Electrochemical deposition of Ni-Co oxides vs. low-temperature hollow cathode plasma jet sputtering on stainless steel meshes: Physicochemical properties and activity in volatile organic compounds oxidation

Volatile organic compounds in the air are a health problem for the human population. Air oxidation in the presence of catalysts is successfully used to remove them. Precious metal-based catalysts are successfully replaced by transition metal oxide-based catalysts. Reducing the cost of catalysts can be achieved through new preparation processes that minimize the amount of catalyst required.

The study compares three methods for preparing nickel-cobalt oxide catalysts on stainless steel meshes for the oxidation of volatile organic compounds (VOC) such as ethanol and toluene: (i) electrochemical deposition followed by calcination in air, (ii) plasma jet sputtering using a hollow Ni-Co alloy cathode in an oxidation Ar+O₂ atmosphere, and (iii) a combination of both foregoing methods.  Characterization of the catalysts confirmed the formation of Ni-Co spinel and NiO phases in all samples. Catalysts prepared by plasma jet sputtering exhibited higher catalytic activity, attributed to finer oxide particles, increased surface Co concentration, and a higher density of oxygen vacancies. Electrochemically deposited catalysts showed low activity due to the presence of larger oxide particles and a low surface area. The highest catalytic performance was achieved by plasma-sputtering Ni-Co oxide onto an electrochemically deposited oxide layer, combining the advantages of both methods. These results highlight the potential of plasma jet sputtering to produce highly active Ni-Co oxide catalysts with minimal active material loading.

This study was conducted as part of the cooperation between the Research Group of Catalysis and Reaction Engineering and the Research Group of Laser Chemistry of the Institute of Chemical Process Fundamentals of the CAS, the Institute of Physics of the CAS, and the University of Chemistry and Technology in Prague.

• Jirátová K., Naiko I., Ostapenko A., Olejníček J., Čada M., Balabánová J., Koštejn M., Maixner J., Topka P., Kovanda F.: Electrochemical deposition of Ni-Co oxides vs. low-temperature hollow cathode plasma jet sputtering on stainless steel meshes: Physicochemical properties and activity in volatile organic compounds oxidation. Surf. Coat. Technol. 2026, 520(15 Jan), 133068. doi.org/10.1016/j.surfcoat.2025.133068