The exploration of alternative and clean energy sources and the reduction of environmental pollution are becoming ever more important for sustainable human progress. Electrochemical water splitting is appeared as vital technology for the achievement of energy conversion and storage targets based on hydrogen energy. Oxygen and hydrogen evolution reactions are taken into consideration as key half-reactions occurring at the anode and cathode, respectively, however the development of electrocatalytic water splitting are restricted because of their excessive overpotential values. In addition to, supported noble metal-based, especially Pt, electrocatalysts are the best electrocatalysts for these reactions, however restrained storage, high cost, and poor durability of these precious metals are the major challenges towards widespread applications of such clean energy technology. So, the search for new methods to reduce the amount of noble metals used in electrocatalysts via increasing its utilization efficiency or replace them with the other abundant and inexpensive materials for electrocatalysts has been a topic of current interest [1]. Transition-metal alloy has attracted a great deal of attention as an alternative to Pt-based catalysts for hydrogen evolution reaction [2]. Herein a highly efficient and durable reduced graphene oxide supported molybdenum-iridium (Mo-Ir/RGO) nanoalloy was reported for the first time as an electrocatalyst in hydrogen evolution reaction. The Mo-Ir/RGO nano alloy is obtained by a chemical co-reduction method by using IrCl3.3H2O and phosphomolybdic acid as iridium and molybdenum precursor. The fabricated nanocatalyst has been characterized by X-Ray Diffraction (XRD) and its electrocatalytic activity toward the hydrogen evolution reaction in 0.5 M H2SO4 solution has been evaluated by linear sweep voltammetry. The catalyst exhibits an excellent performance with a pretty low overpotential (-66 mV for delivering the current density of -10 mA cm-2). At the same time, the catalyst demonstrates excellent stability during the long-term measurements. As expected just 3 wt% Mo-Ir alloy loading of synthesized catalyst can match the commercial Pt/C (10 wt%).
