Surface charge modulation boosts electrocatalytic water splitting over iridium catalysts on a polyimide support.

Developing high-performance iridium (Ir)-based catalysts with minimal precious Ir metal is a significant but challenging step towards the acidic oxygen evolution reaction (OER). Here, we report a high-performance OER catalyst with Ir nanoparticles on a polyimide support, where the polyimide support can effectively modulate the electronic structures of the Ir active sites for decreased thermodynamic barriers, but also enrich the local proton concentration near the Ir active sites, enhancing the OER rates.