Pt/RuO₂-TiO₂Electrocatalysts Exhibit Excellent Hydrogen Evolution Activity in Alkaline Media

Abstract

Alkaline water electrolysis is hindered by the slow kinetics of the hydrogen evolution reaction (HER) in alkaline media. We report enhanced HER activity of Pt on a mixed-metal-oxide support composed of titanium dioxide (TiO2) and ruthenium dioxide (RuO2). The Pt/RuO2-TiO2 (Pt/RTO) electrocatalyst was characterized by XRD, TEM and BET. The particle size of Pt was 6 ± 0.63 nm and the support surface area was 33 ± 1.15 m2/g. The activity of Pt/RTO toward HER and the hydrogen oxidation reaction (HOR) in 0.1 M KOH was compared against a benchmark Pt/C catalyst (46.5%Pt; Tanaka, K. K.) using the rotating disk electrode (RDE) technique. Pt/RTO outperformed the benchmark Pt/C over the range of temperatures studied (275–313 K). The exchange current density for Pt/RTO was 2.31 ± 0.06 mA/cm2Pt (at 295 K, 1600 rpm, in H2-saturated 0.1 M KOH), which was more than five times the measured exchange current density of the Pt/C benchmark under the same conditions. Pt/RTO and Pt/C were further evaluated in a solid-state alkaline water electrolyzer operated with ultrapure water. MEAs fabricated with Pt/RTO as the cathode and IrO2 as anode catalyst showed a 100–200 mV reduction in the cell voltage across the entire current density range, when compared to MEAs fabricated with Pt/C at the cathode and IrO2 at the anode.