Infrared-to-visible energy transfer photocatalysis over black phosphorus quantum dots/carbon nitride

Abstract

• BP QDs decorated hollow S doping carbon nitride nanospheres are synthesized. • The hollow porous structures generate more active sites for photocatalytic reaction. • BP/S-HC 3 N 4 exhibits remarkable photocatalytic amino acids and H 2 production rates. • The charge separation and exciton–exciton energy transfer are greatly promoted. Polymeric photocatalysts have been considered as promising candidates for the photocatalytic biomass conversion and H 2 evolution, but they suffer from the fast charge recombination and the short light absorption range. Herein, for the first time, a novel energy-transfer-mediated photocatalyst is facilely fabricated by anchoring black phosphorus quantum dots on sulfur-doped graphitic carbon nitride hollow nanospheres (BP/S-HC 3 N 4 ). Doping of S element not only inhibits the recombination of photogenerated carriers, but also promote exciton dissociation by trap states. In addition, black phosphorus quantum dots extend the light response range to the near-infrared region, and the near-infrared light energy can be transferred to S-HC 3 N 4 through exciton mediated energy transfer, so as to improve the photocatalytic performance, and this energy transfer mechanism is not limited by the heterojunction type Ⅰ energy band structure. In this conceptual photocatalytic system, energy transfer is different from the traditional carrier transfer mechanism, which is not restricted by the energy band structure. Consequently, the photocatalytic amino acids and hydrogen production rates of BP/S-HC 3 N 4 reach 643 mmol h −1 and 102 μmol h −1 under visible-NIR light, which are 58.5 and 51.0 times larger than that of the pristine g-C 3 N 4 , respectively. This work provides a new strategy for constructing high-efficient and wide-spectral response photocatalysts.