CoCr₂O₄ Nanoparticles with Abundant Oxygen Vacancies: A New Photothermal Platform for Efficient Solar Evaporation

Abstract

Solar-driven interfacial photothermal evaporation has been recognized as a green, economical, and efficient water purification technique in recent years, and it is one of the most promising methods to realize the supply of high-quality freshwater resources. The key and challenge to achieving a superior water evaporation rate is to explore novel stable materials with high light absorption and photothermal conversion efficiency. In the present work, CoCr2O4 nanocrystals containing a large number of oxygen vacancies have been successfully prepared. Due to their substantial localized surface plasmon resonance effect and excellent photothermal performance, they are applied in the field of solar photothermal water evaporation for the first time. Thanks to their extremely high photothermal effect and excellent hydrophilicity, the outstanding water evaporation rate and efficiency of the obtained CoCr2O4 nanoparticles under standard sun irradiation are as high as 2.26 kg m–2 h–1 and 93.2%, respectively. This work provides an effective strategy for the development of new solar-driven interfacial evaporation materials.

MXene nanosheet-reinforced chitosan as a stable photothermal evaporator for efficient solar evaporation

“…The hydrophilic nature of the solar evaporator ensures an adequate water supply for the water vapor generation process, which is necessary for efficient solar evaporation. 39 Fig. 3H shows that the water droplets were absorbed by the CS/MXene aerogel within 1.3 s, facilitating water permeability.…”

Self-Floating Nanoporous High-Entropy Oxides with Tunable Bandgap for Efficient Solar Seawater Desalination

“…It is assumed that the multilevel porous structure can enhance the light absorption ability of the film due to the rich pore channels for strong light reflection and scattering. For typical semiconductors such as metal oxides, there are reports that Fe, Cr, Co and V can enhance the optical absorption of visible light. − Ti, Mo and Cu elements can enhance the optical absorption under ultraviolet light, − while Ni can enhance the absorption of near-infrared light . It is hypothesized that a similar effect also exists in our np-HEOs.…”

Enhancing Solar Steam Generation of Hydrogels via Silver Nanoparticle-Doped Cellulose Nanofibers

“…Recently, there has been a growing concern in cellulose nanofiber (CNF)-based hydrogels for SSGs due to their numerous advantages, including a high specific surface area, abundant sources in nature, hydrophilia, renewable, environmental friendliness, and biodegradability, which show vast application prospects in elastic hydrogels, ionic conduction, and biomedicine. − In addition, CNF-based hydrogels have been widely reported in the field of SSGs. − For example, Xu et al have reported a 3D photothermal aerogel composed of reduced graphene oxide (rGO), sodium alginate (SA), and cellulose fibers derived from rice straw, which has exhibited an evaporation rate of 2.25 kg m –2 h –1 with an energy conversion efficiency of 88.9% under one sun illumination. Han and coworkers presented Janus cellulose nanofibril-based aerogels consisting of MXenes, which showed an evaporation rate of 2.287 kg m –2 h –1 under one sun.…”