Improving electrocatalytic activity of iridium for hydrogen evolution at high current densities above 1000 mA cm−2

The exploration of electrocatalysts with high activity and durability for hydrogen evolution reaction (HER) at extremely high current densities above 500 mA cm−2 in alkaline media is the basis for large-scale industrial applications. Plain Ir possesses optimum performance for OER in alkaline electrolytes but presents a noticeable underperforming HER activity. Herein, the strategy by pyrolyzing Ir-modified metal-organic frameworks (MOFs) precursors has been employed in designing electrocatalysts consisting of IrFe nanoalloys supported on N-doped carbon layers. The catalyst requires a small overpotential of 105 mV to deliver a current density of 100 mA cm-2 in basic media, which surpasses that of commercial Ir/C and Pt/C benchmarks. Particularly, the catalyst also exhibits an extraordinary performance with low overpotential of only 850 mV at 1000 mA cm-2. The extraordinary performance originates from superior conductivity, the modulated electronic structure and large specific surface area.