Lead-Free Perovskite Cs₂AgBiX₆ Nanocrystals with a Band Gap Funnel Structure for Photocatalytic CO₂ Reduction under Visible Light

Abstract

Huge potentiality of lead halide perovskite nanocrystals (NCs) can be found in optoelectronic and photocatalytic fields. However, the main bottlenecks in photocatalysis are their toxicity and instability. To shake off these issues, lead-free Cs2AgBiX6 (X = Cl, Cl0.5Br0.5, Br, Br0.5I0.5, I) double perovskite NCs were synthesized by a simple antisolvent recrystallization approach. Moreover, the as-prepared Cs2AgBiX6 materials were systematically studied for photocatalytic CO2 reduction, which costed a total electron consumption of 37.8 μmol g–1 under visible light irradiation (λ ≥ 420 nm, 300 W Xe lamp) within 3 h for Cs2AgBiI6. Our study here provides novel ideas of lead-free perovskites for photocatalytic reduction of CO2.