Defect Engineering of 2D Copper Tin Composite Nanosheets Realizing Promoted Electrosynthesis Performance of Hydrogen Peroxide

The transformation of the two-electron oxygen reduction reaction (2e-ORR) to produce hydrogen peroxide (H2O2) is a promising green synthesis approach that can replace the high-energy consumption anthraquinone process. However, designing and fabricating low-cost, non-precious metal electrocatalysts for 2e-ORR remains a challenge. In this study, a method of combining complexation precipitation and thermal treatment to synthesize 2D copper-tin composite nanosheets to serve as the 2e-ORR electrocatalysts is utilized, achieving a high H2O2 selectivity of 92.8% in 0.1 m KOH, and a bulk H2O2 electrosynthesis yield of 1436 mmol center dot gcat-1 center dot h-1 using a flow cell device. Remarkably, the H2O2 selectivity of this catalyst decreases by only 0.5% after 10,000 cyclic voltammetry (CV) cycles. In addition, it demonstrates that the same catalyst can achieve 97% removal of the organic pollutant methyl blue in an aqueous system solution within 1 h using the on-site degradation technology. A reasonable control of defect concentration on the 2D copper-tin composite nanosheets that can effectively improve the electrocatalytic performance is found. Density functional theory calculations confirm that the surface of the 2D copper-tin composite nanosheets is conducive to the adsorption of the key intermediate OOH*, highlighting its excellent electrocatalytic performance for ORR with high H2O2 selectivity. This finding illustrates that appropriately controlling the thermal treatment temperature of catalyst precursor can effectively regulate its oxygen vacancy defect concentration to promote the electrocatalytic ability in 2e-ORR. It is believed that the insights gained from this study pave the way for further advancements in designing high-performance nanocatalysts for the sustainable H2O2 production.image