Experimental study on photocatalytic CO2 reduction performance of ZnS/CdS-TiO2 nanotube array thin films

Hanbing Xu; Zhenzhong Fan; Qingwang Liu; Linjing Li

doi:10.1515/chem-2022-0306

Article Open Access

Experimental study on photocatalytic CO₂ reduction performance of ZnS/CdS-TiO₂ nanotube array thin films

Hanbing Xu , Zhenzhong Fan , Qingwang Liu and Linjing Li

Published/Copyright: May 9, 2023

Published by

Become an author with De Gruyter Brill

Submit Manuscript Author Information Explore this Subject

From the journal Open Chemistry Volume 21 Issue 1

Abstract

The effect of CdS/ZnS composite-sensitized TiO₂ nanotube array (TNTA) on the photocatalytic reduction of CO₂ was studied. CdS/ZnS quantum dots sensitized TNTA by successive ionic layer adsorption and reaction (SILAR) cycle method, and CdS/ZnS-TNTA composite semiconductor materials were prepared. The loading amount of CdS/ZnS depends on the number of SILAR cycles. The effects of SILAR cycle times, the CO₂ volume flow, and light intensity on the photocatalytic CO₂ reduction performance were studied. The main product of the photocatalytic reduction of CO₂ was methanol; the performance was 2.73 times higher than that of bare TNTA, the optimal SILAR cycle was 10, the light absorption sideband was red shifted to 524 nm, and the optimal CO₂ volume flow rate was 20.5 mL/min. The final yield was as high as 255.49 nmol/(cm²-cat h). CdS/ZnS quantum dot sensitization mainly broadened the wavelength range of the catalyst’s response to visible light, inhibited the recombination of electron–hole pairs to a certain extent, and greatly improved the photocatalytic performance under visible light.

Keywords: photocatalysis; CO2 ; TiO2 nanotube array film; CdS/ZnS sensitization

1 Introduction

In 1967, Fujishima Akira discovered the photocatalytic phenomenon: with the irradiation of ultraviolet light, the TiO₂ single-crystal electrode decomposed water into oxygen and hydrogen. This phenomenon was called the “Hondo–Fujishima effect” [1]. With the increasingly serious problems of energy shortage and environmental pollution, photocatalytic technology has attracted more and more researchers’ attention. Using photocatalytic technology, one can convert light energy into chemical energy under the conditions of minimal environmental impact. With the progress of scientific research, photocatalysis technology, as an interdisciplinary subject, is involved in various fields such as energy, environment, materials, chemistry, and physics. The research of photocatalysis was mainly used in hydrolysis to produce hydrogen, degrade pollutants [2–5], for air purification [6,7], stability [8], reduction of greenhouse gases [9], fuel cells [10], and so on. Photocatalytic reactions combine photochemistry and catalytic chemistry, and the most widely studied photocatalysts are semiconductor catalysts. The semiconductor photocatalyst is active under light irradiation; the electrons jump from the original valence band position to the conduction band, and the valence band loses electrons to form photogenerated holes, thus generating electron–hole pairs with both oxidizing and reducing ability.

Due to its wide band gap, TiO₂ has a weak absorption capacity in the visible light band and can only respond to ultraviolet light. However, ultraviolet light accounts for only 5% in nature. Therefore, solar energy can be used more effectively if the photocatalyst is broadened to visible light. To further broaden the visible light response, semiconductor composite TiO₂ nanomaterials are one of the most effective methods. The common semiconductor materials are CdS, ZnS, CdSe, PbS, etc. CdS has a narrow band gap, and its recombination with TiO₂ can not only enhance the response to visible light but also inhibit the recombination of electron–hole pairs. ZnS has a higher negative conduction band bottom potential and a strong reducing ability, which is beneficial to the reduction of CO₂ [11]. Both are very potential photocatalytic CO₂ reduction materials. The photocatalyst combining CdS and ZnS with TiO₂ not only shifts the response wavelength to the visible light range but also inhibits the recombination of electron–hole pairs and even enhances the ability to reduce CO₂.

Beigi et al. [12] prepared CdS–TiO₂ nanoparticle composites with different mass ratios by the hydrothermal method, and the photocatalytic conversion of CO₂ was experimentally studied in a batch gas-phase reactor. The results showed that the catalyst was active under UV light and visible light. It can also inhibit the recombination of electron–hole pairs and even enhance the ability to reduce CO₂. Chen et al. [13] reported a variety of methods to prepare the ZnS photocatalyst and the photocatalytic reduction of CO₂ to produce methyl formate. Tang et al. [14] studied the ZnS/CdS monodisperse nanosphere composite catalyst by changing the ratio of Zn/Cd to control the band gap of the composite catalyst for the photocatalytic reduction of CO₂. The study showed that the CH₃OH yield was the highest when the ratio of Zn/Cd was 2:8.

