Carbon-coated cubic-phase molybdenum carbide nanoparticle for enhanced photocatalytic H2-evolution performance of TiO2

Conventional hexagonal dimolybdenum carbide (Mo2C) as a good cocatalyst has been widely applied for the enhanced photocatalytic hydrogen production of various photocatalysts. Compared with the hexagonal Mo2C, however, the investigation about cubic molybdenum carbide (MoC) is still very limited in photocatalytic field. In this study, carbon-coated cubic molybdenum carbide ([email protected]) nanoparticle was synthesized and used as an effective cocatalyst to improve the H2-evolution efficiency of TiO2. The cubic [email protected] can be obtained by adjusting the mass ratio of C3N3(NH2)3 to (NH4)6Mo7O24 (2:1) and controlling the calcination temperature to 800 °C. When the above cubic [email protected] nanoparticles were evenly loaded on the TiO2 via a sonication-assisted deposition, a homogeneous composite of TiO2/[email protected] was formed due to the strong coupling interface between TiO2 and cubic MoC nanoparticles. More importantly, the highest H2-production rate of TiO2/[email protected] reached 504 μmol h−1 g−1 (AQE=1.43%), which was 50 times as high as that of the pure TiO2. The enhanced performance of TiO2/[email protected] can be attributed to the synergistic effect of carbon layer as an electron mediator and the cubic MoC as interfacial H2-evolution active sites. This work provides a feasible guideline to develop high-efficiency Mo-based cocatalysts for potential applications in the H2-evolution field.