Development of IrO2-WO3 Composite Catalysts from Waste WC-Co Wire Drawing Die for PEM Water Electrolyzers' Oxygen Evolution Reactions

Recycling waste materials as catalysts in the oxygen evolution reaction (OER) offers an innovative approach to reducing catalyst costs. Scrap tungsten carbide-cobalt (WC-Co) die, used in wire drawing processes in industrial applications, may be recovered as tungsten trioxide (WO3) by the electrolysis method. In this study, all composite catalysts were prepared as their weight percentage IW-x (0 <= x <= 100). Here, I, W, and x represent IrO2, WO3, and the weight percent of Ir in the mixed composite oxide, respectively. Then, the prepared IW-75, IW-50, and IrO2 catalysts are referred to as 75% IrO2-25% WO3, 50% IrO2-50% WO3, and Ir's pure oxide form, respectively. These materials are compared with WO3 and IrO2 to investigate their OER performance. According to the linear sweep voltammetry results, the IW-75 catalyst has a 15.03% higher current density than the pure IrO2 catalyst. In the Tafel polarization curve of the catalysts, it is determined that the corrosion potential of IW-75 is enhanced, and the overpotential value is decreased 1.2 times compared to the synthesized IrO2 catalyst sample. As a result, using composite oxide from scrap wire drawing die and IrO2, the cost of the proton-exchange membrane water electrolyzer's anode catalyst is reduced by more than 25%.