Bimetallic CoNi alloy nanoparticles dispersed uniformly on N-doped mesoporous hollow carbon nanospheres as efficient electrocatalysts for H2O2 production in acidic media

Abstract

The electrocatalytic two electron oxygen reduction reaction (2e^- ORR) is a promising approach to produce H₂O₂ in acidic media. However, the high cost of precious metal-based electrocatalysts and the challenge to prepare single atom catalysts with well-defined periodic structures and large metal mass content hinder their potential industrial application. We report a carbon supported bimetallic alloy nanocatalyst by dispersing CoNi alloy nanoparticles on the surface of nitrogen-doped mesoporous hollow carbon nanospheres (CoNi/N-MHCS). The CoNi/N-MHCS exhibited a superior 2e^- ORR performance with an H₂O₂ selectivity of 81 % and productivity of 6.048 mol g_cat^-1h⁻¹ in the acidic media. The catalyst also demonstrates an excellent electro-Fenton performance in degrading tetracycline hydrochloride (TCH) as a demonstration of its on-site practicability. Experiments and DFT theoretical calculations demonstrate that the charge redistribution between Co and Ni atoms due to the formation of CoNi alloy nanoparticles may reduce the reaction energy barrier of *OOH into H₂O₂, promote the reaction kinetics and modulate the adsorption energy of the intermediate *OOH on the CoNi active sites, thus enhancing the 2e^- ORR electrocatalytic performance. This work provides new insights into the development of high efficiency carbon supported bimetallic alloy catalysts for electrocatalytic conversion of O₂ into H₂O₂.