Dual P-Doped-Site Modified Porous G-C3n4 Achieves High Dissociation and Mobility Efficiency for Photocatalytic H2o2 Production

Abstract

Organic semiconductor under photoexcitation could generate abundant strong-binding Frenkel excitons and inevitably suffer from low dissociation efficiency (˂1%) and poor mobility ability, which severely suppresses the efficient utilization of photogenerated charges and corresponding activity. Herein, a dual P-doping strategy is proposed in bay and corner sites implanted polymeric carbon nitride (PCN-D) for visible-driven H2O2 production. The dual P doping breaks localized electron state around original symmetric heptazine units and weakens the binding energy between electrons and holes, increasing dissociation efficiency to reach 11.9% with 20-fold improvement. In addition, the conductivity ability of PCN-D, including formed carrier charge concentration and mobility, achieves 13-fold and 7-fold improvement, which facilitates the charge transfer and separation. The proposed dual doped-P-site strategy, with the blessing of porous structure, provides plentiful active center for effective adsorption and activation of O2 molecule, further accelerating reaction progress and achieving six-times increase of photocatalytic H2O2 production rate. This work provides in-depth insight into the importance of dual P-doping to optimize kinetic behavior of photogenerated charges and opens an avenue to the multiscale doping-modulation of semiconductor with high efficiency solar energy conversion.

Keywords: Dissociation, Mobility, Carbon nitride (g-C3N4), Photocatalysis, H2O2 production