Confinement Effects in High‑Efficiency Electrocatalysis: Design, Mechanisms, and Applications

ABSTRACT The continued dominance of fossil energy has led to severe environmental pollution and resource depletion, underscoring the urgent need for sustainable energy conversion technologies to achieve carbon neutrality. Electrocatalysis has emerged as a promising solution, and confinement engineering has proven to be an effective strategy for enhancing electrocatalytic performance by precisely regulating the structure of active species, tailoring reaction microenvironments, and accelerating mass and charge‐transfer kinetics. Despite these advantages, the rational design of confined electrocatalytic systems remains challenging due to ambiguous structure–activity relationships, limited mechanistic understanding of confined reaction processes, and the difficulty of precisely controlling confinement effects in complex architectures. This review summarizes recent advances in the synthesis strategies, functional mechanisms, and structure–property relationships of confinement‑engineered electrocatalysts, with a particular emphasis on the role of zero‑ to three‑dimensional confined spaces in modulating electronic structures, promoting reactant adsorption, and lowering reaction energy barriers. Finally, critical challenges and future opportunities in confined electrocatalysis are discussed, including precise synthetic control, mechanistic elucidation, and practical implementation. This review aims to provide in‑depth insights to guide the rational design of high‑efficiency electrocatalysts and accelerate their translation into practical energy applications.