Dynamic Interaction between Methylammonium Lead Iodide and TiO₂ Nanocrystals Leads to Enhanced Photocatalytic H₂ Evolution from HI Splitting

Organic–inorganic hybrid perovskites have been extensively investigated for solar-to-electricity transformation because of their excellent optoelectronic properties. However, these materials have been rarely pursued as photocatalysts for solar-to-fuel conversion because of their intolerance to water and lack of efficient strategies to promote charge transportation in the nanoscale domain. Herein, Pt/TiO2 nanoparticles, which act as temporary reservoirs for accommodating methylammonium lead iodide (MAPbI3), were hybridized with MAPbI3, creating dynamically existing electron-transporting channels between the two components. As a consequence, the charge transportation efficiency for MAPbI3 nanoparticles was drastically enhanced and the rate of photocatalytic hydrogen evolution from HI splitting was increased by ca. 89 times compared with that of Pt/MAPbI3. An apparent quantum efficiency of ca. 70% for H2 evolution at 420 nm and a solar-to-chemical conversion efficiency of ca. 0.86% were obtained.