Herein, the TiO₂ nanotube array (TNTA) film was sensitized by CdS/ZnS quantum dots, and the composite CdS/ZnS–TiO₂ nanotube array (CdS/ZnS-TNTA) photocatalyst was prepared and characterized by X-ray diffraction (XRD), SEM, energy-dispersive X-ray spectroscopy (EDS), TEM, and X-ray photoelectron spectroscopy (XPS). The photocatalytic reduction of gas-phase CO₂ was evaluated in a microreactor under the simulation of visible light. The effects of different quantum dot sensitization cycles, the CO₂ volume flow, and light intensity on the reaction performance were also analyzed.

2 Experimental section

2.1 Materials

Ethanol and acetone were purchased from China Chuandong Chemical Co., Ltd. Distilled water (≥18.2 MΩ) was made in our laboratory using a deionized water machine. Ammonium fluoride (NH₄F) was purchased from Chengdu Kelon Company, China. Ethylene glycol was purchased from Shanghai Titan Technology, Company, China. Cadmium nitrate tetrahydrate (Cd(NO₃)₂·4H₂O), zinc nitrate hexahydrate (Zn(NO₃)₂·6H₂O), and sodium sulfide nonahydrate (Na₂S·9H₂O) were purchased from Sigma-Aldrich.

2.2 Preparation of CdS/ZnS-TNTA

2.2.1 Preparation of one-dimensional TNTA films

① The pretreatment of the Ti sheet

The pure titanium sheet (purity: 99.96%, size: 20 mm × 25 mm × 0.3 mm) was ultrasonically cleaned with a 1:1 mixed solution of ethanol/acetone for 15 min to remove impurities such as surface organics. Then, the pure titanium sheet was ultrasonically cleaned with deionized water for 15 min to remove the residual ethanol and acetone on the surface. Then, the pure titanium sheet was taken out and placed in a drying oven at 60°C for drying.
② The preparation of the electrolyte

NH₄F (0.25 mol/L) and deionized water (2.5 v%) were added into ethylene glycol (≥99.0%) and stirred with a magnetic stirrer for 10 h to fully dissolve NH₄F.
③ Anodic oxidation

The Ti sheet was immersed in the newly prepared electrolyte as the anode, and the graphite plate (size: 45 mm × 40 mm × 50 mm) was used as the cathode. The distance between the cathode and anode was kept at 3 cm, and a 60 V regulated DC power supply was applied at 25°C for 4 h.
④ After treatment of the Ti sheet

After the anodization, the applied voltage was removed, the Ti sheet was taken out, washed with deionized water, and dried in the natural environment. Then, the anodized Ti sheets were placed in an atmosphere tube furnace and calcined at a rate of 2°C/min to 500°C for 3 h in the air, and then naturally cooled to room temperature.

2.2.2 Quantum dot sensitization of CdS/ZnS

① About 5.78 g of Cd(NO₃)₂·4H₂O and 1.86 g of Zn(NO₃)₂·6H₂O were added into 250 mL of deionized water and fully dissolved to obtain 0.075 mol/L Cd²⁺ solution.

② About 6 g of Na₂S·9H₂O was added into 250 mL of deionized water to obtain 0.1 mol/L Na₂S solution.

③ TNTA was immersed in the metal salt solution for 5 min and then taken out and washed with deionized water.

④ The cleaned TNTA was immersed in the Na₂S solution for 5 min, taken out, and again washed with deionized water for 2 min so that CdS and ZnS precipitates were formed on the surface of TiO₂; a successive ionic layer adsorption and reaction (SILAR) cycle was completed.

⑤ Steps ③ and ④ were repeated for different cycle times (4, 7, 10, 13, and 16 times; the products were named S04 CdS/ZnS-TNTA, S07 CdS/ZnS-TNTA, S10 CdS/ZnS-TNTA, S13 CdS/ZnS-TNTA, S16 CdS/ZnS-TNTA, respectively). It can be observed that with the increase of the number of cycles, the color of the nanotube gradually changed from light gray-blue to yellow, indicating that the loading of CdS and ZnS was gradually increasing.

