Organic-inorganic hybrid perovskite – TiO2 nanorod arrays for efficient and stable photoelectrochemical hydrogen evolution from HI splitting

Abstract Solar-driven photoelectrochemical (PEC) hydrogen production offers a promising solution to simultaneously tackle the global energy crisis and the environmental pollution. Herein, we report a PEC cell of organic-inorganic hybrid perovskite (methylammonium lead iodide, MAPbI 3 ) - TiO 2 nanorod array (TNAs) for efficient and stable hydrogen evolution in aqueous hydrogen iodide (HI) solution. The built-in electric field created across the MAPbI 3 -TiO 2 junction is able to efficiently separate the electron-hole pairs photogenerated in MAPbI 3 with electrons quickly injected from MAPbI 3 to TiO 2 , which are then transported along the one-dimensional TiO 2 nanorod channels to the counter electrode to reduce proton to evolve hydrogen. The optimized MAPbI 3 -TNA PEC cell exhibits a high photocurrent density of 1.75 mA cm −2 at 0.14 V (vs. Ag/AgCl) under AM 1.5G illumination, which is able to stably produce molecular hydrogen at a rate of 33.3 μmol cm −2  h −1 for more than 8 h.