Carbon-Supported Platinum-Grafted Gold–Nickel Nanoclusters for Hydrogen Evolution Reaction

A carbon-supported platinum-grafted thiolate-protected precision AuNi nanocluster (NC) (Pt-AuNi/C) is studied for the hydrogen evolution reaction (HER) in acidic solution. The AuNi/C is doped with platinum through an electroless process. The HER performance is evaluated for AuNi/C and Pt-AuNi/C in a 0.1 M sulfuric acid solution. Typical HER behavior is noticed with the noticeable reduction in overpotential by ca. 208 mV RHE @ 10 mA cm –2 after platinum incorporation in the NCs. The HER curve on pristine NCs exhibits a contrasting steady-state limiting behavior, signaling a possible radial diffusion over the NCs. This result is expected for a random array-like arrangement of NCs, and this is witnessed as a changeover in steady-state limiting behavior to mass-transport free characteristics with increased proton concentration. However, the steady-state limiting behavior is obscured by the carbon support. Further, the Pt-AuNi/C is tested in a zero-gap cell, where cathodic current density of 2.3 A cm –2 was measured at the overpotential of 0.5 V RHE, which is much better than that of the benchmark Pt/C.