⑥ TNTA was taken out and put into the oven at 100℃ for 20 min for drying, and the sensitization was completed.

2.2.3 Photocatalytic reduction of CO₂ experiment

The photocatalytic experimental system is shown in Figure 1. It was mainly divided into three steps: generating a mixed gas of CO₂ and H₂O, photocatalytic reduction of the CO₂ reaction, and product collection and analysis.

Figure 1

Schematic diagram of the photocatalytic reduction system.

2.3 Characterization

2.3.1 XRD analysis

XRD spectra of the samples were recorded by using a Bruker D8 ADVANCE (Bruker, Germany). The Cu target Kα (λ = 1.540593) line was used as the incident wave; the 2θ angle scanning range was 10–90°, the scanning rate was 6°/min, and the scanning step was 0.02.

2.3.2 XPS analysis

The XPS instrument used was Thermo escalab 250Xi (American Thermoelectric Company). The light source adopted an aluminum target; the power was 150 W, the beam spot was 500 μm, and the full spectrum scanning range was 0–1,200 eV.

2.3.3 Ultraviolet-Vis absorption spectroscopy (UV-vis) analysis

UV-vis absorption spectroscopy was performed on a UV-3600 UV-Vis spectrophotometer (Shimadzu Corporation, Japan), with a high-performance double monochromator. The standard sample was BaSO₄, and the scanning spectral range used was 200–800 nm.

2.3.4 SEM analysis

The SEM model SU8020 was used for the analysis (Hitachi, Japan), with a cold cathode field emission electron source; the cross section and the surface of the sample were observed with different resolutions.

2.3.5 TEM analysis

The TEM Tecnai G2 F20 model was used for the analysis (FEI Company, USA). The point resolution was 0.24 nm, the energy resolution of the X-ray energy spectrometer was 130 eV, and the accelerating voltage was 200 kV.

3 Results and discussion

3.1 XRD analysis of the bare TNTA and CdS/ZnS-TNTA (10 cycles)

The XRD patterns of bare TNTA and sensitized CdS/ZnS-TNTA (ten cycles) are shown in Figure 2. The characteristic peak positions of the bare TNTA and sensitized CdS/ZnS-TNTA (ten cycles) were basically the same. The diffraction peaks observed at 2θ values of 24.9, 37.8, 48.2, 53.4, 54.8, 62.7, 68.9, and 75.1° can be assigned to the (101), (004), (200), (105), (211), (204), (220), (215) of TiO₂ anatase phase, respectively (JCPDS No. 34-0394). Due to the low loading, the weak diffraction peaks of CdS and ZnS were observed after zooming the spectrum. The diffraction peaks observed at 2θ values of 26.55, 44.05, and 52.9° can be assigned to the (111), (220), (311) of cubic CdS, respectively (JCPDS No.75-1546). The diffraction peaks observed at 2θ values of 28.91 and 48.27° can be assigned to (111) and (220) of cubic ZnS (JCPDS Card No.75-1546) [15]. It showed that quantum dots were successfully sensitized CdS and ZnS on the surface of TiO₂ nanotubes.

Figure 2

XRD patterns of bare TNTA and CdS/ZnS-TNTA (ten cycles).

3.2 XPS spectra analysis of bare TNTA and CdS/ZnS-TNTA (ten cycles)

To further study the chemical composition of TNTA sensitized by CDS/ZnS quantum dots, bare TNTA and sensitized CdS/ZnS-TNTA (ten cycles) were analyzed by XPS. As shown in Figure 3, the characteristic peak positions of bare TNTA and sensitized CdS/ZnS-TNTA (ten cycles) were basically the same. The binding energies at 458 eV (Ti2p), 284.6 eV (C1s), and 529.3 eV (O1s) had obvious characteristic peaks. In addition, the binding energies at 162 eV(S2p), 405 eV(Cd3d), and 1,022 eV(Zn2p) had weak characteristic peaks. It can be seen that Cd, Zn, and S elements did enter the S10 CdS/ZnS-TNTA samples.

Figure 3

XPS survey spectra of bare TNTA and CdS/ZnS-TNTA (ten cycles).

