High visible-light photocatalytic performance of stable lead-free Cs2AgBiBr6 double perovskite nanocrystals

Lead halide perovskite nanocrystals (NCs) have been recognized as a rather competitive candidates for potential advanced optoelectronic applications. But the toxicity of lead and the intrinsic instability are the key concerns for their large-scale commercialization. For addressing these tricky issues, we synthesized lead-free all-inorganic Cs2AgBiBr6 double perovskite NCs adopting a facile hot injection approach. The as-prepared NCs could keep their structure stable either in air for more than two months or being heated at 300 °C in ambient atmosphere for 3 h. Moreover, Cs2AgBiBr6 NCs were investigated for photocatalytic NO removal under visible-light irradiation, achieving an exciting removal rate of 97%, which is much higher than the previous reports as we know. In addition, the Cs2AgBiBr6 NCs demonstrated outstanding recyclability for at least four cycles in NO removal. The photocatalytic mechanism of Cs2AgBiBr6 NCs was further proposed. This investigation offers a new environmental photocatalyst to purify the air.