Abstract:
Bismuth (Bi) and indium (In) metals are potential catalysts for the production of formic acid in the electrocatalytic CO
2 reduction reaction (CO
2RR), but their activity and stability are insufficient, which limits their application in practice. Based on this, bimetallic catalysts were constructed using Bi and In metals. A series of BiIn-x alloy catalysts were prepared by reducing metal salts of different mass ratios. With the addition of indium salt, Bi nanosheets were transformed into nanosheet assembly structures. BiIn bimetallic catalyst (BiIn-0.06) with three-dimensional porous honeycomb structure assembled by tiny nanosheets was obtained when the amount of indium salt added is 6% mass ratio. This three-dimensional porous honeycomb structure facilitates the transport of electrons and reactants. The catalyst has more surface active sites, and the two metal elements work together to optimize and accelerate the chemical reaction, improving the generation efficiency of the target product. At an electrode potential of −1.0 V
RHE, BiIn-0.06 achieved a maximum FE
HCOOH of 96.97% and HCOOH partial current density of 31.9 mA /cm
2, and within a potential range of −0.8 to −0.1 V
RHE, its FE
HCOOH remained above 91%. The results indicate that varying In doping levels can alter the crystal structure and surface morphology of Bi-based alloy catalysts, promote the adsorption of reaction intermediates, and significantly enhance CO
2RR activity and product selectivity.