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

This work investigates the potential for simultaneous water pollutant treatment and green H₂ generation through the use of a highly active catalyst material in the water electrolysis process. We synthesised nanoscale Ni₂Se₃ through a solvothermal method, analysing the crystallite structure through X-ray diffraction analysis. The electrochemical properties of as-synthesised Ni₂Se₃ 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 Ni₂Se₃ catalyst in methyl orange (model pollutant) dye pollutant degradation whilst simultaneously recovering hydrogen gas. The Ni₂Se₃-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 Ni₂Se₃ 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: