Photothermally Enhanced Electrocatalytic Water Splitting for Hydrogen Production

Hydrogen energy is a promising solution to global energy and environmental challenges. Water electrolysis is a green technology for hydrogen production, but its efficiency is limited by the electrocatalytic performance of the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Elevating the temperature of the electrolysis system is effective in accelerating the electrocatalytic efficiency. However, conventional heating methods often increase the system complexity and energy consumption. The photothermal effect, where a substance generates heat upon light absorption, enables localized heating, improves energy utilization, and offers a promising strategy to enhance electrolyzer performance. Here, recent advances in photothermally enhanced electrocatalytic water splitting for hydrogen production are comprehensively reviewed. We elucidate the mechanisms of electrocatalytic water splitting and photothermal effects, with particular emphasis on the multiscale mechanisms of photoenhanced electrocatalysis that integrate nanoscale localized heating, hot-carrier generation, interfacial restructuring, and system-level modulation to collectively accelerate the HER and OER. We have systematically introduced recent advances in the design of photothermally enhanced electrocatalysts, specifically in the HER, OER, and various anode alternative reactions. This review also introduces representative designs of photothermally enhanced electrolyzers. By conducting a comparative economic analysis of various electrolyzers, this review demonstrates the significant economic benefits of photothermally enhanced water electrolysis for hydrogen production. We also provide a perspective on the future research direction of photothermally enhanced electrocatalytic hydrogen production. This review will inspire future endeavors toward realizing highly efficient, energy-saving, and cost-effective hydrogen production systems.