Unravelling the Role of Strong Metal-Support Interactions in Boosting the Activity toward Hydrogen Evolution Reaction on Ir Nanoparticle/N-Doped Carbon Nanosheet Catalysts.

Pt-based catalysts are commercial electrocatalysts for the hydrogen evolution reaction (HER), but their shortcomings of expensive and imperfect efficiency hinder their large-scale application. Here, we report an Ir-based HER catalyst supported by N-doped carbon nanosheets (Ir-NCNSs). The NCNSs, with a high surface area and unique atomic composition, enable Ir nanoparticles (NPs) to disperse at 2-3 nm and strongly coordinate to the Ir through Ir-N bonds, which exposes many active sites and strengthens their durability. The catalyst displays a low overpotential and a small Tafel slope of 46.3 mV at 10 mA cm-2 and 52 mV dec-1 in 0.5 M H2SO4, respectively. When used in 1.0 M KOH, Ir-NCNSs also show excellent electrocatalytic activity with a low overpotential of 125 mV at 10 mA cm-2. The calculated results further suggest that Ir NPs and NCNSs have excellent selectivity for strong metal-support interactions, corresponding to a significant and stable HER characteristic. Our findings provide insight into the design of high-efficiency Ir-based HER catalysts.