2D vanadium diselenide as a high performance catalyst

Abstract Electrocatalytic water splitting and photocatalytic water splitting have been widely researched in the progress of hydrogen generation. Among them, The former is of great significance to produce high-purity hydrogen industrially, while The latter is considered to be a efficient, low energy consumption and a green way of hydrogen production. Herein, we design a simple hydrothermal method to synthesize VSe2 with superior photocatalytic activity and HER/OER Electrochemical experiments reveal the samples with overpotential of 0.796 V in 0.5 M H2SO4 and 1.011 V in 1 M KOH for HER at current density of −10 mA cm−2, respectively. The VSe2 also exhibited optimal electrocatalytic properties for hydrogen evolution reaction (HER) with a low Tafel slope of 134.4 mV dec−1 (in 0.5 M H2SO4) and 242.44 mV dec−1 (in 1 M KOH), respectively. Furthermore, VSe2 has an extremely overpotential of 2.467 V at 10 mA cm−2 and Tafel slope of 247.43 mV dec−1 in 1 M KOH for OER. The electrochemical properties of VSe2 are mainly attributed to the high conductivity and the atomic composition way of each layer. Photoelectrochemical tests prove that the photocurrent density of VSe2 exhibits 107 μA/cm2 in 1 M KOH at 0.8 V. The superior photocatalytic activity is benefited from its intrinsic electronic structure.