An Efficient Photocatalytic Process for Hydrogen Production and Acetic Acid Synthesis on FAPbBr₃ Perovskite

Perovskite-based photocatalytic hydrogen bromide (HBr) splitting offers a promising route for solar-driven hydrogen production. However, the accumulation of the oxidation product bromine often impedes reaction kinetics due to its sluggish oxidation, which faces a substantial energy barrier of 1.09 V versus NHE. This study introduces acetaldehyde as a stable and highly reductive agent in a perovskite-saturated HBr system, enabling simultaneous high-performance H₂ evolution and oxidative upgrading of acetaldehyde to valuable acetic acid. Using a Pt single-atom-modified FAPbBr₃ perovskite with exposed (100) and (111) facets, which is different from the traditional morphology of perovskites and provides efficient charge separation, the system achieves remarkable production rates of 1033.13 µmol h^-1 for H₂ and 1017.20 µmol h^-1 for acetic acid. High apparent quantum efficiencies of 30.62% at 450 nm and 31.78% at 520 nm are attained, with acetaldehyde conversion exceeding 90%. The process demonstrates stability over 15 h, recovering 0.8 mL of acetic acid at an 85% extraction efficiency. This strategy effectively utilizes both electrons and holes to simultaneously produce clean energy hydrogen and high-value organic products.