Synergistic Effects of Light and Magnetic Fields in Electrocatalytic Water Splitting: From Fundamentals to Applications

Electrocatalytic water splitting is a promising pathway for sustainable hydrogen production; however, its efficiency remains constrained by sluggish reaction kinetics and high overpotentials. Recently, the integration of multiple external physical fields has emerged as a powerful strategy to enhance catalytic activity by tuning charge transfer, adsorption behavior, and reaction energetics. This review comprehensively summarizes the synergistic effects of light and magnetic fields in electrocatalytic water splitting, covering both fundamental mechanisms and recent advances. The light field promotes charge separation, local photothermal heating, and plasmon‐induced hot‐carrier generation, thereby accelerating the hydrogen and oxygen evolution reactions. Meanwhile, the magnetic field modulates spin polarization, induces magnetohydrodynamic convection, and triggers magnetothermal effects to facilitate mass transport and optimize reaction pathways. We further highlight dual‐field coupling strategies, in which light and magnetic fields collaboratively reconfigure the electronic structure, regulate intermediate adsorption states, and jointly lower reaction barriers, leading to nonlinear catalytic enhancement. Finally, current challenges and future opportunities are discussed, emphasizing the integration of photonic, magnetic, and electronic effects in the rational design of next‐generation electrocatalytic systems for efficient and low‐carbon hydrogen production.