Halide Perovskite Integrated Photovoltaic Cathodes Incorporating Pt on ZIF‐8‐Derived Carbon for Solar Hydrogen Production

ABSTRACT Advancing solar‐driven hydrogen production in compact, integrated devices requires the development of highly active catalysts with minimal precious‐metal loading, alongside light absorbers capable of stable operation in aqueous environments. Here, we report an integrated halide perovskite photovoltaic cathode incorporating a low‐Pt‐content catalyst supported on zeolitic imidazolate framework‐8 (ZIF‐8)‐derived carbon and a self‐adhesive graphite sheet. The ZIF‐8‐derived carbon, featuring high porosity and surface functional groups from carbonization, enables uniform dispersion of Pt nanoparticles, enhances active‐site accessibility, and ensures stability under acidic conditions. As a result, the Pt loading is reduced by an order of magnitude (to 5.60 µg Pt cm −2 ) while surpassing the catalytic performance of commercial C/Pt (16.0 vs. 26.3 mV overpotential at 10 mA cm −2 ). The laminated graphite sheet efficiently conducts photoinduced electrons from the photovoltaic layer to the catalyst, provides mechanical support, and prevents electrolyte penetration into the perovskite layers. The resulting monolithic integrated photovoltaic cathode achieves an average photocurrent density of 19.8 mA cm −2 at 0.0 V RHE and retains 77% of its initial performance after 160 h of continuous operation in acidic media. These results demonstrate that combining porous carbon‐supported low‐Pt catalysts with a simple graphite‐sheet protection strategy offers a scalable and cost‐effective pathway toward durable halide perovskite‐based solar hydrogen generation.