In addition, to determine the valence states of the elements, S2p, Cd3d, Zn2p, and Ti2p were analyzed by high-resolution XPS. As shown in Figure 4(a), the high-resolution energy spectrum of Cd, the binding energies of 405.5 and 412.2 eV correspond to the peaks of Cd3d_5/2 and Cd3d_3/2, which can match the element Cd in the sample in the form of Cd²⁺ [16]. As shown in Figure 4(b), the difference in the binding energy between Ti2p_3/2 and Ti2p_1/2 was 5.7 eV, which was consistent with the characteristic peaks of Ti⁴⁺ reported in some studies [17,18,19], indicating that Ti existed mainly in the compound form of TiO₂. The high-resolution energy spectrum of element S is shown in Figure 4(c). It was observed that the binding energies of 161.2 and 162.4 eV of the two characteristic peaks strongly corresponded to S2p_3/2 and S2p_1/2, indicating that element S mainly existed on the surface of the sample in the form of an S²⁻ chemical state, which further proved that ZnS and CdS were formed on the surface of the sample by quantum dot sensitization. In addition, a characteristic peak with lower intensity appeared at 168.8 eV and corresponded to the form of S⁶⁺. Due to the sensitization of ZnS and CdS, CdS was prone to photocorrosion in air, indicating that a small amount of CdS nanoparticles were oxidized on the surface [20,21,22].

Figure 4

High-resolution XPS spectra of Cd 3d (a), Ti 2p (b), S2p (c), and Zn 2p (d) regions recorded on the CdS/ZnS-TNTA (ten cycles).

3.3 UV-vis absorption spectra of bare TNTA and CdS/ZnS-TNTA

The UV-Vis diffuse reflectance spectra of TNTA sensitized by CdS/ZnS quantum dots with different SILAR cycles are shown in Figure 5. When the number of SILAR cycles increased, the absorption capacity of the catalyst in visible light was gradually enhanced. Then, the absorption capacity of the catalyst in the UV light was gradually weakened, and the wavelength sideband of light absorption was constantly red-shifted.

Figure 5

UV-vis absorption spectra of bare TNTA and CdS/ZnS-TNTA (different cycles).

Due to the increase of the number of cycles after 13–16 cycles, the deposition of CdS/ZnS on the surface of TNTA increased, and the visible light was more easily absorbed by CdS. With the increase of the CdS content, the absorbed visible light gradually increased, which improved the absorption capacity of the catalyst in the visible light band. CdS/ZnS-sensitized TNTA had great potential for photocatalytic reduction of CO₂ by solar energy.

3.4 Cross-sectional SEM analysis of CdS/ZnS-TNTA (ten cycles)

To analyze the morphology of TNTA after sensitization of CdS/ZnS quantum dots, the cross-sectional SEM images of CdS/ZnS-TNTA after 10 SILAR cycles were obtained, as shown in Figure 6. It was observed that the outer wall of the nanotubes became rough, and a layer of small-sized nanoparticles was uniformly attached to the outer wall; the particle size was about 11 nm. This indicated that the SILAR cycle method successfully introduced CdS/ZnS into the gap between the nanotubes, and it was speculated that it would also be loaded on the inner wall of each tube hole. After a certain amount of nanoparticles was evenly loaded on the smooth wall of TNTA, the specific surface area of the catalyst can be further improved. The photocatalytic reaction area was increased, thereby improving the photocatalytic performance.

Figure 6

Cross-sectional SEM images of CdS/ZnS-TNTA (ten cycles).

The surface top-view SEM morphologies of TNTA and bare TNTA after sensitization of CdS/ZnS quantum dots for 10 SILAR cycles are shown in Figure 7. The bare TNTA was smooth and the interface was clear without impurities, while the surface of sensitized TNTA was rough and the cross section was blurred. Most of the CdS and ZnS nanoparticles were evenly attached on TNTA, and a small number of particles agglomerated. The average particle size was about 18.31 nm, indicating that the CdS/ZnS-TNTA composite semiconductor material was successfully prepared by the quantum dot sensitization method. The granular CdS/ZnS did not block the mouth of the nanotubes, and the rough particles increased the specific surface area. SEM with EDS was used to analyze the element surface distribution of the front section and the top surface of the sample. As shown in Figure 8, the point densities of Zn, Cd, and S elements on the upper nanotubes were higher, indicating that CdS/ZnS was mainly loaded on the upper part of the wall of TNTA. As shown in Figure 9, the approximate ratios of the five elements, Ti, O, Cd, Zn, and S, are clearly shown. Cd, Zn, and S were evenly distributed on the surface of TNTA, indicating that ZnS and CdS successfully deposited on the surface of TNTA. The ratio of O/Ti atoms was close to 2:1, and the number of Cd atoms was 16–20 times that of Zn atoms.

Figure 7

SEM images of (a and b) external bare TNTA and (c and d) CdS/ZnS-TNTA (ten cycles).

