Introducing nitrogen vacancies is an effective method to improve the catalytic performance of g-C_(3)N_(4)-based photocatalysts,whereas understanding how nitrogen vacancies types affect the catalytic performance remai...Introducing nitrogen vacancies is an effective method to improve the catalytic performance of g-C_(3)N_(4)-based photocatalysts,whereas understanding how nitrogen vacancies types affect the catalytic performance remains unclear.Herein,two different types of nitrogen vacancies were successfully introduced into g-C_(3)N_(4)by pyrolysis of melamine under argon and ammonia atmosphere with subsequent HNO3 oxidation.The pyrolysis atmosphere is found to have a significant influence on the introduced nitrogen vacancies type,where tertiary nitrogen groups(N_(3)C)and sp2-hybridized nitrogen atoms(N_(2)C)were the preferred sites for the formation of nitrogen vacancies under ammonia and argon pyrolysis,respectively.Moreover,nitrogen vacancies from N3C are experimentally and theoretically demonstrated to facilitate the narrowed band gap and the improved oxygen absorption capability.As expected,the optimal catalyst exhibits high H_(2)O_(2)yield of 451.8µM,which is 3.8 times higher than the pristine g-C_(3)N_(4)(119.0µM)after 4 h and good stability after10 photocatalytic runs.展开更多
基金Huxiang High-Level Talent Gathering Project of Hunan Province,Grant/Award Number:2019RS1012Natural Science Foundation of Changsha,Grant/Award Number:KQ2202146Fundamental Research Funds for the Central Universities,Grant/Award Numbers:531118010232,202044011。
文摘Introducing nitrogen vacancies is an effective method to improve the catalytic performance of g-C_(3)N_(4)-based photocatalysts,whereas understanding how nitrogen vacancies types affect the catalytic performance remains unclear.Herein,two different types of nitrogen vacancies were successfully introduced into g-C_(3)N_(4)by pyrolysis of melamine under argon and ammonia atmosphere with subsequent HNO3 oxidation.The pyrolysis atmosphere is found to have a significant influence on the introduced nitrogen vacancies type,where tertiary nitrogen groups(N_(3)C)and sp2-hybridized nitrogen atoms(N_(2)C)were the preferred sites for the formation of nitrogen vacancies under ammonia and argon pyrolysis,respectively.Moreover,nitrogen vacancies from N3C are experimentally and theoretically demonstrated to facilitate the narrowed band gap and the improved oxygen absorption capability.As expected,the optimal catalyst exhibits high H_(2)O_(2)yield of 451.8µM,which is 3.8 times higher than the pristine g-C_(3)N_(4)(119.0µM)after 4 h and good stability after10 photocatalytic runs.
