One-step calcination synthesis of WC–Mo2C heterojunction nanoparticles as novel H2-production cocatalysts for enhanced photocatalytic activity of TiO2†
Hexagonal molybdenum carbide (Mo2C) as a high-efficiency non-noble cocatalyst has been widely applied in the photocatalytic H2-generation area due to its platinum-like H+-adsorption potential, high thermal stability, and excellent electrochemistry properties. However, Mo2C possesses relatively low electrical conductivity and strong Mo–H bonds, resulting in a limited H2-generation activity of Mo2C-modified photocatalysts. In this paper, a tungsten carbide–molybdenum carbide (WC–Mo2C) heterojunction was constructed by introducing WC with high electrical conductivity into Mo2C for weakening the Mo–H bond. The carbon-coated WC–Mo2C heterojunction nanoparticles (WC–Mo2C@C) by one-step calcination of a controllable ratio mixture (melamine (MA), (NH4)6Mo7O24 and (NH4)6H2W12O40) at 800 °C were decorated on a TiO2 surface to form WC–Mo2C@C/TiO2 for the enhanced hydrogen-production performance of TiO2. The H2-production results showed that the highest H2-production rate of WC–Mo2C@C/TiO2 reached 903 μmol h−1 g−1 (AQE = 2.70%), which was 90.3, 3.6 and 2.5 times higher than that of TiO2, Mo2C@C/TiO2, and WC@C/TiO2, respectively. The enhanced performance of WC–Mo2C@C/TiO2 can be attributed to the addition of W element being able to simultaneously increase the conductivity of Mo2C and weaken the Mo–H bond for boosting the photocatalytic H2-production reaction of TiO2. This work provides a feasible strategy to explore efficient Mo2C-modified photocatalysts in the H2-generation field.