Enhanced photocatalytic hydrogen production performance of g-C3N4 with rich carbon vacancies

Abstract

Hydrogen energy is globally recognized as one of the clean and renewable chemical energy sources. Development of photocatalysts that can efficiently utilize sunlight for photocatalytic hydrogen production is an urgent mission at present. In this study, g-C3N4 with abundant pore structure and carbon defects for photocatalytic hydrogen generation was prepared by heat treatment of g-C3N4 using ammonium carbonate. The results of photocatalytic hydrogen evolution experiments demonstrate that the 5NHC sample (2 g g-C3N4 was mixed with 5.0 g ammonium carbonate) exhibits the highest hydrogen precipitation rate (972.3 μmol g-1h−1), which is 4.29 times higher than that of the reference g-C3N4 (183.6 μmol g-1h−1). Moreover, the 5NHC sample shows excellent structural stability during the hydrogen production cycling experiments, confirmed by the experimental results. Cr(VI) reduction results further demonstrate excellent photocatalytic performance of 5NHC, which is 1.54 times higher than that of the reference g-C3N4. The defective energy levels induced by carbon vacancies will lead to a rapid separation of photoinduced charge pairs, which will result in boosted photocatalytic performance. This work provides an effective strategy for development of highly performance g-C3N4.