Unveiling the dynamic interface evolution co-induced by cations and vacancies for boosted in situ hydrogen peroxide...

Recently, the cation-induced interface modulation in electrocatalytic hydrogen peroxide (H₂O₂) synthesis has garnered significant interest. However, the insufficient comprehension of the coupling effect of the cations and catalysts in optimizing the interface microenvironment has inhibited the further development of H₂O₂ electrosynthesis. Here, we represent a two-stage mechanism wherein defect-driven "cation trapping" initiates interfacial restructuring, dynamically optimizing the microenvironment to achieve H₂O₂ selectivity improvement. By integrating ab initio molecular dynamics (AIMD) simulations, it demonstrated the presence of carbon vacancies (CV) enabling the spontaneous barrier-less adsorption of Na⁺ at the interface (Stage-I). Moreover, the results of in situ Raman and theoretical calculations proved that the CV configuration combined with Na⁺ ions served as the prominent site, benefiting the generation of *OOH subsequently (Stage-II). And the Na⁺ triggered electronic modulation effect effectively suppresses the occurrence of side reactions, which boosts the H₂O₂ electrosynthesis. This work emphasized the cooperation of cations and catalysts, which was beneficial for further realizing the regulation of electrocatalytic interface environment.