Composite of CH 3 NH 3 PbI 3 with Reduced Graphene Oxide as a Highly Efficient and Stable Visible-Light Photocatalyst for Hydrogen Evolution in Aqueous HI Solution.

A facile and efficient photoreduction method is employed to synthesize the composite of methylammonium lead iodide perovskite (MAPbI ₃ ) with reduced graphene oxide (rGO). This MAPbI ₃ /rGO composite is shown to be an outstanding visible-light photocatalyst for H ₂ evolution in aqueous HI solution saturated with MAPbI ₃ . Powder samples of MAPbI ₃ /rGO (100 mg) show a H ₂ evolution rate of 93.9 µmol h ^-1 , which is 67 times faster than that of pristine MAPbI ₃ , 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 H ₂ evolution experiments. The electrochemiluminescence performance of MAPbI ₃ is investigated to explore the charge transfer process, to find that the photogenerated electrons in MAPbI ₃ are transferred to the rGO sites, where protons are reduced to H ₂ .
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