Preparation And Photothermal Functiona Of Carbon Nanosponge

In this paper,a novel integrated design is proposed,which utilizes carbon nanotubes grown between graphite layers to construct a photothermal unit and further assemble to form a carbon nanosponge with photothermal effect.Defect-free carbon nanonetworks with high thermal conductivity were obtained,avoiding harsh chemical treatment processes.Utilizing novel graphite intercalation compounds as photothermal units improves mechanical stability,prevents separation of photothermal units during cycling,provides higher photothermal heating rates,and provides opportunities for the development of next-generation photothermal adsorbents revelation.The specific research work of this paper is carried out in three aspects:the preparation and performance analysis of carbon nanosponge,the analysis of the photothermal assisted oil-water separation performance of carbon nanosponge,and the preparation and performance analysis of modified hybrid sponge solar water evaporation materials.The main research contents are as follows:(1)Using natural graphite as a raw material,using ferric chloride molten salt intercalation to prepare a graphite intercalation compound,and then using it as a precursor to form a photothermal unit through chemical vapor deposition;Then,the carbon nanotubes were grown by planktonic method to achieve cross-linking between units,forming a hybrid sponge with a three-dimensional structure.The effects of different sizes of natural graphite on the structure of graphite interlayer compounds were explored.The results showed that when the size of natural graphite was 75μm and the mass ratio of intercalating agent is 1:5,and the reaction time at 400℃for 12 h,a uniform second-order graphite intercalation compound product were obtained.Hybrid sponges were prepared by secondary chemical vapor deposition using graphite interlayer compounds as precursors,ferrocene and dichlorobenzene as catalysts and carbon sources,respectively.Characterization analysis confirms that it has three-dimensional porous morphology,excellent mechanical properties and repeated compressibility.Characterization and performance test results show that the hybrid sponge is composed of a graphite intercalation compound hybrid material in which carbon nanotubes are wrapped in a three-dimensional network of overlapping carbon nanotubes.The hybrid sponge has high porosity(>97%)and excellent mechanical properties(more than 80%of the maximum stress is still retained after 50 cycles of compression).(2)By controlling the content of graphite intercalation compound precursor in the photothermal unit,the photothermal conversion performance of carbon nanosponges was regulated,and the influence on the adsorption capacity of crude oil was further explored.The prepared carbon-based photothermal oil-water separation material has ultra-high hydrophobicity and can effectively adsorb oils and organic solvents in water.Photothermal conversion is used to reduce the viscosity of crude oil to achieve effective adsorption of high-viscosity crude oil.The optimal photothermal conversion performance was obtained when the precursor mass in the hybrid sponge was 0.08 g.Under one sunlight intensity,the oil was rapidly heated to 81°C within 25 s to reduce the viscosity of crude oil,and the adsorption capacity could reach 31.68 g/g.And after ten times of recycling,it can still maintain more than 80%of the adsorption capacity.(3)The optimized hybrid sponge was used to control the hydrophilicity of the hybrid sponge by oxygen plasma modification treatment,and its photothermal-steam conversion performance was studied.It was found that treating the hybrid sponge with oxygen plasma at a power of 300 W can significantly improve its hydrophilicity.When the treatment time increased,the photothermal conversion performance of the hybrid sponge improved.Under an illumination environment with the intensity of sunlight,the water evaporation of the hybrid sponge was 0.92 kg/m~2 when the plasma treatment time was 600 s.Compared with the direct evaporation of pure water by illumination,the efficiency of the hybrid sponge is about 5.6 times that of direct evaporation,indicating that the modified hybrid sponge material can be applied to the solar water evaporation system.