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 mmol 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.

Automated summary

This study presents an atomic Ni-doped TiO2 electrocatalyst for efficient synthesis of H2O2 through 2e- water oxidation. By combining with the 2e- oxygen reduction reaction using an oxidized carbon nanotube cathode, a high Faradaic efficiency of 146% for H2O2 is achieved. This work demonstrates the potential of atomically controlled metal oxide electrocatalyst for on-site H2O2 production.