Tuning Electronic Correlations of Ultra-small IrO2 Nanoparticles with La and Pt for Enhanced Oxygen Evolution Performance and Long-durable Stability in Acidic Media

•The ultra-small Pt, La co-doped IrO2 nanoparticles (2 nm) dispersed on NC was designed.•Pt0.1La0.1-IrO2@NC exhibited exhibited an overpotential of 205 mV (10 mA·cm−2) and stability of 135 h toward OER in 0.5 M H2SO4.•Pt0.1La0.1-IrO2@NC exhibited ahigh TOF (5.71 s−1, η =280 mV), outperforming the Ir-based catalysts reported up now.•DFT revealed doping of Pt, La into IrO2 could tune d band centers and lower ΔG forpotential-determining step toward OER.