Plasma-induced hierarchical amorphous carbon nitride nanostructure with two N2C-site vacancies for photocatalytic H2O2 production

Abstract

Carbon nitride (CN) with nitrogen vacancy is a robust photocatalyst with proven enhancing H2O2 production ability. However, nitrogen vacancy control is extremely challenging with the majority of reports representing it as a few vacancies. Herein, for the first time, the amorphous CN (ACN) with two N2C-site vacancies in one CN unit is prepared by a one-step H2 plasma approach. First-principles calculations and experimental results provide consistent evidence that two N2C vacancies are located in one CN unit structure after amorphous transformation. Plasma-induced ACN is stable with a hierarchical continuous nanosheet network structure and exhibits an ultrahigh specific surface area of ~405.76 m2g−1, which is 83 times higher than that of pristine CN (4.89 m2g−1) and significantly enhanced photocatalytic H2O2 production, yielding 1874 μmolg−1h−1. Besides, the existence potential drop of 2.61 eV for the electrostatic potential in ACN is key to charge carrier separation. Moreover, the amorphous transformation leads to a new strong band tail, which remarkably enhances the absorbance edge of ACN up to 593 nm, resulting in a wider range of visible-light absorption to enhance H2O2 production. The results have provided an effective approach for promoting the practical application of ACN in photocatalytic H2O2 production.