Band 239, Heft 11-12

Binary metal oxide nanoparticles have huge attention nowadays because of their capability for use in energy saving systems. Typically, these compounds have an A x B 3-x O 4 structure, here A and B stands for two dissimilar metals such as Co, Ni, Mn, Fe, and Mo etc., This combination of metal cations (NiCo 2 O 4 , CoMn 2 O 4 , MnCo 2 O 4 , CoFe 2 O 4 , NiFe 2 O 4 , CoNi 2 O 4 ,etc.) provides a wide range of redox reactions and intensify electronic conductivity, which upgrades the electrochemical performance. Binary transition metal oxides provide combined effect of the monometallic oxides, which can enhance conductivity, more active sites, stability and storage capacity. Among binary metal oxides, Cobalt Manganese Oxide (CoMn 2 O 4 ) has outstanding capacitive performance as a result of greater tendency of cobalt to gain electrons and strong electron transport property of manganese. Due to these factors, researchers focus on cobalt manganese oxide-based supercapacitor electrodes. Hence a detailed and exhaustive review of works on CoMn 2 O 4 and its composites as potential candidates for supercapacitor electrode materials is carried out in this article.

Nitrogen-doped hydrogenated amorphous carbon (a-C:H:N) films were synthesized via plasma-activated chemical vapor deposition (PACVD) using a capacitively coupled RF plasma (RF-CCP) source to address the critical challenge of carbon steel corrosion in acidic environments. This study is motivated by the urgent need to replace toxic corrosion inhibitors and improve upon conventional nitriding methods that typically offer <80 % protection in hydrochloric acid. We systematically investigated the effects of plasma power (400–700 W), treatment time (5–20 min), and N 2 /C 2 H 2 gas ratios (0–100 % N 2 ) on film properties and corrosion resistance in 1.0 M HCl. Electrochemical measurements revealed exceptional corrosion inhibition efficiencies (IE %) of 99.3 % for C 2 H 2 -derived films and 99.1 % for N 2 /C 2 H 2 (75/25 %) mixtures – the highest reported values for plasma-treated steel in acidic media. Tafel analysis showed these films preferentially inhibit anodic reactions, reducing corrosion current density from 400 μA/cm 2 (untreated steel) to just 2.7 μA/cm 2 . Surface characterization demonstrated that optimal films combine a hydrophobic carbon matrix (30.23 at.% C by EDX) with nitrogen functionalities (0.68 at.% N), forming a nanostructured barrier that resists acid penetration (SEM). The 700 W, 20 min N 2 treatment achieved 97.7 % IE %, while shorter 10 min treatments maintained 97.6 % efficiency, suggesting energy-saving potential. These results establish that a-C:H:N films deposited at room temperature can provide near-complete corrosion protection through two mechanisms: (1) C–H network formation at high power and (2) synergistic N-doping that enhances passivation. The study provides a scalable, environmentally friendly alternative to conventional coatings for industrial applications involving acid exposure, with quantified performance benchmarks that surpass existing plasma-based methods.

Kurzfassung Es wird ein Bedarf an physikalisch-chemischen Daten zum Treibhauseffekt der Klimaerwärmung festgestellt, da die auf Beobachtung basierende CO 2 -T-Korrelation durch physikalisch-chemische Ergebnisse bisher nicht bestätigt worden ist. Ergebnisse zu den molaren Wärmekapazitäten der atmosphärischen Gase werden diskutiert. Der Beitrag des CO 2 zur Wärmespeicherung in der Atmosphäre erweist sich als vernachlässigbar. Die Rolle der sogenannten Treibhausgase als Transmitter und Sender zwischen der kinetischen Energie der Moleküle und der Photonenenergie im Strahlungsgleichgewicht (speziell im IR-(Infrarot)-Bereich) wird diskutiert. Bilanzen des CO 2 -Austauschs zwischen der Atmosphäre, der Pflanzenwelt und den Ozeanen im Vergleich zu den anthropogenen Emissionen werden kritisch bewertet. Der anthropogene Energiefluss ist um vier Größenordnungen kleiner als jener der täglichen Sonneneinstrahlung. Die Abtrennung und Endlagerung von CO 2 (CCS) und die Umsetzung von CO 2 mit Wasserstoff zu Synthesegas (CCU) werden aus energetischer Sicht besprochen. Das „Treibhaus Erdatmosphäre“ ist ein offenes System. Das Strahlungsgleichgewicht wird als Fließgleichgewicht betrachtet, welches nach den Regeln der irreversiblen Thermodynamik zu bewerten ist.

The influence of particle size on heterogeneous equilibria is investigated using Fe clusters as an example. Considering a thermodynamic cycle, the change in free enthalpy for the transfer of an Fe atom from a dispersed system to the bulk is analyzed with the aid of experimental data from molecular beam experiments. Dissociation energies of mass-selected clusters are used for this purpose. It is shown that predictions within the framework of equilibrium thermodynamics, considering the free surface, are quantitatively correct for nanoscale clusters with less than 100 atoms. The effects on the redox behavior as well as the dependence of the work function on the cluster size are also addressed and discussed. In comparison with quantum chemical studies based on density functional theory, the simple thermodynamic model is surprisingly robust in predicting the chemical behavior of Fe in systems with reduced dimensionality.

In this present work, a biosensor built upon the triplex nanomaterial all-around gate tunnel field-effect transistor (TFET) is proposed concerning biomolecule detection. This design leverages an advanced all-around gate structure, enhancing sensitivity and selectivity in biosensing applications. Field-effect transistor (FET) biosensors offer portability and rapid, high-throughput screening capabilities, which make them particularly suitable for detecting biomarkers. The proposed 3MAG TFET biosensor includes precisely engineered nanocavities over a 1 nm gate oxide, designed to capture and detect target biomolecules efficiently. To investigate its performance, a two-dimensional simulation is conducted using technology computer-aided design (TCAD) software, enabling thorough parameter exploration. The triplex material composition contributes to low power consumption and high device sensitivity, making the biosensor a promising candidate for various biomolecular detection applications. Analytical insights were derived and validated through Sentaurus TCAD simulation results. The proposed device exhibits distinct electrical responses to biomolecules of different dielectric constants and charge states, such as DNA and proteins. Selective detection can be realized through receptor functionalization of the nanocavity surface.