A New Core/Shell NiAu/Au Nanoparticle Catalyst with Pt-like Activity for Hydrogen Evolution Reaction

Abstract

We report a general approach to NiAu alloy nanoparticles (NPs) by co-reduction of Ni(acac)2 (acac = acetylacetonate) and HAuCl4·3H2O at 220 °C in the presence of oleylamine and oleic acid. Subject to potential cycling between 0.6 and 1.0 V (vs reversible hydrogen electrode) in 0.5 M H2SO4, the NiAu NPs are transformed into core/shell NiAu/Au NPs that show much enhanced catalysis for hydrogen evolution reaction (HER) with Pt-like activity and much robust durability. The first-principles calculations suggest that the high activity arises from the formation of Au sites with low coordination numbers around the shell. Our synthesis is not limited to NiAu but can be extended to FeAu and CoAu as well, providing a general approach to MAu/Au NPs as a class of new catalyst superior to Pt for water splitting and hydrogen generation.

Activation Effect of Electrochemical Cycling on Gold Nanoparticles towards the Hydrogen Evolution Reaction in Sulfuric Acid

“…current densities calculated here are based on the real surface area of gold nanoparticles, which is derived from the reduction peak of gold. Similar to the report by Sun et al [39], when cycled in the double layer region, the onset potential of the HER shifts positively with the increased number of potential cycles; the results shown here are the steady value. A comparison of the overpotential, (h = E onset À E 0 , where E onset is the potential when HER occurs, Eo is the standard potential of the HER), of the HER needed for Au-NPs/GCEs cycled under different potentials is made in the insert in Fig.…”

“…The DG H* on the terrace Au(111) surface is calculated to be 0.45 eV following the work of Nørskov [16]. As shown, there are decreases of the DG H* on the stepped Au leading to a stronger bonding between hydrogen atom and the gold surface [39]. Gold is generally recognized to be a poor HER catalyst due to the weak adsorption of atomic hydrogen while a good HER catalyst should present a thermoneutral adsorption free energy, that is to say DG H* = 0 [55].…”

Overpotential for CO2 electroreduction lowered on strained penta-twinned Cu nanowires

“…This technique allows the study of electrochemical reactions without the explicit treatment of solvated protons, and has been widely used in the literature. 49–51 More computational details can be found in the ESI †. The free energy difference Δ G ( U ) between two adjacent intermediates is expressed as a linear function of the applied potential U vs. the reversible hydrogen electrode (RHE): 8,15 Δ G ( U ) = Δ G ( U = 0) + neU ,where n is the number of proton–electron pairs transferred to CO 2 and e is the positive elementary charge.…”

A simple electrochemical method for conversion of Pt wires to Pt concave icosahedra and nanocubes on carbon paper for electrocatalytic hydrogen evolution

“…First, Pt concave icosahedra and nanocubes present atomic steps and kinks with low coordination numbers, which have been proved to be beneficial for electrocatalysis such as hydrogen adsorption and evolution [45][46][47]. Second, small Pt nanoparticles on the commercial Pt/C catalyst are usually enclosed by (200) and dominant (111) facets (Fig.…”