Prospects and Promises in Two-Electron Water Oxidation for Hydrogen Peroxide Generation

A key oxidizing agent for the chemical industry, wastewater treatment, and semiconductor development is hydrogen peroxide (H 2 O 2 ). Electrochemical (EC) and photoelectrochemical (PEC) production of H 2 O 2 syntheses have been studied as promising alternatives to the unsustainable anthraquinone oxidation process and the H 2 and O 2 direct gas synthesis route. While cathodic O 2 reduction to produce H 2 O 2 draws more extensive attention than anodic water oxidation due to the higher obtained indicator of Faraday efficiency and production rate of H 2 O 2, however, in the long term, using water as a raw material for water oxidation is a desirable procedure for the sustainable development of H 2 O 2 production. To inspire innovative ideas for boosting the H 2 O 2 yield in photo/electrocatalysis, we review recent advancements in EC/PEC H 2 O 2 production from experimental and computational points of view. The fundamental mechanism of the process, rational design of the electrode, and advanced engineering strategies for enhancement of H 2 O 2 production via a two-electron water oxidation reaction (2e – WOR) are thoroughly summarized. Furthermore, we discuss the hindrances and challenges of 2e – WOR, including all intermediates and competing reaction routes, integrate tandem device development, and the H 2 O 2 degradation issues for better addressing. 2e – WOR enables more excellent H 2 O 2 production rates with optimal efficiency.