Engineering Molybdenum Diselenide and Its Reduced Graphene Oxide Hybrids for Efficient Electrocatalytic Hydrogen Evolution

Abstract

We report the hydrogen evolution reaction (HER) with molybdenum diselenide (MoSe2) and its reduced graphene oxide (rGO) hybrids synthesized by a microwave process followed by annealing at 400 °C. The content of GO was varied to understand its role in the electrocatalytic activities. Electrochemical performance of the as-synthesized and the annealed catalysts underscores (i) a requirement of catalytic activation of the as-synthesized samples, (ii) an apparent shift in the onset potential as a result of annealing, and (iii) striking changes in the Tafel slope as well as the overpotential. The results clearly reveal that partially crystalline plain MoSe2 is more elctroactive in comparison to its annealed counterpart, whereas annealing is advantageous to MoSe2/rGO. Improved HER performances of the annealed MoSe2/rGO hydrids arise from the synergistic effect between active MoSe2 and rGO of improved conductivity. The annealed hybrid of MoSe2 with rGO designated as MoSe2/rGO100_400 °C demonstrated an excellent HER activity with a small onset potential of −46 mV vs reversible hydrogen electrode, a smaller Tafel slope (61 mV/dec), and a reduced overpotential of 186 mV at −10 mA/cm2. As a result of a convenient synthetic process and the suitable electrocatalytic performance, this study would be beneficial to designing and fabricating other nanomaterials with/without a conductive support for their versatile applications.