Figure 8

SEM–EDS elemental cross-sectional mapping of CdS/ZnS-TNTA (ten cycles).

Figure 9

SEM–EDS elemental top view mapping of CdS/ZnS-TNTA (ten cycles).

3.5 TEM analysis of bare TNTA and CdS/ZnS-TNTA

The TEM image of TNTA sensitized by CdS/ZnS quantum dots after ten SILAR cycles is shown in Figure 10. It can be seen that a thin layer of CdS/ZnS nanoparticles of different sizes was wrapped on the inner and outer walls of the nanotubes. As shown in Figure 10(b), the crystal lattices of anatase TiO₂, CdS, and ZnS of the sample were clearly visible, and {100} of CdS, {111} of ZnS, and {111} of anatase TiO₂ also appeared. The {101} and {004} planes and the measured lattice spacings were 0.359, 0.310, 0.352, and 0.237 nm, respectively [23,24]. It can be seen from Figure 10(d) that the {100} plane of CdS was attached to the {004} plane of TiO₂ at a certain angle, and a small amount of the {004} plane of TiO₂ was unexpectedly observed through the lattice distortion region [25].

Figure 10

(a) TEM and HR-TEM (b)–(d) images of CdS/ZnS-TNTA (ten cycles).

3.6 Experimental results and analysis of CdS/ZnS-TNTA photocatalytic reduction of CO₂ under simulated visible light

3.6.1 Effect of quantum dot sensitization with different cycle times on the performance

CdS/ZnS quantum dot-sensitized TNTA samples for 4, 7, 10, 13, and 16 SILAR cycles were prepared to study the effect of different CdS/ZnS loadings on the photocatalytic performance of TNTA surfaces. This was used for the performance test of photocatalytic reduction of gas-phase CO₂ and compared with bare TNTA. The results are shown in Figure 11. The volume flow of CO₂ was 20 mL/min, and the visible light intensity was 50 mW/cm². The results showed that compared with the bare TNTA, the yields of all the sensitized samples were high, with the highest yield being 193.63 nmol/(cm² h) for ten SILAR cycles. With the increase of the number of cycles, the product yield of photocatalytic reduction of CO₂ first increased and then decreased. The increase in the yield was can be explained as follows: (1) The forbidden band width of ZnS was wider than that of TiO₂, and both had different valence and conduction band positions, which can make electrons and holes in different phases of the compound semiconductor and inhibit the recombination of electron–hole pairs [26]. (2) CdS had a narrower forbidden band width, which can not only effectively expand the wavelength range of photoresponse but also speed up the separation of electron–hole pairs. ZnS and CdS had stronger reducibility to reduce CO₂. Therefore, the sensitization of a certain amount of CdS/ZnS can promote the photocatalytic reduction of CO₂ under visible light. When the number of cycles increased to 10, the yield tended to decrease. This may be because, with the increase of the number of cycles, CdS/ZnS tend to form agglomerates on the surface, resulting in an increase in the size of the nanoparticles [27]. The nanotube pores were blocked by a large area of TiO₂ [25], which greatly reduced the reaction area and the reaction rate. The composite semiconductor catalyst obtained by sensitizing CdS/ZnS quantum dots with suitable SILAR cycle times can greatly improve the methanol yield for the catalytic reduction of CO₂ under visible light.

Figure 11

Methanol yield of CdS/ZnS-TNTA (different cycles).

3.6.2 Effect of different CO₂ volume flow rates on the performance

The visible light intensity was 50 mW/cm², and other experimental procedures and reaction conditions remained unchanged. The methanol yield of photocatalytic reduction of CO₂ by CdS/ZnS quantum dot-sensitized TNTA for ten SILAR cycles under different CO₂ volume flow rates is shown in Figure 12. The experimental results showed that with the increase of the CO₂ volume flow rate, methanol production first increased and then decreased. The flow rate of CO₂ directly affected the flow rate of the reactants and thus affected the amount of the reactants passing through the catalyst surface per unit of time. When the flow rate was too small, the output per unit time was also very small due to less reactive substances. The increase of the flow rate can increase the diffusion of the reactants to the surface of the catalytic layer sufficiently and rapidly, and a sufficient amount of the reactants can also improve the yield and also accelerate the desorption of the reaction products to prevent them from being oxidized by holes. If the flow rate was too high, the reaction material would be taken out of the reaction chamber before being adsorbed by the catalytic layer, so that the reaction cannot be fully carried out. At the same time, the hydroxyl groups that could improve the catalytic activity were quickly taken away and could not be replenished in time, which also reduced the catalytic activity. The optimal CO₂ volume flow rate obtained in the experiment was 20.5 mL/min, and the methanol yield was 193.63 nmol/(cm² h).

