Abstract
Poor optical absorbance and charge recombination are the major drawbacks of polymeric graphitic carbon nitride (g-C 3 N 4 )-based photocatalysts. In this paper, we show for the first time a single-step in situ technique to control the porosity of two-dimensional g-C 3 N 4 sheets and exfoliate them by introducing ascorbic acid (AA) molecules. The AA simultaneously acts as the carbon (C) source and deposits amorphous C onto g-C 3 N 4 sheets. Nanosized pores are also introduced into the g-C 3 N 4 sheets, leading to a large number of active sites. The as-prepared C-doped porous g-C 3 N 4 nanosheets demonstrate a high visible light-photocatalytic H 2 production activity of 793 μmol g -1 with the optimum structure, which is almost 25 times higher than the value obtained with bulk g-C 3 N 4 (31 μmol g -1 ). This exceptional photocatalytic performance arises from the C-doped conjugated system and porous nanosheets. The enhanced photocatalytic H 2 evolution was attributed to the effective separation and transport of charge carriers by the deposition of C onto the nanosheets and an increased number of active sites resulting from the nanopores created inside the g-C 3 N 4 sheets. Moreover, molecular dynamics (MD) simulations confirm that the interaction between AA and melamine molecules at elevated temperatures results in the formation of C-doped porous and exfoliated g-C 3 N 4 structures. Therefore, the present approach is very promising for application to the design of new and efficient photocatalysts for photocatalytic H 2 evolution under visible irradiation.
Original language | English |
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Pages (from-to) | 1004-1012 |
Number of pages | 9 |
Journal | Catalysis Science and Technology |
Volume | 9 |
Issue number | 4 |
DOIs | |
Publication status | Published - 2019 |
Externally published | Yes |