Harnessing Synchronous Photothermal and Photocatalytic Effects of Substoichiometric MoO<sub>3–<i>x</i></sub> Nanoparticle-Decorated Membranes for Clean Water Generation
Jiaxin Ren, Zhipeng Liu, Qiang Li, Ling Chen, Jiang Gong, Huina Wang, Yiwen Li, Jinping Qu, Ran Niu
Abstract
Solar-driven interfacial evaporation provides a promising pathway for sustainable freshwater and energy generation. However, developing highly efficient photothermal and photocatalytic nanomaterials is challenging. Herein, substoichiometric molybdenum oxide (MoO 3– x ) nanoparticles are synthesized via step-by-step reduction treatment of l -cysteine under mild conditions for simultaneous photothermal conversion and photocatalytic reactions. The MoO 3– x nanoparticles of low reduction degree are decorated on hydrophilic cotton cloth to prepare a MCML evaporator toward rapid water production, pollutant degradation, as well as electricity generation. The obtained MCML evaporator has a strong local light-to-heat effect, which can be attributed to excellent photothermal conversion via the local surface plasmon resonance effect in MoO 3– x nanoparticles and the low heat loss of the evaporator. Meanwhile, the rich surface area of MoO 3– x nanoparticles and the localized photothermal effect together effectively accelerate the photocatalytic degradation reaction of the antibiotic tetracycline. With the benefit of these advantages, the MCML evaporator attains a superior evaporation rate of 4.14 kg m –2 h –1, admirable conversion efficiency of 90.7%, and adequate degradation efficiency of 96.2% under 1 sun irradiation. Furthermore, after being rationally assembled with a thermoelectric module, the hybrid device can be employed to generate 1.0 W m –2 of electric power density. This work presents an effective complementary strategy for freshwater production and sewage treatment as well as electricity generation in remote and off-grid regions.