Figure 12

Methanol yield of CdS/ZnS-TNTA (10 cycles) with different CO₂ fluxes.

3.6.3 Effect of different visible light intensities on the performance

As shown in Figure 13, the effects of different light intensities on the photocatalytic reduction of CO₂ by CdS/ZnS quantum dots sensitized by TNTA were investigated experimentally. The optimal number of SILAR cycles was 10, and the CO₂ volume flow rate was 20.5 mL/min. The experimental results showed that the methanol production increased continuously with the increase of light intensity, reaching 255.49 nmol/(cm² h) when the light intensity was 110 mW/cm², CdS can absorb visible light due to its narrow band gap. This showed that CdS/ZnS quantum dot-sensitized TNTA had a strong utilization ability of visible light. Therefore, the increase of light intensity stimulated more electrons to transition from the valence band to the conduction band and produced more electron–hole pairs, which accelerated the reaction and greatly improved the reaction rate of photocatalysis.

Figure 13

Methanol yield of CdS/ZnS-TNTA (ten cycles) at different light intensities.

4 Conclusion

The bare TNTA was obtained by anodizing and calcining at 500°C. CdS/ZnS quantum dots sensitized by the SILAR cycle method were used to prepare the CdS/ZnS TNTA composite catalyst material. Experiments were carried out to study the performance of the two samples in the photocatalytic reduction of gas-phase CO₂ under visible light in the microreactor. Under visible light, the optimal yield of the sample obtained by sensitizing CdS/ZnS quantum dots for ten SILAR cycles was 193.63 nmol/(cm² h) and the optimal CO₂ volume flow rate was 20.5 mL/min. The methanol yield increased with the light intensity. Compared with bare TNTA, the performance of CdS/ZnS quantum dots after sensitization was greatly improved. The sensitization of CdS/ZnS broadened the absorption range of visible light and inhibited the recombination of electron–hole pairs. Meanwhile, the CdS/ZnS nanoparticles on the surface of TNTA increased the specific surface area. The number of SILAR cycles, flow rate, and light intensity all had significant effects on the methanol yield, and appropriate reaction conditions can optimize the catalytic efficiency.

Funding information: This project was supported by the Heilongjiang Province Natural Science Foundation (No. LH2020E014).
Author contributions: Hanbing Xu: performed the experiment and data processing. Zhenzhong Fan: initiated the project. Qingwang Liu and Linjing Li: edited the manuscript.
Conflict of interest: The authors state that there was no conflict of interest.
Ethical approval: The conducted research is not related to either human or animal use.
Data availability statement: The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

References

[1] Inoue T, Fujishima A, Konishi S, Honda K. Photoelectrocatalytic reduction of carbon dioxide in aqueous suspensions of semiconductor powders. Nature. 1979;277(5698):637–8.10.1038/277637a0Search in Google Scholar

[2] Nakashima T, Ohko Y, Kubota Y, Fujishima A. Photocatalytic decomposition of estrogens in aquatic environment by reciprocating immersion of TiO2-modified polytetrafluoroethylene mesh sheets. J Photochem Photobiol A Chem. 2003;160(1):115–20.10.1016/S1010-6030(03)00229-6Search in Google Scholar

[3] Zoubi WA, Ko YG. Enhanced chemical stability and boosted photoactivity by transition metal doped-crosslinked polymer-inorganic materials. J Mol Liq. 2020;303:112700.10.1016/j.molliq.2020.112700Search in Google Scholar

[4] Al Zoubi W, Kamil MP, Fatimah S, Nashrah N, Ko YG. Recent advances in hybrid organic-inorganic materials with spatial architecture for state-of-the-art applications. Prog Mater Sci. 2020;112:100663.10.1016/j.pmatsci.2020.100663Search in Google Scholar

[5] Al Zoubi W, Kim MJ, Kim YG, Ko YG. Fabrication of graphene oxide/8-hydroxyquinolin/inorganic coating on the magnesium surface for extraordinary corrosion protection. Prog Org Coat An Int Rev J. 2019;137:137.10.1016/j.porgcoat.2019.105314Search in Google Scholar

[6] Fujishima A, Zhang X, Tryk DA. TiO2 photocatalysis and related surface phenomena. Surf Sci Rep. 2008;63(12):515–82.10.1016/j.surfrep.2008.10.001Search in Google Scholar

