Plasma-induced hierarchical amorphous carbon nitride nanostructure with two N2 C-site vacancies for photocatalytic H2O2 production

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 N-2 C-site vacancies in one CN unit is prepared by a one-step H-2 plasma approach. First-principles calculations , experimental results provide consistent evidence that two N-2 C 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 ul-trahigh specific surface area of ~405.76 m(2)g(-1), which is 83 times higher than that of pristine CN (4.89 m(2)g(-1)) and significantly enhanced photocatalytic H2O2 production, yielding 1874 mu molg(-1)h(-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.

Automated summary

Amorphous carbon nitride (ACN) with two nitrogen vacancy sites in one CN unit has been successfully prepared using a one-step H2 plasma approach. The ACN material exhibits a stable network structure, high specific surface area, and enhanced photocatalytic H2O2 production. The presence of an electrostatic potential drop and a new strong band tail in ACN contribute to improved charge carrier separation and enhanced visible-light absorption.