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

Electrochemical hydrogen peroxide (H 2 O 2 ) synthesis from water and air via two-electron (2e − ) water oxidation or oxygen reduction reactions could provide a sustainable route for on-site H 2 O 2 production. Unfortunately, the electrochemical H 2 O-to-H 2 O 2 process usually suffers from limited selectivity under high current density. Here, we present an atomic Ni-doped TiO 2 electrocatalyst that enables H 2 O 2 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 H 2 O 2 is achieved at 240 mA in a full flow cell device. Moreover, this device could be operated for modular H 2 O 2 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 H 2 O to H 2 O 2 and the practical applicability for the on-site H 2 O 2 production from earth-abundant resources.