Decoration of Ag nanoparticles on CoMoO₄ rods for efficient electrochemical reduction of CO₂

Hydrothermal and photoreduction/deposition methods were used to fabricate Ag nanoparticles (NPs) decorated CoMoO₄ rods. Improvement of charge transfer and transportation of ions by making heterostructure was proved by cyclic voltammetry and electrochemical impedance spectroscopy measurements. Linear sweep voltammetry results revealed a fivefold enhancement of current density by fabricating heterostructure. The lowest Tafel slope (112 mV/dec) for heterostructure compared with CoMoO₄ (273 mV/dec) suggested the improvement of electrocatalytic performance. The electrochemical CO₂ reduction reaction was performed on an H-type cell. The CoMoO₄ electrocatalyst possessed the Faraday efficiencies (FEs) of CO and CH₄ up to 56.80% and 19.80%, respectively at  - 1.3 V versus RHE. In addition, Ag NPs decorated CoMoO₄ electrocatalyst showed FEs for CO, CH₄, and C₂H₆ were 35.30%, 11.40%, and 44.20%, respectively, at the same potential. It is found that CO₂ reduction products shifted from CO/CH₄ to C₂H₆ when the Ag NPs deposited on the CoMoO₄ electrocatalyst. In addition, it demonstrated excellent electrocatalytic stability after a prolonged 25 h amperometric test at  - 1.3 V versus RHE. It can be attributed to a synergistic effect between the Ag NPs and CoMoO₄ rods. This study highlights the cooperation between Ag NPs on CoMoO₄ components and provides new insight into the design of heterostructure as an efficient, stable catalyst towards electrocatalytic reduction of CO₂ to CO, CH₄, and C₂H₆ products.