Graphitic carbon nitride nanosheet for photocatalytic hydrogen production: The impact of morphology and element composition

The intrinsic morphology and basal plane defects on g-C 3 N 4 nanosheet have important influences on its electronic structures and photocatalytic activity. In this work, we report extending thermal treatment time of g-C 3 N 4 at 550 °C not only change the morphology of g-C 3 N 4 but also element composition of g-C 3 N 4 . The morphology variation results in largely increased SSA from 40.22 to 117.27 m 2 g −1 , obviously reduced pore size from 3.99 to 2.77 nm for g-C 3 N 4 and formation of in-plane holes. Moreover, composition variation of g-C 3 N 4 has also been found to have changed as the pyrolysis time extended. These changes have significant impact on the optical properties and photoelectrical characters of g-C 3 N 4 , which were investigated by UV-DSR, PL and Photocurrent measurement. The photocatalytic activity of g-C 3 N 4 obtained via 9 h thermal treatment at 550 °C has shown highest photocatalytic activity, which is 1.77 times than that of g-C 3 N 4 obtained via 3 h thermal treatment under visible irradiation and 1.99 times under UV irradiation respectively.