Synthesis, stability, and intrinsic photocatalytic properties of vanadium diselenide

As a typical, layered, so-called semimetal, vanadium diselenide (VSe2) is significantly different from other transition metal dichalcogenides (TMDs). With an overlap in its energy band between conduction band (CB) and valence band (VB), it can hardly have the potential for optoelectronic applications in theory. However, excellent intrinsic photocatalytic properties have been found in bulk 1T-VSe2 for the first time in this study. Typically, 28 mg L-1 of methyl orange (MO) was completely degraded within 30 min by 3 mmol L-1 of bulk VSe2. Based on the experimental results, a new photocatalytic mechanism different from that for semiconductors has been proposed. Moreover, the stability of VSe2 was studied and the results indicated that VSe2 can decompose by itself under extreme conditions. Fortunately, its self-decomposition can be prevented in the photocatalytic process, which is meaningful for practical applications.