BiVO4 nanocoral superstructures and their excellent electrical/optical dual-functions

Abstract

BiVO4 semiconductor materials have become a research hotspot in the optical/electrical field due to their unique narrow band gap and high conductivity, but it is still difficult to obtain assembled structures with dual high-performance optical/electrical functions. A novel monoclinic BiVO4 nanocoral-assembled superstructure with a narrow band gap and high conductivity was successfully synthesized for the first time at a low temperature by a green synthesis method (solid-hydrothermal method) created by our group. The unique superstructure is assembled by high-aspect-ratio nanorods, which not only exposes highly active surface, but also links the whole nanorods into a highly conductive network, thereby promoting the high utilization of components in this superstructure. Moreover, the generated hierarchical pores exhibit high absorption of light through multiple reflections. As a result, the synthesized material simultaneously possesses excellent electrochemical and photocatalytic properties. When used as a negative electrode in supercapacitor, this novel material delivered an ultrahigh specific capacitance of 788 F/g at a current density of 3 A/g, reaching 97% of its theoretical value and surpassing all reported values of BiVO4 based electrode materials. Importantly, this material shows a high rate capability and good cycling stability. When this BiVO4 superstructure is applied for photocatalysis, the reaction kinetics can be described by a first-order reaction rate constant that reaches 0.0264 min−1 for the visible-light catalysis removal of methyl blue. Additionally, the catalyst can completely degrade methyl blue in 150 min, which is difficult to achieve for most single visible-light catalysts. Thus, the above process is highly suitable for the efficient utilization of solar energy. This novel BiVO4 nanocoral superstructure with dual optical/electrical functions has broad application prospects in the energy, environmental and electronics fields.