Fig. 3: Electrocatalytic HOR performances.
From: Ternary nickel–tungsten–copper alloy rivals platinum for catalyzing alkaline hydrogen oxidation
a Polarization curves for the HOR on Ni5.2WCu2.2, Ni17W3, Ni, and commercial Pt/C catalyst measured in H2-saturated 0.1 M KOH. Scan rate: 1 mV s−1. Inset shows HOR curves at high anode potentials, showing the surface oxidation of Ni17W3 and Ni catalysts. b Comparison of breakdown potential of Ni5.2WCu2.2 with various PGM-free HOR catalysts reported previously. Breakdown potential means HOR stops at this potential. c Comparison of exchange current density (j0) of various studied catalysts normalized by geometric areas (unpatterned) and ECSA (patterned), respectively. d HOR/HER Tafel plots of the kinetic current density on Ni5.2WCu2.2, Ni17W3, Ni, and Pt/C in H2-saturated 0.1M KOH. e HOR polarization curves for Ni5.2WCu2.2 alloy and Pt/C catalyst in H2-saturated 0.1M KOH with (dashed lines) and without (solid lines) the presence of 20,000 ppm CO. f HOR polarization curves for Ni5.2WCu2.2 alloy and Pt/C catalyst before (solid lines) and after (dashed lines) accelerated durability test, respectively. The durability test was performed at room temperature in H2-saturated 0.1M KOH with the cyclic potential sweeping between −0.2 V to 0.2 V at a sweep rate of 200 mV s−1. g Chronoamperometry (j - t) responses recorded on Ni5.2WCu2.2 alloy and Pt/C catalyst at a 300 mV overpotential in H2-saturated 0.1 M KOH at room temperature. Identical measurement on Ni5.2WCu2.2 alloy in Ar-saturated 0.1M KOH was also carried out for comparison.
