Leveraging metal alloy-hybrid support interaction to enhance oxygen evolution kinetics and stability in proton exchange membrane water electrolyzers

Abstract

This study presents the unprecedented high OER performance of binary iridium (Ir) and ruthenium (Ru) nanoparticles on TiO2-oxide-decorated reduced graphene oxide (rGO) in acidic media. IrRu alloy electrocatalysts supported on TiO2-rGO (denoted as IrRu/TG) were prepared via ultrasonic spray pyrolysis, followed by the polyol method. TiO2-rGO (TG) support is used not only to disperse IrRu nanoparticles effectively but also to induce the electronic modulation of Ir by downshifting its d-band center compared to unsupported catalysts. IrRu/TG exhibits optimal OER performances and high stability when the weight ratio of TiO2:rGO is 90:10 (i.e., T90G10). The successfully synthesized IrRu/T90G10 exhibits remarkable OER activity, requiring a low overpotential of 254 mV to reach 10 mA cm-2 compare with the unsupported IrRuOx (372 mV), IrRu/rGO (325 mV), and commercial Ir black (340 mV). Moreover, TiO2-rGO (TG) support inhibits the aggregation and oxidative dissolution of IrRu species, thereby enhancing the stability in acidic media. In proton exchange membrane water electrolyzer (PEMWE) tests using membrane electrode assemblies (MEAs), IrRu/T90G10 shows more than twice the mass activity of commercial IrO2.