The synergy of thermal exfoliation and phosphorus doping in g-C3N4 for improved photocatalytic H2 generation

Photocatalytic H-2 generation has been believed to be a hopeful technology to deal with the current energy shortage issue. Among multifarious photocatalysts, graphitic carbon nitride (g-C3N4) has acquired enormous interests in virtue of its numerous advantages, such as peculiar physicochemical stability, favorable energy band structure and easy preparation. However, the insufficient light response range, low specific surface area, and inferior charge separation efficiency make its photocatalytic activity still unsatisfactory. In this work, the thermal exfoliation method was taken to prepare the thin g-C3N4 nanosheets with significantly improved specific surface area, which can afford more reaction sites and shorten the charge migration distance. Moreover, phosphorus (P) doping in g-C3N4 nanosheets can greatly expand its light absorption, improve the conductivity and charge-transfer capability. Due to the synergistic effect of these two strategies, the optimal H-2 generation performance of P-doped g-C3N4 nanosheets came up to 1146.8 mu mol which improved 15, 2.94 and 2.62 times compared to those of original bulk g-C3N4, thermally exfoliated g-C3N4 and P-doped bulk g-C3N4, respectively. The synergistic effect will inspire the design of other photocatalytic systems to achieve the efficient photocatalytic H-2 generation activity. (C) 2020 Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.