Hollow RuSe ₂ ‐MoSe ₂ @NC Microsphere/Chitosan Aerogel Janus Electrode for Solar‐Driven Photothermal‐Promoted Synchronous Seawater Splitting and Evaporation

ABSTRACT Driving seawater electrolysis for hydrogen production and solar‐driven seawater evaporation using appropriate materials are important approaches to address energy and freshwater shortages, respectively. Although high‐efficiency seawater electrolysis catalysts and solar evaporators have attracted extensive attention, no effective strategy has been developed to combine these two components. The prepared hollow flower‐like NC‐encapsulated RuSe ₂ ‐MoSe ₂ and carbon black (CB) are embedded into porous chitosan (CS) aerogel through a catalyst‐gel composite integration strategy. The synthesized RuSe ₂ ‐MoSe ₂ @NC/CB/CS exhibits superior catalytic performance, efficient photothermal conversion, and strong water absorption capacity. Moreover, the elaborately constructed asymmetric Janus structure is endowed with effective salt resistance. In alkaline seawater, RuSe ₂ ‐MoSe ₂ @NC/CB/CS exhibits outstanding hydrogen and oxygen evolution reaction performance, requiring only 1.81 V to drive overall water splitting (OWS) at 100 mA cm ⁻² , which further decreases to 1.77 V under 1 kW m ⁻² illumination. As a solar evaporator, it attains an evaporation rate of 2.80 kg m ⁻² h ⁻¹ with 92% photothermal efficiency. In this work, the solar‐driven photothermal effect is utilized to innovatively achieve synchronous seawater splitting and evaporation on a single electrode. Additionally, a coupled photothermal device designed for synergistic seawater electrolysis and evaporation is successfully operated under natural sunlight.