Rigid Confinement and Interfacial Electronic Polarization Enable Highly Selective SiO2@C/Sn Catalysts for Two-Electron Oxygen Reduction Toward Efficient H2O2 Production

The two-electron oxygen reduction reaction (2e − ORR) provides a sustainable route for green hydrogen peroxide (H 2 O 2 ) synthesis, but the development of p -block metal catalysts that combine high activity with long-term stability remains challenging. Herein, we propose a hierarchical core-shell catalyst, SiO 2 @C/Sn. Mesoporous silicon dioxide (SiO 2 ) serves as a rigid confinement scaffold to effectively suppress the migration and aggregation of Sn nanoparticles. Simultaneously, a conductive carbon layer was in-situ formed on the SiO 2 surface, markedly enhancing interfacial charge transport. Importantly, the interfacial electronic structure of the Sn nanoparticles is moderately tuned by the combined effect of SiO 2 confinement and the continuous electronic interface provided by the carbon layer, thereby maintaining an optimal adsorption-desorption balance for the *OOH intermediate and significantly improving selectivity toward the 2e − pathway. SiO 2 @C/Sn achieves H 2 O 2 selectivity exceeding 97% and a production rate of 16.15 mol·g − 1 ·h − 1 in alkaline media, while 80% selectivity with a yield of 8.13 mol·g − 1 ·h − 1 in neutral media. The catalytic activity shows almost no decay after 100 h of continuous operation. In-situ spectroscopies combined with DFT calculations further reveal that polarization coupling at the SiO 2 -carbon interface induces electronic redistribution that optimizes the electronic states of Sn sites and thereby stabilizes the 2e − reaction pathway.