Synthesis and characterization of novel high-performance composite electrocatalysts for the oxygen evolution in solid polymer electrolyte (SPE) water electrolysis

Novel Ru0.3Ir0.7O2/Pt0.15 composite electrocatalysts for the oxygen evolution in solid polymer electrolyte (SPE) water electrolysis were prepared by a two-step method. The intermediate Pt black with or without heat treatment (the final samples marked as C1 and C2 respectively) was firstly synthesized by a conventional reduction method with ultrasonic dispersion. The composite electrocatalysts were then prepared by impregnation-reduction method with ultrasonic dispersion followed by fusion treatment. The influence of heat treatment of intermediate Pt black on the properties of the composites was explored. The as-prepared composites were characterized by XRD, BET, SEM, EDX, CV and LP. The catalytic performance of the as-prepared electrocatalysts has also been investigated in a 20 cm2 SPE electrolytic cell using Nafion® 117 as an electrolyte with the loading of noble metals of 1.8 mg cm−2 at anode and 0.3 mg cm−2 at cathode. It shows that the catalytic performance of samples C1 and C2 is obviously higher than that of commercial PtIrO2 electrocatalyst and the catalytic activity of C1 electrocatalyst for the oxygen evolution is evidently higher than that of C2 electrocatalyst in the whole range of cell voltage. The cell voltage was only 1.76 V and 1.90 V when the current density is 1.0 A cm−2 and 1.5 A cm−2 respectively using sample C1 as anode electrocatalyst.