Synthesis of h-MoO3 nanorods and h-/α-MoO3 composites and their photocatalytic performance
(1. State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China;
2. Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, China)
2. Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, China)
Abstract: A facile hydrothermal route for the synthesis of h-MoO3 nanorods and h-/α-MoO3 composites was proposed. XRD, TG-DSC, FESEM-EDX, TEM, FT-IR, Raman, photoluminescence (PL) and UV-vis DRS spectroscopy were used to characterize the as-synthesized products. h-MoO3 was formed when the liquid/solid ratio of the raw materials was 2:1 and 5:1. However, homogeneous h-/α-MoO3 composites were obtained when the liquid/solid ratio was increased to 8:1 and 12:1. A possible mechanism by which h-MoO3 is formed, and its transformation into α-MoO3 were investigated. h-MoO3 annealing was found to comprise three mass-loss stages; i.e., the removal of each of the following: physically adsorbed water, residual ammonium, and coordinated water. Both h-MoO3 nanorods and h-/α-MoO3 composites demonstrated excellent visible-light-driven photocatalytic performance with regard to methylene blue degradation. The superior degradation efficiency of the h-/α-MoO3 composites was ascribed to a lower recombination rate of electron-hole pairs, a reduced band gap energy, and an enhanced synergistic effect.
Key words: h-MoO3; α-MoO3; hydrothermal synthesis; photocatalytic performance; methylene blue