In Situ Synthesis of Mo<sub>2</sub>C Nanoparticles on Graphene Nanosheets for Enhanced Photocatalytic H<sub>2</sub>-Production Activity of TiO<sub>2</sub>
Jinfeng Liu, Ping Wang, Jiajie Fan, Huogen Yu, Jiaguo Yu
Abstract
Molybdenum carbide (Mo2C) has been proven to be the most promising candidate for the H2-evolution cocatalyst due to the similar H+-adsorption ability to Pt. However, owing to its limited electrical conductivity, the Mo2C-modified photocatalysts usually exhibit a low H2-evolution performance. Considering the perfect electron mobility of graphene nanosheets, in this article, Mo2C nanoparticles (ca. 5 nm) were in-situ and evenly grown on the reduced graphene oxide (rGO) to prepare the graphene-modified Mo2C (rGO-Mo2C) nanoparticles to improve the photocatalytic hydrogen-generation rate of TiO2. Herein, the rGO-Mo2C is obtained by the direct calcination of graphene oxide (GO) as the carbon source and (NH4)6Mo7O24 at 800 °C, which is further coupled with the TiO2 to synthesize the efficient TiO2/rGO-Mo2C photocatalyst. The greatest hydrogen-generation activity of TiO2/rGO-Mo2C achieved 880 μmol h–1 g–1 (AQE = 2.64%), which was 5.5 and 88 times higher than that of TiO2/rGO and TiO2, respectively. The boosted performance of TiO2/rGO-Mo2C can be attributed to the synergetic action that the rGO nanosheets can act as electron media to promote the photoelectron transfer, and the Mo2C nanoparticles can serve as active centers to improve the interfacial hydrogen-generation reaction. This work can provide a new synthesis strategy for the design of efficient cocatalysts for potential applications.