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

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