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 (MoC@C) nanoparticle was synthesized and used as an effective cocatalyst to improve the H-2-evolution efficiency of TiO2. The cubic MoC@C can be obtained by adjusting the mass ratio of C3N3(NH2)(3) to (NH4)(6)Mo7O24 (2:1) and controlling the calcination temperature to 800 degrees C. When the above cubic MoC@C nanoparticles were evenly loaded on the TiO2 via a sonication-assisted deposition, a homogeneous composite of TiO2/MoC@C was formed due to the strong coupling interface between TiO2 and cubic MoC nanoparticles. More importantly, the highest H-2-production rate of TiO2/MoC@C reached 504 mu mol h -1 g(-1) (AQE= 1.43%), which was 50 times as high as that of the pure TiO2. The enhanced performance of TiO2/MoC@C can be attributed to the synergistic effect of carbon layer as an electron mediator and the cubic MoC as interfacial H-2-evolution active sites. This work provides a feasible guideline to develop high-efficiency Mo-based cocatalysts for potential applications in the H-2-evolution field. (c) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.