Bias-Free Photoelectrochemical H2O2 Production and Its In Situ Applications

Hydrogen peroxide (H 2 O 2 ) is a valuable chemical that has been used in a wide range of applications. Currently, H 2 O 2 production relies predominantly on the anthraquinone process, which is energy-intensive and non-ecofriendly. The photoelectrochemical two-electron O 2 reduction reaction (2e – ORR) and 2e – water oxidation reaction (2e – WOR) have recently emerged as promising alternatives to produce H 2 O 2 in a bias-free, cost-effective, and environmentally benign manner. In this Perspective, we overview photoelectrochemical routes to H 2 O 2 production and its in situ application for valuable chemical synthesis. We discuss the design principles needed for achieving a bias-free photoelectrochemical H 2 O 2 synthesis and introduce the concept of single and dual constructions, with notable examples of each one. We benchmark the solar-to-chemical conversion efficiencies of photoelectr…