Electrocatalytic Organic Dye Pollutants Degradation with Green Hydrogen Recovery using Nanoscale NiSe Catalysts

Abstract This work investigates the potential for simultaneous water pollutant treatment and green H 2 generation through the use of a highly active catalyst material in the water electrolysis process. We synthesised nanoscale Ni 2 Se 3 through a solvothermal method, analysing the crystallite structure through X-ray diffraction analysis. The electrochemical properties of as-synthesised Ni 2 Se 3 nanoscale catalysts were studied by using both a freshwater and dyewater electrolyte. Interestingly, the dyewater displayed an increased electrocatalytic activity as a result of the organic pollutants oxidising. We demonstrated the feasibility of benchmarking the Ni 2 Se 3 catalyst in methyl orange (model pollutant) dye pollutant degradation whilst simultaneously recovering hydrogen gas. The Ni 2 Se 3 -coated stainless steel anode resulted in 71.9% dye degradation over 180 min at 1.67 V vs RHE. Feasibility of hydrogen recovery during dye degradation process was examined. Interestingly, protons produced from dye degradation process at Ni 2 Se 3 anode, further reduced at cathode which generated approximately 0.81 L cm −2 of green hydrogen gas per day. This work explores an interesting investigation into the utilisation of a less expensive electrocatalyst to address the environmental clean-up and energy demand issues concurrently. Furthermore, it opens a circular economy pathway of recovering hydrogen gas from wastewater treatment. Graphical Abstract