With regard to using the electric energy generated by renewable sources, the CO₂ electroreduction reaction (CO₂RR) for the production of fuels is helpful for creating an artificial carbon cycle.

Electrochemical conversion of CO₂ into useful fuels provides tremendous potential for renewable energy storage. This study investigated a predominant nanostructure-dependent catalytic electroreduction of CO₂ into formate on Bi₂O₃ electrode in 0.5 M KHCO₃ electrolyte. Compared with nano-particle Bi catalyst derived from Bi₂O₃ nanorods (Bi₂O₃-R) electrode, the nano-flowered Bi in situ prepared via reduction of etched Bi₂O₃ nanorods (Bi₂O₃-E) exhibited an enhanced catalytic activity for CO₂ electroreduction to formate. A relatively low overpotential of 530 mV was observed over Bi₂O₃-E electrode for formate generation, and the maximum faradaic efficiency (FE) was achieved 99.2% at −1.5 V vs SCE with operating at a current density of 7.5 mA cm⁻², which was superior to that of Bi₂O₃-R (FE = 67.9%). Experimental results revealed that the electrochemical active surface area and catalytic activity over reduced Bi₂O₃-E electrode were originated from the nano-flowered structure with abundant edge sites. The durability of catalytic activity over Bi₂O₃-E lasted at least for 20 h of continuous reaction with negligible decline of FE and current density. This insight may benefit for the further design of surface morphology and structure devoting to improving the catalytic efficiency for CO₂ electroreduction.

The application of monolithic coated catalysts to NO _x abatement is a crucial issue for practical applications to enhance the mechanical strength, economize the cost, facilitate recycling etc ., compared with the conventional monolithic extrusive catalysts.

We highlights the importance of surface evolution by electrochemical pre-treatment while stabilizing the main body of the catalyst. The PANi/CuBi₂O₄via electro-chemical activation process shows high faraday efficiency to ethanol.

The electro-reduction of CO ₂ to produce energy sources has been considered as a visionary pathway with the help of renewable electricity, which can achieve carbon neutrality and mitigate global warming.