Cation-π interactions regulate electrocatalytic water oxidation over iridium single atoms supported on conjugated polymers

Designing cost-effective and high-performing metal catalysts is significant for many renewable energy conversion technologies. Lowering metal loading without sacrificing activity and durability is highly desired for the catalyst design, especially for those reactions where the noble metals deliver the best catalyzing performance. Single-atom catalysts (SACs) with maximal metal-atom utilization, homogeneous and tailorable active sites have emerged as promising catalyst candidates, where the local coordination structures of the metal atoms in SACs largely determine the reaction kinetics. Previous design strategies of constructing strong metal-support interactions can stabilize the individual metal atoms in SACs, but present obstacles to provide a flexible manipulation platform for elaborately tailoring the coordination structures to achieve performance optimization towards a specifically targeted reaction. Here, for the proof-of-concept study, we report a novel design of SAC with iridium (Ir) single atoms supported on conjugated polymer, in which the adsorption energies of reaction intermediates on Ir atoms and the reaction kinetics towards acidic water oxidation can be readily optimized through modulating the formed cation-π interactions that can be tailored by adjusting the molecular structures of conjugated polymers. This strategy establishes a general route to develop targeted SACs for various catalytic reactions.