[7] Zoubi WA, Nashrah N, Putri R. Strong dual-metal-support interactions induced by low-temperature plasma phenomenon. Mater Today Nano. 2022;18:18.10.1016/j.mtnano.2022.100213Search in Google Scholar

[8] Allaf AW, Assfour B, Zoubi WA, Ko YG. Concurrent Oxidation-Reduction Reactions in a Single System Using a Low-Plasma Phenomenon: Excellent Catalytic Performance and Stability in the Hydrogenation Reaction. ACS Appl Mater Interfaces. 2022;14(5):6740–53.10.1021/acsami.1c22192Search in Google Scholar PubMed

[9] Varghese OK, Paulose M, Latempa TJ, Grimes CA. High-rate solar photocatalytic conversion of CO2 and water vapor to hydrocarbon fuels. Nano Lett. 2009;9(2):731–7.10.1021/nl803258pSearch in Google Scholar PubMed

[10] Jiao X, Chen R, Zhu X, Liao Q, Ye D, Zhang B, et al. A microfluidic all-vanadium photoelectrochemical cell for solar energy storage. Electrochim Acta. 2017;258:842–9. S0013468617324969.10.1016/j.electacta.2017.11.134Search in Google Scholar

[11] Fang X, Zhai T, Gautam UK, Li L, Wu L, Bando Y, et al. ZnS nanostructures: From synthesis to applications. Prog Mater Sci. 2011;56(2):175–287.10.1016/j.pmatsci.2010.10.001Search in Google Scholar

[12] Beigi AA, Fatemi S, Salehi Z. Synthesis of nanocomposite CdS/TiO2 and investigation of its photocatalytic activity for CO2 reduction to CO and CH4 under visible light irradiation. J CO2 Util. 2014;7(7):23–9.10.1016/j.jcou.2014.06.003Search in Google Scholar

[13] Chen J, Xin F, Qin S, Yin X. Photocatalytically reducing CO2 to methyl formate in methanol over ZnS and Ni-doped ZnS photocatalysts. Chem Eng J. 2013;230(16):506–12.10.1016/j.cej.2013.06.119Search in Google Scholar

[14] Tang L, Kuai L, Li Y, Li H, Zhou Y, Zou Z. ZnxCd1-xS tunable band structure-directing photocatalytic activity and selectivity of visible-light reduction of CO2 into liquid solar fuels. Nanotechnology. 2018;29(6):064003.10.1088/1361-6528/aaa272Search in Google Scholar PubMed

[15] Boxi SS, Paria S. Effect of silver doping on TiO2, CdS, and ZnS nanoparticles for the photocatalytic degradation of metronidazole under visible light. RSC Adv. 2014;4(71):37752–60.10.1039/C4RA06192FSearch in Google Scholar

[16] Li GS, Zhang DQ, Yu JC. A new visible-light photocatalyst: CdS quantum dots embedded mesoporous TiO2. Environ Sci Technol. 2009;43(18):7079–85.10.1021/es9011993Search in Google Scholar PubMed

[17] Ghazzal MN, Chaoui N, Genet M, Gaigneaux EM, Robert D. Effect of compressive stress inducing a band gap narrowing on the photoinduced activities of sol–gel TiO2 films. Thin Solid Films. 2011;520(3):1147–54.10.1016/j.tsf.2011.08.097Search in Google Scholar

[18] Yang G, Jiang Z, Shi H, Xiao T, Yan Z. Preparation of highly visible-light active N-doped TiO2 photocatalyst. J Mater Chem. 2010;20(25):5301–9.10.1039/c0jm00376jSearch in Google Scholar

[19] Chanda A, Rout K, Vasundhara M, Joshi SR, Singh J. Structural and magnetic study of undoped and cobalt doped TiO2 nanoparticles. RSC Adv. 2018;8(20):10939–47.10.1039/C8RA00626ASearch in Google Scholar

[20] Ahmed R, Will G, Bell J, Wang H. Size-dependent photodegradation of CdS particles deposited onto TiO2 mesoporous films by SILAR method. J Nanopart Res. 2012;14(9):1140.10.1007/s11051-012-1140-xSearch in Google Scholar

[21] Chaguetmi S, Mammeri F, Nowak S, Decorse P, Lecoq H, Gaceur M, et al. Photocatalytic activity of TiO2 nanofibers sensitized with ZnS quantum dots. RSC Adv. 2013;3(8):2572–80.10.1039/c2ra21684aSearch in Google Scholar

