Heat treatment to prepare boron doped g-C3N4 nanodots/carbon-rich g-C3N4 nanosheets heterojunction with enhanced photocatalytic performance for water splitting hydrogen evolution

Heat treatment strategy has been initially used to prepare boron doped graphite carbon nitride nanodots (BCNDs)/carbon-rich g-C 3 N 4 nanosheets (CNS) heterojunction catalysts. The overall procedure involved three stages. First, BCNDs were prepared by the molten salt method. Next, BCNDs were dispersed onto CNS via heat treatment. Finally, the prepared heterojunction catalysts were test for photocatalytic water splitting hydrogen evolution. The experiment results show that the highest photocatalytic hydrogen evolution activity reached 6260.5 µmol·g −1 ·h −1 , which was approximately 15.7, 7.2 and 3.1 folds higher than that of bulk carbon nitride (bulk C 3 N 4 ), CNS and BCNDs/CNS-H prepared by hydrothermal method, respectively. The enhanced photocatalytic performance may be attributed to the synergistic effect of the formation of heterojunction and the increase of C content in carbon nitride. This work provides reliable guideline for the design of a novel and simple method for composite photocatalyst. • Heat treatment strategy has been initially used to prepare boron doped g-C 3 N 4 nanodots/carbon-rich g-C 3 N 4 nanosheets heterojunction catalysts. • The highest photocatalytic hydrogen precipitation activity of 3BCNDs/CNS-450 reached 6260.5 µmol·g −1 ·h −1 . • The visible light absorption and charge transfer properties of the composites are significantly enhanced. • The performance of composites prepared by heat treatment method is better than that of composites prepared by conventional hydrothermal method.