Multiscale Design of Porous Architectures for Highly Efficient Oxygen Electrocatalysis

Driven by the global imperative for carbon neutrality and sustainable energy development, oxygen electrocatalysis, especially the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), has emerged as a key link between renewable electricity and clean energy conversion devices. However, the sluggish kinetics of these reactions severely limit energy efficiency, a challenge exacerbated by insufficient active-site utilization and restricted tri-phase mass transport. This review highlights recent advances in multiscale porous architectures for oxygen electrocatalysis, with particular emphasis on how pore size, connectivity, and hierarchical organization govern active-site accessibility, mass transport, and catalytic kinetics. Unlike previous reviews primarily centered on specific material categories, this work adopts a structure-function perspective to establish the correlations between porous architectures and electrocatalytic performance. Particular attention is given to d-band electronic-structure modulation and the confinement effects within hierarchically interconnected networks that expedite reactant diffusion. Finally, current challenges associated with structural stability under operating conditions, scalable fabrication, and operando mechanistic characterization are critically evaluated, and future perspectives for next-generation high-performance electrochemical devices are proposed to guide rational catalyst design.