Composite of CH3NH3PbI3 with Reduced Graphene Oxide as a Highly Efficient and Stable Visible-Light Photocatalyst for Hydrogen Evolution in Aqueous HI Solution

Abstract

A facile and efficient photoreduction method is employed to synthesize the composite of methylammonium lead iodide perovskite (MAPbI₃) with reduced graphene oxide (rGO). This MAPbI₃/rGO composite is shown to be an outstanding visible-light photocatalyst for H₂ evolution in aqueous HI solution saturated with MAPbI₃. Powder samples of MAPbI₃/rGO (100 mg) show a H₂ evolution rate of 93.9 µmol h⁻¹, which is 67 times faster than that of pristine MAPbI₃, under 120 mW cm⁻² visible-light (λ ≥ 420 nm) illumination, and the composite is highly stable showing no significant decrease in the catalytic activity after 200 h (i.e., 20 cycles) of repeated H₂ evolution experiments. The electrochemiluminescence performance of MAPbI₃ is investigated to explore the charge transfer process, to find that the photogenerated electrons in MAPbI₃ are transferred to the rGO sites, where protons are reduced to H₂.

Through compositing with photoreduced graphene oxide (rGO), the photocatalytic hydrogen evolution activity of CH₃NH₃PbI₃ is greatly elevated by a factor of 67 (93.9 µmol h⁻¹ with 100 mg initial amount, λ ≥ 420 nm, 120 mW cm⁻²), making the CH₃NH₃PbI₃/rGO composite an efficient and stable visible-light photocatalyst in aqueous HI solution saturated with MAPbI₃.

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