Rapid solar-driven seawater hydrogen production by wicking-heating-photoelectrocatalysis synergy via paper-based electrode

Utilizing thermoelectric generators (TEG) to boost photoelectrochemical water splitting (PEC) is an effective way to harness waste heat from the solar system and thus improve the solar-to-hydrogen conversion efficiency. However, conventional schemes rely on bulk water heating, which suffers from high thermal inertia, long response time, and significant heat dissipation. This study proposes a novel paper-based electrode (PBE) that leverages capillary action to transport a thin layer of water to the hot surface of the TEG. The PBE design couples the localized heating-photo electrocatalysis with interfacial electrolyte transport mechanism, enabling rapid thermal response while facilitating simultaneous hydrogen production and seawater desalination. Experimental results show that the TEG achieves the desired operating temperature condition as short as three minutes under 1000 W/m² solar illumination. The hydrogen production-seawater desalination system based on PBE and TEG exhibits a photovoltage of 1.88 V and a current density of 2.65 mA/cm², with a solar-to-hydrogen efficiency of 3.1%, a seawater desalination rate of 1.12 L/(m²·h) and a salt removal capacity of 37.4 g/(m²·h) under one-sun illumination. After benchmarking with commercial electrode, the proposed PBE offers a significant cost advantage, providing a scalable pathway for high-efficiency, photothermal-driven PEC systems. • A paper-based electrode with wetting properties and photo-catalytic functions. • A Wicking-Heating-Photoelectrocatalysis Synergy synergy based on paper-based electrodes was constructed. • Realize a full-spectrum solar-energy-driven photoelectric-photothermal synergistic system. • Utilizing capillary effect and waste heat to enhance the photocatalytic process. • forming an mechanism of hydrogen production–seawater desalination.