An Efficient Photocatalytic Process for Hydrogen Production and Acetic Acid Synthesis on FAPbBr ₃ Perovskite

ABSTRACT 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 H 2 evolution and oxidative upgrading of acetaldehyde to valuable acetic acid. Using a Pt single‐atom‐modified FAPbBr 3 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 H 2 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.