Bifunctional CuMoS4 for green energy production and storage

The growing need for energy and sustainability issues demand green energy production and storage. Research in this field needs better materials that can efficiently produce and store energy. Modified electrode materials with better electrochemical properties that can work as bifunctional materials to produce and store energy are much needed. In this work, copper-molybdenum sulfide synthesized using a self-assembled synthetic route was dip-coated onto nickel foam for energy generation (hydrogen via water splitting) and storage (supercapacitor). For water splitting applications, CuMoS4 displayed an overpotential of 207 mV to reach a current density of 10 mA/cm2 for hydrogen evolution reaction (HER). The Tafel slope associated with the HER activity of this material was 118 mV/dec. The overpotential needed to reach a current density of 10 mA/cm2 for oxygen evolution reaction (OER) was 270 mV. The OER activity of copper-molybdenum sulfide showed a Tafel slope of 82 mV/dec. Copper-molybdenum sulfide showed a specific capacitance of 3678 F/g at 2 A/g when tested for supercapacitors. The material showed great stability and experienced specific capacitance retention of 86.9% after 4,000 cycles. CuMoS4 produced results comparable to many other materials in literature and has promising results for applications for water splitting and supercapacitor