K⁺-Intercalation Engineering of 1D Ultrathin K_0.25IrO₂ Electrocatalyst for Industry-Level Proton Exchange Membrane...

Both commercial and lab-synthesized IrO₂ nanocrystals are crucial for acidic oxygen evolution reaction, which remain severely limited in practical proton exchange membrane water electrolysis (PEMWE) by the high overpotential and low stability. Here, we successfully construct 1D K_0.25IrO₂ nanocrystal via K⁺ Intercalation. Novel crystal structure will bring about novel catalytic property. Compared to traditional rutile-type IrO₂, DFT calculations reveal that the lattice regulation via K⁺ Intercalation lowers the energy barrier for OER and further optimizes the adsorption energy of oxygen intermediates. Therefore, 1D K_0.25IrO₂ presents an ultralow overpotential of 237 mV at 10 mA cm_geo ^-2 in a three-electrode cell, and performs excellent PEM activity with a low E_cell of 1.70 V at 2 A cm_geo ^-2. More importantly, the practical operating stability of the 1D K_0.25IrO₂ anode cell has been demonstrated under both industry-level constant and dynamic operating conditions. This work develops a novel K⁺-intercalation engineering for the precise synthesis of 1D ultrathin K_0.25IrO₂ electrocatalyst, exhibiting outstanding OER activity and stability in PEMWEs from steady-state to fluctuating power inputs.