2D/2D Cs0.32WO3/CuS Nano‐Heterojunctions for Simultaneous High‐Efficiency Solar Desalination, Photocatalytic Decontamination, and Electricity Generation

Desalination and power generation through solar energy harvesting is a crucial technology that can effectively address freshwater shortages and energy crises. However, owing to the complexity of the actual water environment, the thermal output capability of the photothermal material and the functional integration of the evaporation system need urgent improvement, to obtain high-quality fresh water and sufficient electricity. Herein, a 2D/2D cesium tungsten bronze/copper sulfide (2D/2D Cs0.32 WO3 /CuS) nano-heterojunction is developed and it is loaded into a cellulose-based hybrid hydrogel to construct a multifunctional evaporator. Benefiting from the more nonradiative recombination centers from deep-level defects, as well as shorter carrier migration distances and higher redox potentials in the Cs0.32 WO3 /CuS nano-heterojunction, this evaporator has a significant improvement in thermal output capacity, enabling both super-efficient seawater evaporation (4.22 kg m-2 h-1 ) and photodegradation of organic pollutants (removal rate ≈ 99%). Moreover, the evaporator exhibits long-term stability and sustainable self-cleaning property against salt accumulation. Remarkably, the thermoelectric module based on the Cs0.32 WO3 /CuS nano-heterojunction shows promising electricity generation performance (4.85 W m-2 ), which can power small appliances durably and stably, exceeding previously reported similar devices. This 2D/2D heterojunction-based solar evaporation system will provide a more reliable solution for efficient and sustainable freshwater-electricity co-generation in resource-limited areas.