| Nickel selenide,as an important transition metal-sulphide compound material,has an important potential value in the field of photothermal conversion due to its intrinsic absorption,which is strong in the near-infrared and visible light regions.In this paper,nickel selenide(Ni0.85Se)nanomaterials were prepared and two composites,nickel selenide/graphite-like phase carbon nitride(Ni0.85Se/g-C3N4)and nickel selenide/carbon(Ni0.85Se/C),were prepared by in situ growth of the composite,and characterised by SEM,EDX,XRD,TEM and XPS under different synthesis conditions The effects of Ni0.85Se and its composites on the photothermal properties such as photothermal conversion efficiency and photothermal stability were investigated by means of photothermal warming tests and photothermal water evaporation tests,and the potential of the materials in the field of desalination was evaluated.(1)Nickel selenide materials were firstly synthesized by a simple two-phase solvothermal method,and Ni0.85Se materials were prepared by adjusting different synthetic reaction parameters to explore the optimal synthesis conditions of nickel selenide.In addition,g-C3N4 layered nanomaterials with a thickness of about 350 nm were prepared by a high-temperature calcination method,and it was also found that different plasmas had less influence on the photothermal properties of the modified carbon materials.(2)Based on the synthesis of Ni0.85Se,Ni0.85Se/g-C3N4 nanocomposites were prepared by introducing a graphite-like phase carbon nitride material composite,and it was characterized that the Ni0.85Se nanoparticles were uniformly distributed and in situ grown on the g-C3N4 lamellae,while the UV-vis spectra showed that the composites exhibited full spectral range absorption and strong effects.(3)After the Ni0.85Se/g-C3N4 composite was used to construct an interfacial photothermal water evaporation membrane device and tested,the water evaporation rate of the composite membrane device reached up to 1.272 kg·m-2·h-1 under one solar illumination,and the photothermal conversion efficiency was as high as 75.36%,and it was still at a good level after 14days of stability test,indicating that the Ni0.85Se/g-C3N4 composite has good photothermal stability.Meanwhile,the evaporation rate of water tested under simulated seawater conditions is little affected by water quality.(4)The Ni0.85Se/C series composites were synthesized based on the preparation of Ni0.85Se.The core-shell Ni0.85Se/C composites with a particle size of about 30?60 nm and an outer layer of thin carbon were synthesized at a reaction temperature of 200°C,a two-phase solvent ratio of 2:3and an addition of 3 m L of Span 80.(5)Ni0.85Se/C was used as a photothermal material to investigate the photothermal performance of the material through photothermal warming tests.The photothermal conversion efficiency of the Ni0.85Se/C composite was as high as 62.6%under 808 nm laser irradiation with a power density of 1.0 W·cm-2,and the photothermal warming capacity of the material remained stable under cyclic tests.The Ni0.85Se/C material was also used to construct and test a self-levitating photothermal water evaporation film device.The evaporation rate of the Ni0.85Se/C membrane device was up to 1.147 kg·m-2·h-1 under one solar illumination,corresponding to a photothermal conversion efficiency of 72.30%.The stability test showed that the evaporation rate of the membrane device remained relatively stable,and the water evaporation rate was not seriously affected by the change of water quality under the simulated seawater test.In this paper,studies on photothermal warming and evaporation of solar photothermal water were carried out for nickel selenide and its composites synthesized under different synthetic reaction conditions,providing research ideas for the preparation of nickel selenide nanocomposites with high photothermal conversion efficiency and offering unlimited possibilities for the potential applications and development of photothermal materials. |
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