Highly efficient paired H2O2 production through 2e− water oxidation coupled with 2e− oxygen reduction

Electrochemical hydrogen peroxide (H2O2) synthesis from water and air via two-electron (2e−) water oxidation or oxygen reduction reactions could provide a sustainable route for on-site H2O2 production. Unfortunately, the electrochemical H2O-to-H2O2 process usually suffers from limited selectivity under high current density. Here, we present an atomic Ni-doped TiO2 electrocatalyst that enables H2O2 production through 2e− water oxidation with high Faradaic efficiency of 70% at ∼300 mA cm−2. Furthermore, when paired with the 2e− oxygen reduction reaction using the oxidized carbon nanotube cathode, as high as 146% Faradaic efficiency for H2O2 is achieved at 240 mA in a full flow cell device. Moreover, this device could be operated for modular H2O2 synthesis with a production rate of 109.12 μmol min−1 (i.e., 3.7 mg min−1). This work demonstrates the atomically controlled metal oxide electrocatalyst for harsh anodic H2O to H2O2 and the practical applicability for the on-site H2O2 production from earth-abundant resources.