Coupling Selective Organic Oxidation With Hydrogen Evolution Over Metal Halide Perovskite Photocatalysts: Halide‐Dependent Design, Mechanisms, and Stability Challenges

ABSTRACT Metal halide perovskites (MHPs) have recently emerged as a versatile class of photocatalysts capable of mediating selective organic oxidation reactions while simultaneously driving hydrogen () evolution under mild visible‐light illumination. Their strong visible‐light absorption and tuneable band structures enable efficient generation and spatial separation of photogenerated charge carriers, driving the selective oxidation of organic molecules such as alcohols, amines, and carboxylic acids while simultaneously promoting production. This dual‐function strategy replaces the kinetically demanding oxygen evolution reaction (OER) with thermodynamically and kinetically more accessible organic oxidation pathways, simultaneously generating value‐added chemical products and clean fuel. Across chloride‐ (Cl‐), bromide‐ (Br‐), and iodide‐(I‐) based compositions, halide identity governs a trade‐off between visible‐light absorption and structural stability, whereas surface and interfacial engineering strategies including heterojunction formation, halide alloying, ligand passivation, and core–shell encapsulation have been developed to enhance charge extraction and suppress lattice degradation under operating conditions. This review critically examines these halide‐dependent design principles and surface engineering strategies, situates them within the mechanistic context of representative alcohol, amine, and carboxylic acid oxidation reactions and evaluates the structural stability challenges that arise from polar substrates, reactive intermediates, and moisture exposure. By integrating advances in perovskite chemistry with mechanistic understanding of coupled photocatalytic oxidation and evolution reaction (HER)