Selective CO2 hydrogenation to formic acid over a novel Ga-Sn-Ce ternary catalyst

Electrodeposition is a simple and rapid method for the preparation of thin-film materials, allowing catalytic materials to be directly deposited onto substrates, thereby eliminating the need for binders. Compared with bulk materials, two-dimensional thin films possess a higher specific surface area. The incorporation of Ga in Sn-based alloy materials can effectively expose active sites, thereby enhancing the catalytic performance for CO 2 electroreduction. Doping with rare-earth elements such as cerium can induce the formation of oxygen vacancies and defect sites, or modulate the electronic structure of the catalyst surface. These modifications enable independent regulation of the adsorption energy of various intermediates, effectively lowering reaction energy barriers and improving catalytic efficiency. In this work, Ga-Sn-Ce electrodes were synthesized via electrodeposition in a deep eutectic solvent composed of choline chloride and urea, and subsequently applied to CO 2 reduction. The GaSnCe0.6 electrode exhibited excellent selectivity toward formic acid at −0.99 V vs. the reversible hydrogen electrode, achieving a Faradaic efficiency of 92 %. Compared with previously reported Ga-Sn alloys, the introduction of Ce resulted in a positive shift of 250–270 mV in the optimal reduction potential for formic acid production from CO 2 .