Bifunctional Pd-Ox Center at the Liquid–Solid–Gas Triphase Interface for H2O2 Photosynthesis

The coupling of H2O and O2 by solar energy is regarded as the Holy Grail reaction for a manufacturing route of H2O2; however, its efficiency has suffered from low O2 solubility in aqueous solution and difficult-to-inhibit side reactions. Herein, a liquid–solid–gas triphase system has been designed to directly utilize abundant atmospheric O2 for H2O2 photosynthesis, the most important of which is the superhydrophobic photocatalyst of amino-containing ligands combined with Pd, loaded on BiVO4 (Pd/A/BiVO4). This relatively separated catalyst and product system successfully avoids the decomposition of produced H2O2 and contributes to the accumulation of a high-concentration H2O2 solution. The enrichment of O2 and the kinetics of carriers and reaction intermediates are tunable via the interaction between Pd and amino groups, which promotes the photosynthetic yield of H2O2 to 805.9 μmol g–1 h–1 in pure water under visible illumination. During the reaction, O2 is not only converted into H2O2 as a reactant but also participates in the construction of Pd-Ox sites as a dynamic catalyst. Also, the Pd-Ox intermediate is identified as a catalytic and photoelectronic dual center. This research opens up an intriguing avenue for designing the H2O2 photosynthesis system.