Perylenetetracarboxylic acid nanosheets with internal electric fields and anisotropic charge migration for photocatalytic hydrogen evolution

Highly efficient hydrogen evolution reactions carried out via photocatalysis using solar light remain a formidable challenge. Herein, perylenetetracarboxylic acid nanosheets with a monolayer thickness of similar to 1.5 nm were synthesized and shown to be active hydrogen evolution photocatalysts with production rates of 118.9 mmol g(-1) h(-1) The carboxyl groups increased the intensity of the internal electric fields of perylenetetracarboxylic acid from the perylene center to the carboxyl border by 10.3 times to promote charge-carrier separation. The photogenerated electrons and holes migrated to the edge and plane, respectively, to weaken charge-carrier recombination. Moreover, the perylenetetracarboxylic acid reduction potential increases from -0.47 V to -1.13 V due to the decreased molecular conjugation and enhances the reduction ability. In addition, the carboxyl groups created hydrophilic sites. This work provides a strategy to engineer the molecular structures of future efficient photocatalysts.

Automated summary

This study synthesized perylenetetracarboxylic acid nanosheets with a thickness of approximately 1.5 nm and demonstrated their activity as highly efficient hydrogen evolution photocatalysts. The introduction of carboxyl groups increased the internal electric fields, promoting charge-carrier separation, and weakened charge-carrier recombination by migrating photogenerated electrons and holes to the edge and plane, respectively. Furthermore, the reduction potential and hydrophilic sites of perylenetetracarboxylic acid were enhanced. This work provides a strategy for designing future efficient photocatalysts.