Promoting near-infrared photocatalytic activity of carbon-doped carbon nitride via solid alkali activation

Ultrabroad spectral absorption is required for semiconductor photocatalysts utilized for solar-to-chemical energy conversion. The light response range can be extended by element doping, but the photocatalytic performance is generally not enhanced correspondingly. Here we present a solid alkali activation strategy to synthesize near-infrared (NIR) light-activated carbon-doped polymeric carbon nitride (A-cPCN) by combining the copolymerization of melamine and 1,3,5-trimesic acid. The prepared A-cPCN is highly crystalline with a narrowed bandgap and enhanced efficiency in the separation of photogenerated electrons and holes. Under irradiation with NIR light (780 nm >= lambda >= 700 nm), A-cPCN shows an excellent photocatalytic activity for H-2 generation from water with rate of 165 mu mol g(-1) h(-1), and the photo-redox activity for H-2 O-2 production (109 mu mol g(-1) h(-1)) from H2O and O-2, whereas no observed photocatalytic activity over pure PCN. The NIR photocatalytic activity is due to carbon doping, which leads to the formation of an interband level, and the alkali activation that achieved shrinking the transfer distance of photocarriers. The current synergistic strategy may open insights to fabricate other carbon-nitrogen-based photocatalysts for enhanced solar energy capture and conversion. (C) 2021 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

An alkali activation strategy was proposed to synthesize NIR light-activated carbon-doped polymeric carbon nitride (A-cPCN), which showed excellent photocatalytic activity under NIR light irradiation. This synergistic strategy may lead to the development of other carbon-nitrogen-based photocatalysts for enhanced solar energy conversion.