Enhanced active edge sites on MoSe2 nanostructures for stable electrocatalytic and photocatalytic hydrogen evolution reaction

In this work, we report a simple one-pot hydrothermal synthesis of MoX 2 and NiX 2 (X = O, S, and Se) for facilitating the catalytic hydrogen evolution reaction (HER) in acidic medium. The prepared metal chalcogenides were explored as both electrocatalyst and photocatalyst due to their excellent optical and electrical properties. Among the chalcogenides, MoSe 2 shows significantly enhanced electrocatalytic as well as photocatalytic activity. It is because the existence of porous surface enables abundant active sites for the evolution of hydrogen (H 2 ) gas. As a result, MoSe 2 -loaded electrode shows a low overpotential ( η ) of 216 mV vs RHE at 5 mA cm −2 with the Tafel slope of 105 mV dec −1 and high durability for about 1000 cycles. Further, the photocatalytic H 2 production measurements were carried out for all the prepared metal chalcogenides under the visible light irradiation. The optical band gap is calculated as 1.13 eV for MoSe 2 which is responsible for the superior photocatalytic performance with the H 2 production of 2676 μmol h −1 g −1 . Interestingly, MoSe 2 retains 96% of its photocatalytic activity even after 12 h of irradiation. The impact of morphology and the detailed study of band gap position have been correlated to the rate of the H 2 evolution. Graphical abstract