
  126. Preparation of cypress (Cupressus sempervirens L.) essential oil loaded poly(lactic acid) nanofibers
  127. Influence of mica mineral on flame retardancy and mechanical properties of intumescent flame retardant polypropylene composites
  128. Production and characterization of thermoplastic elastomer foams based on the styrene–ethylene–butylene–styrene (SEBS) rubber and thermoplastic material
  129. Special Issue on Applied Chemistry in Agriculture and Food Science
  130. Impact of essential oils on the development of pathogens of the Fusarium genus and germination parameters of selected crops
  131. Yield, volume, quality, and reduction of biotic stress influenced by titanium application in oilseed rape, winter wheat, and maize cultivations
  132. Influence of potato variety on polyphenol profile composition and glycoalcaloid contents of potato juice
  133. Carryover effect of direct-fed microbial supplementation and early weaning on the growth performance and carcass characteristics of growing Najdi lambs
  134. Special Issue on Applied Biochemistry and Biotechnology (ABB 2021)
  135. The electrochemical redox mechanism and antioxidant activity of polyphenolic compounds based on inlaid multi-walled carbon nanotubes-modified graphite electrode
  136. Study of an adsorption method for trace mercury based on Bacillus subtilis
  137. Special Issue on The 1st Malaysia International Conference on Nanotechnology & Catalysis (MICNC2021)
  138. Mitigating membrane biofouling in biofuel cell system – A review
  139. Mechanical properties of polymeric biomaterials: Modified ePTFE using gamma irradiation
Heruntergeladen am 1.10.2025 von https://www.degruyterbrill.com/document/doi/10.1515/chem-2021-0048/html
Button zum nach oben scrollen