Preparation Of Novel Interface Photothermal Conversion Materialsand The Study Of TheirApplications

Interfacial photothermal conversion is considered as a new strategy for efficient utilization of solar energy.A lot of studies have been done on the interface photothermal conversion materials,but the current interfacial photothermal conversion materials still have the problems such as low efficiency,high cost,poor durability,poor biocompatibility and few application fields,which limit their real large-scale applications.In this paper,two novel interfacial photothermal conversion materials are fabricated and their photothermal behaviors are investigated.(1)Photothermal spongesThe melamine sponge was used as the substrate,and a thin layer of reduced graphene oxide(rGO)and silver nanoparticles(AgNPs)were assembled on the threedimensional skeleton surface of the sponge by simple dip coating and one-step reduction method to prepare photothermal sponges.The prepared materials were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),fourier transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),water contact angle(WCA)and ultraviolet-visible near-infrared spectroscopy(UV-vis-NIR).The results showed that the modified sponge maintained the porous network structure of the original sponge,and the secondary structure of the original sponge was not destroyed.The sponge skeleton was coated with a thin layer of rGO and evenly distributed AgNPs and AgNPs are presented as Ag0.The photothermal sponge presents hydrophobicity(the water contact Angle is 130°)and exhibits high absorption and anti-reflection characteristics in the light range of 250-2500 nm.Under one-sun irradiation,the evaporation rate of the photothermal sponge floating on the water as a single-la yer structure is 1.21 kg m-2 h-1 and the evaporation efficiency is 86.8%.The fabricated material shows good durability.Moreover,the fabricated sponge has excellent adsorption capacity to organic solvent and low viscosity oil(54.0-123.0 g/g).For heavy crude oil,the photothermal sponge shows a high adsorption capacity of 68.0 g/g under one-sun irradiation for 5 minutes,which is 7.5 times more than without sunlight.(2)Photothermal hydrogelThe photothermal hydrogel materials were prepared by simple mixing graphite powder(GP)and polyvinyl alcohol(PVA)followed by a frozen cross-link procedure.The fabricated materials were characterized by scanning electron microscopy(SEM),rheometer,fourier transform infrared spectroscopy(FT-IR),dynamic swelling experiment and ultraviolet-visible near-infrared spectroscopy(UV-vis-NIR).The results showed that the photohydrothermal gel has abundant capillary network structure.The composite hydrogel has a crosslinked polymer skeleton,with GP permeated.By changing the ratio of GP/PVA,the water management and water transport capacity of photothermal hydrogel can be adjusted.An appropriate ratio of graphite powder with hydrogel can achieve high absorption of the solar spectrum.The hydrophilic hydrogels and two-dimensional water supply components were combined to form an all-in-one structure which could achieve a high evaporation rate of 1.74 kg m-2 h-1 under one-sun irradiation.The photothermal hydrogels are durable and can efficiently produce pure water under different water environments.