High Yield Electrosynthesis of Hydrogen Peroxide from Water Using Electrospun CaSnO 3 @Carbon Fiber Membrane Catalysts with Abundant Oxygen Vacancy

Hydrogen peroxide (H 2 O 2 ) production by electrochemical two‐electron water oxidation reaction (2e‐WOR) is a promising approach, where high‐performance electrocatalysts play critical roles. Here, the synthesis of nanostructured CaSnO 3 confined in conductive carbon fiber membrane with abundant oxygen vacancy (O V ) as a new generation of 2e‐WOR electrocatalyst is reported. The CaSnO 3 @carbon fiber membrane can be directly used as a self‐standing electrode, exhibiting a record‐high H 2 O 2 production rate of 39.8 µmol cm −2  min −1 and a selectivity of ≈90% (at 2.9 V vs reversible hydrogen electrode). The CaSnO 3 @carbon fiber membrane design improves not only the electrical conductivity and stability of catalysts but also the inherent activity of CaSnO 3 . Density functional theory calculation further indicates the crucial role of O V in increasing the adsorption free energy toward oxygen intermediates associated with the competitive four‐electron water oxidation reaction pathway, thus enhancing the activity and selectivity of 2e‐WOR. The findings pave a new avenue to the rational design of electrocatalysts for H 2 O 2 production from water.