An oxygen evolution catalyst on an antimony doped tin oxide nanowire structured support for proton exchange membrane liquid water electrolysis

Abstract

Developing catalysts with high electrocatalytic activity has recently attracted much attention due to the slow reaction kinetics for oxygen evolution reaction (OER) and poor durability under harsh operating environments. Aiming at the enhancement of oxygen electrode kinetics and durability, a facile and scalable electrospinning method is employed to fabricate antimony doped tin oxide nanowires (Sb–SnO₂ NWs) as support materials for iridium oxide. Both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results show that the as-prepared Sb–SnO₂ NW is stacked from primary Sb–SnO₂ nanoparticles (Sb–SnO₂ NPs) with diameters of 15–25 nm and exhibits a uniform porous nanowire structure with diameters in the range of 200–300 nm. The synthesized Sb–SnO₂ NW has a BET surface area of 60 m² g⁻¹ and an electronic conductivity of 0.83 S cm⁻¹. Benefiting from the porous nanowire structure and high electronic conductivity of the Sb–SnO₂ NW support, the supported IrO₂ catalyst exhibits significant enhancement of mass activity toward OER in acidic electrolytes compared with that of Sb–SnO₂ NP supported IrO₂ catalyst and pure IrO₂. The improved catalytic performance for OER is further confirmed by proton exchange membrane (PEM) electrolyzer tests at 80 °C. A test of such an electrolyzer cell at 450 mA cm⁻² shows good durability within a period of up to 646 h.