Preparation And Application Of Photothermal Conversion Materials With Three-dimensional Biological Structure

It is meaningful to develop efficient and clean renewable energy as the world is facing the global energy crisis and environmental pollution.As the most widespread renewable energy,solar energy has the potential to meet the energy needs of the world and promote the sustainable development of the world.Solar energy can be divided into thermal energy(photothermal),electrical energy(photoelectricity),and chemical energy(photocatalysis)according to the conversion form.In these technologies,photothermal conversion is a direct conversion process that has achieved the highest conversion efficiency.The photothermal effect has been used as a new strategy to enhance water evaporation and catalytic performance.Traditional photothermal materials include plasmon metal nanoparticles,semiconductor materials,and carbon materials.Both plasmon metal nanoparticles and semiconductor materials are not only complicated and costly to prepare,but also have obvious differences in the absorption of the full spectrum and stability compared with carbon materials.The preparation method for artificial carbon material mainly include"bottom-up"chemical self-assembly or"top-down"physical processing method,which are not only difficult to balance cost and efficiency,but also difficult to construct the micro-nano structure with fine three-dimensional configuration.After billions of years of evolution,organisms in nature have evolved various complex and delicate microstructures,organisms with different microstructures have different functional characteristics.Therefore,how to select biomass carbon materials with specific microstructures has attracted great interest in the field of photothermal.By combining artificial materials with biological carbon materials with fine hierarchical structure,while utilizing the photothermal properties of biomass carbon materials.The related properties of artificial materials such as catalysis are given to meet the application requirements of photothermal catalysis,photothermal therapy and other fields.In this study,sugarcane,bamboo,and wood with a variety of different micro-fine functional structures were selected and used as templates to prepare surface carbonized sugarcane,surface carbonized bamboo,and carbonized wood/2D Sn Se Quantum dot composite with different biological fine hierarchical structures.Then study their performance in the field of photothermal water evaporation and photothermal catalysis,achieving high energy conversion efficiency.Finally,the mechanism for the functional characteristics of fine-structured organisms and their photothermal properties to improve the performance are discussed in detail.The main results are as follows:(1)The surface-carbonized sugarcane with de-sugaring while retaining sugarcane microstructure was obtained by using sugarcane as a template followed by freeze-drying,slicing,and subsequent surface carbonization.The morphology,pore structure distribution,optical properties,and surface hydrophobicity were studied.Then the surface carbonized sugarcane was used as the photothermal water evaporation material in the water evaporation process.The experimental results show that the surface carbonized sugarcane has a 98%full spectral absorption rate and good hydrophilicity in sample's surface.The internal natural water transmission channel-vascular bundle can work as a very good water transmission channel in evaporation process.The internal sugar storage cavity-parenchyma cells can work as a very good thermal insulation.As a result,the surface carbonized sugarcane can achieve the evaporation efficiency up to 87.4%under one sun illumination,surpassing most of the biomass-based photothermal water evaporation materials reported ever.This finding shows that the multi-functional surface carbonized sugarcane has a higher photothermal conversion efficiency than the traditional wood-based photothermal water evaporation material.It also provides ideas for designing photothermal water evaporation materials with dual function structure.(2)Furthermore,we use another herbaceous plant-bamboo as a template,and study the effects of macroscopic biological configuration on the performance of photothermal water evaporation.The surface carbonized bamboo that retains the microstructure of the bamboo was obtained through simple sectioning and surface carbonization by using the bamboo as a template.The microscopic morphology,pore structure,and optical properties were studied,and the groove structure was designed on the upper surface of the sample.The experimental results show that the surface carbonized bamboo with groove structure shows higher photothermal water evaporation rate and photothermal conversion efficiency(photothermal water evaporation efficiency is 93%and 78%,respectively)than the bamboo without groove structure on the upper surface.The bamboo with a groove structure on the experimental surface has higher photothermal water evaporation efficiency,due to the groove structure on the upper surface can simultaneously collect water and heat,which is beneficial to the evaporation of photothermal water.Bamboo not only has the micro-functional structure of wood and sugarcane,but also has a macroscopic hollow structure and a groove structure on the upper surface,so its performance can reach 93%.This work provides a reference for the construction of photothermal water evaporation materials with multi-scale functional structures.(3)In order to further utilize the photothermal materials with three-dimensional biological structure,Sn Se quantum dots/3D wood configuration composite material was constructed by using wood as template.Sn Se quantum dots with a single layer thickness were obtained by assembling lithium ion batteries,using innovative constant current and constant voltage electrochemical lithium intercalation methods,followed by subsequent liquid phase exfoliation.The exfoliated Sn Se quantum dots were studied among their micro-morphology,crystal structure,chemical composition and electrochemical ammonia production performance.The experimental results show that the size and thickness of the exfoliated tin selenide quantum dots are significantly reduced compared to the precursors,and their chemical composition has hardly changed.The electrochemical performance of electrochemical reduction of nitrogen to produce ammonia is well.Under atmospheric conditions,and while in 0.1 M HCl,its electrocatalytic ammonia production efficiency and Faraday efficiency can reach 61?g h^-1 mg^-1 and 12.14%,respectively,which exceeds most reported electrochemical catalytic nitrogen reduction for ammonia production catalyst.Its excellent electrocatalytic ammonia production performance is attributed to the exposure of more active surfaces?active sites and defects produced in the process of lithium intercalation.This study not only demonstrates that the 2D-Sn Se is efficient for nitrogen reduction reaction,but also provides a method for the preparation of basic elements for the study of biological configuration materials.A wood-based electrode sheet was obtained by slicing and carbonizing wood as the template.The Sn Se quantum dots prepared through lithium intercalation plus exfoliation were laminated on the wood electrode to obtain the composite of wood/Sn Se quantum dots.Among them,the carbonized wood chips play the role for photothermal,while Sn Se quantum dots play the role for catalysis.The performance of electrocatalytic ammonia production with and without light was studied.The experimental results show that the electrocatalytic ammonia yield and Faradic efficiency of the composite electrode is higher under the light irradiation(83.70?g h^-1mg^-1and 1.75%,respectively)than without light irradiation(59.78?g h^-1 mg^-1and0.66%,respectively),which indicates that photothermal promotes the electrocatalytic ammonia production.This study was inspired by nature and explore its application prospects in energy conversion directions such as photothermal water evaporation and photothermal electrocatalytic nitrogen reduction by using natural plant bodies such as sugarcane,bamboo,and wood with a hierarchical multi-scale functional structure as templates.The materials provide scientific basis for related functionalization research,and provide references for the preparation of materials with high photothermal water evaporation efficiency and higher electrocatalytic ammonia production efficiency.