<p>The oxygen reduction reaction (ORR) with a 4e⁻ process is the key half-reaction for fuel cells and metal-air batteries, while the multielectron pathway leads to sluggish kinetics that hinder their development. Herein, hollow PtCo alloy materials with an icosahedral structure were synthesized through solvothermal and etching methods, which possess more active sites and a larger electrochemically active surface area. The obtained hollow PtCo alloy icosahedral nanocrystals exhibited superior kinetics toward the ORR than Ag@PtCo icosahedral nanocrystals, indicating that the void-confinement effects of the hollow structure improve the electron transfer. Meanwhile, the hollow PtCo alloy icosahedral nanocrystals achieve superior ORR performance, exhibiting an onset potential of 1.066 V vs. reversible hydrogen electrode (RHE), a half-wave potential of 0.967 V vs. RHE, and a Tafel slope of 61.27 mV dec⁻¹, which is owing to improved mass transfer from the hollow porous channels, high Pt atom utilization, and coupled with enhanced intrinsic activity from the strain effect that optimizes the d-band electronic structure. This work provides new insights into overcoming the challenges of future directions for Pt-based ORR electrocatalysts in fuel cells.</p>