In Situ Synthesis of Lead-Free Halide Perovskite Cs₂AgBiBr₆ Supported on Nitrogen-Doped Carbon for Efficient Hydrogen...

Lead halide perovskites have shown great potential in photovoltaic and photocatalytic fields. However, the toxicity of lead impedes their wide application. Herein composites of lead-free halide perovskite Cs₂AgBiBr₆ supported on nitrogen-doped carbon (N-C) materials were synthesized successfully through a facile one-pot method for the first time. Without deposition of noble metals as the cocatalyst, the optimal composite Cs₂AgBiBr₆/N-C (Cs₂AgBiBr₆/N-C-140) exhibits outstanding photocatalytic performance with a high hydrogen evolution rate of 380 μmol g^-1 h^-1 under visible light irradiation (λ ≥ 420 nm), which is about 19 times faster than that of pure Cs₂AgBiBr₆ and 4 times faster than that of physically mixed Cs₂AgBiBr₆/N-C-140, respectively. The Cs₂AgBiBr₆/N-C-140 composite also displays high stability with no significant decrease after six cycles of repeated hydrogen evolution experiments. The addition of N-C with a high surface area helps to prevent aggregation of Cs₂AgBiBr₆ NPs and provides more pathways for the migration of photoinduced carriers. The nitrogen dopant can facilitate photoinduced electron transfer from Cs₂AgBiBr₆ to N-C to result in spatially separated electrons and holes with prolonged electron time and greatly enhance the photocatalytic performance. This study indicates that Cs₂AgBiBr₆-based perovskite materials are promising candidates for photocatalytic hydrogen evolution.