Preparation And Photothermal Properties Of Carbon-based Solar Absorption Materials

The large-scale application of solar steam evaporation can solve the two major problems of the fossil energy crisis and the shortage of fresh water resources at the same time,and therefore has important research significance.Ideal solar water evaporation material must have the following characteristics at the same time:efficient solar absorption,efficient photothermal conversion,and hydrophilic porous structure to facilitate water transport.In order to obtain efficient solar evaporation materials,carbonized radish,tin oxide antimony?ATO?/C composite membranes,and Ag@Ag₂S/C double-layer composite membrane materials were prepared and the relative properties of the samples were studied.The results are as follows:?1?A high-efficiency steam-generated solar absorber was prepared by carbonization of a white radish which is an inexpensive and widely available crop.The carbonized radish has a highly developed cellular porous structure and excellent hydrophilic characteristics.The solar absorption of the carbonized radish is up to 93.5%within the spectrum from 200 to 2500 nm.Under one-sun illumination,the water evaporation rate of the carbonized radish is as high as 1.57 kg·m^-2·h^-1.The corresponding solar steam generation efficiency is 85.9%.For different types of raw water including seawater and dye wastewater,the water collected by evaporation achieve excellent treatment performance.?2?ATO/C composite membrane materials with directional porous structure were prepared by a freeze-casting/freeze-drying technology,with carboxymethyl cellulose as a carbon precursor and ATO powder as a near-infrared light absorber.When the ratio of ATO:C is 1:1.694,the ATO/C composite can absorb more than 96%of solar energy in the spectral range of 250 to 2500 nm.The resulting ATO/C composite membrane has excellent hydrophilic properties.Under one-sun illumination,the water evaporation rate of the ATO/C composite membrane is as high as 1.12kg·m^-2·h^-1.The corresponding solar steam generation efficiency is 68.9%.For different types of raw water including seawater and dye wastewater,the water collected by evaporation achieve excellent treatment performance.?3?Ag@Ag₂S/C double-layer composite with oriented porous structure was prepared by freeze-casting-freeze drying technique,with carboxymethyl cellulose as a carbon precursor and Ag@Ag₂S core@shell nanoparticles as the enhanced near-infrared light absorbing materials.The double-layer composite absorbs more than89%solar energy in the spectral range of 250-2500 nm and shows excellent hydrophilic characteristics.Under one-sun illumination,the water evaporation rate of the Ag@Ag₂S/C double-layer composite is 1.34 kg·m^-2·h^-1.The corresponding solar steam generation efficiency is 81.5%.For different types of raw water including seawater and dye wastewater,the water collected by evaporation achieve excellent treatment performance.