MoO3/g-C3N4 Z-scheme (S-scheme) system derived from MoS2/melamine dual precursors for enhanced photocatalytic H2 evolution driven by visible light

Abstract

A dual-precursors co-pyrolysis strategy was adopted to prepare photocatalysts of MoO3/g-C3N4 composite from MoS2/melamine through a facile one-pot method. By following this strategy, MoS2 was in-situ transformed to MoO3 accompanying with the pyrolysis and polymerization of melamine to g-C3N4 nanosheets. A set of samples about MoO3/g-C3N4 composite containing different MoO3 contents were prepared and the visible-light driven photocatalytic performance of samples were investigated. The photocatalytic activity was notably enhanced and the highest evolution rate for H2 reached 13.9 times and 2.5 times that of the pristine g-C3N4 and the MoO3/g-C3N4 derived from MoO3/melamine, respectively. On the one hand, layered MoS2 used as the precursor of MoO3 contributed to the intimate contact with g-C3N4 nanosheets and the high dispersity of derived MoO3, and on the other hand, the morphology and electronic structure of g-C3N4 were actually changed by the strong interaction between the MoO3 and g-C3N4, thus inducing an efficient Z-scheme (S-scheme) system in the composite. The above-mentioned co-operation effect in the composite resulted in the significant improvement on the activity of photocatalytic H2 evolution. This work presented a valuable reference, by taking MoO3/g-C3N4 as an example, for the construction of composite-photocatalyst system in visible-light-driven H2 evolution.