Deposited thin-film nanoelectrocatalysts of non-noble metals for co-capture of CO₂ and reduction of nitrates

Introduction. The co-electrolysis of nitrate and CO₂ can contribute to urea production with low carbon-oxide emission rate, and at the same time can reduce NO₃^- to extremely low permissible concentrations. The synthesis of thin-layer nanoelectrocatalysts containing transition-metal nanoparticles is a promising venture. The study proposes the use of precipitated electrocatalysts from base metals. Such a method makes it possible to obtain an electrocatalyst selective to the reduction reaction of CO₂ or NO₃^-, and their joint reduction product is urea. The electrocatalyst coating should firmly bind C-N, and can proceed with the formation of intermediate compounds (such as *CONH₂) and others.

Experimental. The materials for the electrocatalyst were synthesized by the authors, and characterized using the methods of SEM, XPS, and DRS. The electrochemical methods of voltammetry, chronoamperometry, electrochemical double-layer capacity, and electrochemical impedance spectroscopy were used in this work.

Results and Discussion. In this study, a selective thin-layer electrocatalyst is to be synthesized and used for the reaction of CO₂ and NO₃^- binding and their conversion to urea. The reaction will be carried out using electrochemical reduction under galvanostatic and potentiostatic conditions. As a result, the rate of synthesis of the target product will be determined and the Faraday efficiency of the process will be calculated. The unique electronic structure of transition metals allows them to be active catalysts in the co-reduction reaction of nitrate and carbon dioxide. The choice of metal or different combinations of components in bimetallic catalysts, as well as exploring the conditions of electrochemical synthesis, may allow us to improve the kinetics of the process and increase the selectivity of the process.

Acknowledgment. The authors acknowledge support from Lomonosov Moscow State University Program of Development for providing access to the EIS facilities. The authors express their acknowledgements to the Russian National Research Project No. AAAAA-A21–122040600057–3.