Porous MoP network structure as co-catalyst for H2 evolution over g-C3N4 nanosheets

Abstract

Exploring an efficient and inexpensive noble-metal-free co-catalyst to replace noble-metal is a huge challenge for photocatalytic H2 evolution. Transition metal phosphides (TMPs) as co-catalysts for photocatalytic H2 generation have been extensively employed due to their exceedingly good property, stability and low cost. Herein, a new photocatalyst containing g-C3N4 and porous network-like MoP as a highly efficient co-catalyst was fabricated. The maximal H2-generation rate of the MoP/g-C3N4 photocatalyst could reach 327.5 µmol·g−1·h−1, which was ∼3.4 times higher than that of pure g-C3N4. The quantum efficiency achieved 9.6% at 400 nm. The improvement in photocatalytic H2-generation of MoP/g-C3N4 was resulted from the proper Fermi level alignment and the close contact interfaces of porous network-like MoP and g-C3N4, in which MoP not only increased light absorption but also fasted the separation and transfer of photogenerated carriers as well as lowered the H2 evolution overpotentials. The possible photocatalytical mechanism of the MoP/g-C3N4 photocatalyst was speculated based on various characterization techniques. It is believed that this study can offer a novel pathway to design high-performance and low-cost photocatalytic materials composed of metal phosphide co-catalyst for efficient water-splitting H2-generation over semiconductors under visible-light illumination.