Defect-induced Zn–Co pair active site for high-efficiency electrosynthesis of H2O2

Given the trade-off between activity and selectivity, typical pure CoSe 2 catalyst that excels in the initial proton-coupled electron transfer, however, usually underperforms in the subsequent reaction process, leading to low performance for acidic 2e − oxygen reduction reaction (ORR) to H 2 O 2 . Here, we report a class of Zn–Co pair active sites on the defected CoSe 2- x . The Zn–Co pair active site can well modulate electronic structure for enhancing the adsorption and activation of ∗O 2 to achieve high-selectivity electrosynthesis of H 2 O 2 . The surrounding Co site has the optimal Gibbs free energy for ∗OOH because of the d-p orbital hybridization between the near-end O (∗OOH) and Co near the Fermi level. The Zn 1 -Co/CoSe 2- x catalyst achieves high selectivity of 95% under 0 V against a reversible hydrogen electrode (RHE) and the maximum productivity of 2.26 mol g cat. −1 h −1 at 250 mA cm −2 , which is among the best non-noble metal-based compound catalysts in an acidic medium.