InBi Bimetallic Sites for Efficient Electrochemical Reduction of CO₂ to HCOOH

Formic acid is receiving intensive attention as being one of the most progressive chemical fuels for the electrochemical reduction of carbon dioxide. However, the majority of catalysts suffer from low current density and Faraday efficiency. To this end, an efficient catalyst of In/Bi-750 with InO_x nanodots load is prepared on a two-dimensional nanoflake Bi₂ O₂ CO₃ substrate, which increases the adsorption of ^* CO₂ due to the synergistic interaction between the bimetals and the exposure of sufficient active sites. In the H-type electrolytic cell, the formate Faraday efficiency (FE) reaches 97.17% at -1.0 V (vs reversible hydrogen electrode (RHE)) with no significant decay over 48 h. A formate Faraday efficiency of 90.83% is also obtained in the flow cell at a higher current density of 200 mA cm^-2 . Both in-situ Fourier transform infrared spectroscopy (FT-IR) and theoretical calculations show that the BiIn bimetallic site can deliver superior binding energy to the ^* OCHO intermediate, thereby fundamentally accelerating the conversion of CO₂ to HCOOH. Furthermore, assembled Zn-CO₂ cell exhibits a maximum power of 6.97 mW cm^-1 and a stability of 60 h.