Ultralow-content Pt nanodots/Ni₃Fe nanoparticles: interlayer nanoconfinement synthesis and overall water splitting

This is the authors' abstract. We don't add key points for this paper.

Minimizing precious metal loading into electrocatalysts for water splitting is vital to promoting hydrogen energy technology toward practical applications. Low-content loading of precious-metal electrocatalysts is achieved by decorating precious metal nanostructures on co-electrocatalysts typically via surface confinement. Here, an electrocatalyst of ultralow-content Pt nanodots (0.71 wt%)/Ni₃Fe nanoparticles on reduced oxidation graphene (Pt/Ni₃Fe/rGO) is constructed for overall water splitting by pyrolyzing a single-source precursor PtCl₆³⁻ guest-intercalated MgNiFe-layered double hydroxide (MgNiFe-LDH) host via a distinctive interlayer confinement. Consequently, Pt/Ni₃Fe/rGO demonstrates attractive overpotentials of 240 and 76 mV at 10 mA cm⁻² for the oxygen and hydrogen evolution reactions (OER and HER), respectively, outperforming those of its /Ni₃Fe/rGO counterpart. Moreover, the Pt/Ni₃Fe/rGO∥Pt/Ni₃Fe/rGO electrolyzer generates a current density of 10 mA cm⁻² at 1.55 V, with a retention of 92.4% after 50 h. Furthermore, the measured specific activity and low transfer resistance, as well as the density functional theory (DFT) calculations, indicate that the active Pt/Ni₃Fe in Pt/Ni₃Fe/rGO can optimize the adsorption/desorption of reaction intermediates and thus boost OER/HER kinetics, all of which lead to enhanced performance. The results demonstrate that such an interlayer confinement-based synthesis strategy can allow for the design of cost-effective precious nanodots as potential electrocatalysts.