Dimensionality Engineering of 1D, 2D, and 3D High‐Entropy Alloys for Advanced Electrocatalysis

High‐entropy alloys (HEAs) are emerging as promising candidates for advanced electrocatalysis due to their multi‐elemental compositions, tunable electronic structures, and remarkable stability. Recent advances in synthesis have enabled the fabrication of HEAs with diverse dimensional architectures, including 1D, 2D, and 3D forms, each offering distinct advantages for active site exposure, electron and mass transport, and structural robustness. However, comprehensive reviews on the synthesis and electrocatalytic applications of HEAs across different dimensions remain scarce. This review systematically summarizes state‐of‐the‐art strategies for the controlled synthesis of dimensionally engineered HEAs, highlighting the unique features and advantages of 1D, 2D, and 3D forms. We further discuss their electrocatalytic performance in key energy conversion reactions, including water splitting, hydrogen oxidation reaction, oxygen reduction reaction, carbon dioxide reduction reaction, and alcohol oxidation reaction, with special attention to how morphology influences catalytic activities. Finally, we outline current challenges and future perspectives in the rational design, scalable synthesis, and development of multi‐dimensional HEA systems. This review provides a comprehensive understanding and perspective of dimensional engineering in HEA synthesis and electrocatalysis, aiming to inspire further exploration next‐generation catalyst development.