[22] Jang J, Kim H, Joshi U, JANG J, LEE J. Fabrication of CdS nanowires decorated with TiO2 nanoparticles for photocatalytic hydrogen production under visible light irradiation. Int J Hydrog Energy. 2008;33(21):5975–80.10.1016/j.ijhydene.2008.07.105Search in Google Scholar

[23] Štengl V, Bakardjieva S, Murafa N, et al. Visible-light photocatalytic activity of TiO2/ZnS nanocomposites prepared by homogeneous hydrolysis. Microporous Mesoporous Mater. 2008;110(2):370–8.10.1016/j.micromeso.2007.06.052Search in Google Scholar

[24] Zhao G, Sun M, Liu X, Xuan J, Kong W, Zhang R, et al. Fabrication of CdS quantum dots sensitized ZnO nanorods/TiO2 nanosheets hierarchical heterostructure films for enhanced photoelectrochemical performance. Electrochim Acta. 2019;304:334–41.10.1016/j.electacta.2019.03.022Search in Google Scholar

[25] Cheng S, Fu W, Yang H, Zhang L, Ma J, Zhao H, et al. Photoelectrochemical performance of multiple semiconductors (CdS/CdSe/ZnS) cosensitized TiO2 photoelectrodes. J Phys Chem C. 2012;116(3):2615–21.10.1021/jp209258rSearch in Google Scholar

[26] Antoniadou M, Daskalaki VM, Balis N, Kondarides DI, Kordulis C, Lianos P. Photocatalysis and photoelectrocatalysis using (CdS- ZnS)/TiO2 combined photocatalysts. Appl Catal B Environ. 2011;107(1):188–96.10.1016/j.apcatb.2011.07.013Search in Google Scholar

[27] Ghazzal MN, Wojcieszak R, Raj G, Gaigneaux EM. Study of mesoporous CdS-quantum-dot-sensitized TiO2 films by using X-ray photoelectron spectroscopy and AFM. Beilstein J Nanotechnol, 2014;5(1):68–76.10.3762/bjnano.5.6Search in Google Scholar PubMed PubMed Central

Received: 2022-12-22

Revised: 2023-02-13

Accepted: 2023-02-20

Published Online: 2023-05-09

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

Articles in the same Issue

https://doi.org/10.1515/chem-2022-0306

Keywords for this article

photocatalysis; CO2; TiO2 nanotube array film; CdS/ZnS sensitization

Creative Commons

BY 4.0

Experimental study on photocatalytic CO2 reduction performance of ZnS/CdS-TiO2 nanotube array thin films

Article

Abstract

1 Introduction

2 Experimental section

2.1 Materials

2.2 Preparation of CdS/ZnS-TNTA

2.2.1 Preparation of one-dimensional TNTA films

2.2.2 Quantum dot sensitization of CdS/ZnS

2.2.3 Photocatalytic reduction of CO2 experiment

2.3 Characterization

2.3.1 XRD analysis

2.3.2 XPS analysis

2.3.3 Ultraviolet-Vis absorption spectroscopy (UV-vis) analysis

2.3.4 SEM analysis

2.3.5 TEM analysis

3 Results and discussion

3.1 XRD analysis of the bare TNTA and CdS/ZnS-TNTA (10 cycles)

3.2 XPS spectra analysis of bare TNTA and CdS/ZnS-TNTA (ten cycles)

3.3 UV-vis absorption spectra of bare TNTA and CdS/ZnS-TNTA

3.4 Cross-sectional SEM analysis of CdS/ZnS-TNTA (ten cycles)

3.5 TEM analysis of bare TNTA and CdS/ZnS-TNTA

3.6 Experimental results and analysis of CdS/ZnS-TNTA photocatalytic reduction of CO2 under simulated visible light

3.6.1 Effect of quantum dot sensitization with different cycle times on the performance

3.6.2 Effect of different CO2 volume flow rates on the performance

3.6.3 Effect of different visible light intensities on the performance

4 Conclusion

References

Articles in the same Issue

Articles in the same Issue

Articles in the same Issue

Experimental study on photocatalytic CO₂ reduction performance of ZnS/CdS-TiO₂ nanotube array thin films

2.2.3 Photocatalytic reduction of CO₂ experiment

3.6 Experimental results and analysis of CdS/ZnS-TNTA photocatalytic reduction of CO₂ under simulated visible light

3.6.2 Effect of different CO₂ volume flow rates on the performance