Three-dimensional graphene-based aerogels have promising applications in oil adsorption and environmental restoration.However,current research of graphene-based aerogels is often hindered by high preparation cost,poor...Three-dimensional graphene-based aerogels have promising applications in oil adsorption and environmental restoration.However,current research of graphene-based aerogels is often hindered by high preparation cost,poor mechanical properties and low recycling efficiency.Here,superelastic graphene aerogel(SGA)was prepared through one-step freezing and twice hydrothermal reduction followed by drying under ambient pressure.The simple atmospheric drying provides a possibility for large-scale preparation of high performance graphene-based aerogels.The prepared SGA not only has the ability of highly repeatable compression rebound,but also exhibits excellent oil adsorption performance.And the overall performance of SGA is better than most of graphenebased aerogels prepared by freeze drying.After the SGA was cyclically compressed with 70%strain for 300 times,it can return to the original shape and height substantially.SGA retained about 90%of the initial adsorption capacity after 50 cycles of adsorption and compression regeneration for cyclohexane.展开更多
A simple,fast and cost-effective method for monolithic carbon aerogels(CAs) preparation was proposed through sol-gel polycondensation of resorcinol with fo rmaldehyde in a basic aqueous solution followed by ambient pr...A simple,fast and cost-effective method for monolithic carbon aerogels(CAs) preparation was proposed through sol-gel polycondensation of resorcinol with fo rmaldehyde in a basic aqueous solution followed by ambient pressure drying without solvent exchange,and carbonization.The microstructure and network strength of CAs were tailored by adju sting the catalyst concentration([resorcinol]/[sodium carbonate] in the range of 300-2000),water content([deionized water]/[resorcinol] equals to 17 and 24,respectively),and gelation temperature(Tgel in the range of 30-90℃).Resultantly,the CAs with a wide range of density(0.30-1.13 g/cm3),high specific surface area(465-616 m2/g),high compressive strength(6.5-147.4 MPa)and low thermal conductivity(0.065-0.120 W·m-1 K-1) were obtained in this work.Moreover,the largesized CAs(100×100×20 mm3) can also be prepared by this method since the formed robust skeleton network can resist shrinkage/collapse of pore structure and prevent cracking during drying.The improved mechanical strength and monolithic forming abilities could be mainly attributed to the uniform arrangement of carbon particles and pores,fine particle size,abundant network structure and enhanced particle neck.展开更多
Here we present an economical ambient pressure drying method of preparing monolithic silica aerogels from methyltrimethoxysilane precursor while using sodium bicarbonate solution as the exchanging solvent.We prepared ...Here we present an economical ambient pressure drying method of preparing monolithic silica aerogels from methyltrimethoxysilane precursor while using sodium bicarbonate solution as the exchanging solvent.We prepared silica aerogels with a density and a specific surface area of 0.053 g·cm^(-3) and 423 m^(2)·g^(-1) respectively.The average pore diameter of silica aerogels is 23 nm as the pore specific volume is 1.11 cm^(3)·g^(-1),Further,the contact angle between water droplet and the surface of silica aerogels in specific condition can be as high as 166°,which indicates a super-hydrophobic surface of aerogels.展开更多
Titanium oxides have been considered promising anode materials for lithium-ion batteries(LIBs).However,the poor conductivity and low specific capacity of bulk titanium oxides limit their application.In this study,a ca...Titanium oxides have been considered promising anode materials for lithium-ion batteries(LIBs).However,the poor conductivity and low specific capacity of bulk titanium oxides limit their application.In this study,a carbon dot-modified TiO_(2)@SiO_(2)aerogel was successfully fabricated through a facile ambient pressure drying strategy and used as an anode material of LIBs.Benefiting from the crosslinking of carbon dots and the surface modification of SiO_(2),the as-prepared hierarchical aerogel exhibited a high initial discharge capacity of 974 mAh g^(−1)and maintained a capacity of 299 mAh g^(−1)after 100 cycles at 0.1 A g^(−1).It also retained a discharge capacity of 111 mAh g^(−1)with a CE of 99.9%at 3 A g^(−1).The carbon dot-modified cross-linking skeleton contributes to the structural integrity of the TiO_(2)@SiO_(2)aerogel during repeated insertion/extraction of lithium ions,guaranteeing outstanding cycling and high-rate performance.This ambient pressure drying strategy provides a facile and feasible way to produce high-performance aerogel anode materials for lithium-ion storage.展开更多
基金the financial support of National Natural Science Foundation of China (22078366)
文摘Three-dimensional graphene-based aerogels have promising applications in oil adsorption and environmental restoration.However,current research of graphene-based aerogels is often hindered by high preparation cost,poor mechanical properties and low recycling efficiency.Here,superelastic graphene aerogel(SGA)was prepared through one-step freezing and twice hydrothermal reduction followed by drying under ambient pressure.The simple atmospheric drying provides a possibility for large-scale preparation of high performance graphene-based aerogels.The prepared SGA not only has the ability of highly repeatable compression rebound,but also exhibits excellent oil adsorption performance.And the overall performance of SGA is better than most of graphenebased aerogels prepared by freeze drying.After the SGA was cyclically compressed with 70%strain for 300 times,it can return to the original shape and height substantially.SGA retained about 90%of the initial adsorption capacity after 50 cycles of adsorption and compression regeneration for cyclohexane.
基金supported by the Major Program of Aerospace Advanced Manufacturing Technology Research Foundation of NSFC and CASC, China Grant No. U1537204National Natural Science Foundation of China Grant No. 51802313 and 51902315+2 种基金National Science and Technology Major Project (2017-VI-0020-0093)Research Fund of Youth Innovation Promotion Association of CAS, China Grant No. 2014171National Key R&D Program of China Grant No. 2018YFF01013600。
文摘A simple,fast and cost-effective method for monolithic carbon aerogels(CAs) preparation was proposed through sol-gel polycondensation of resorcinol with fo rmaldehyde in a basic aqueous solution followed by ambient pressure drying without solvent exchange,and carbonization.The microstructure and network strength of CAs were tailored by adju sting the catalyst concentration([resorcinol]/[sodium carbonate] in the range of 300-2000),water content([deionized water]/[resorcinol] equals to 17 and 24,respectively),and gelation temperature(Tgel in the range of 30-90℃).Resultantly,the CAs with a wide range of density(0.30-1.13 g/cm3),high specific surface area(465-616 m2/g),high compressive strength(6.5-147.4 MPa)and low thermal conductivity(0.065-0.120 W·m-1 K-1) were obtained in this work.Moreover,the largesized CAs(100×100×20 mm3) can also be prepared by this method since the formed robust skeleton network can resist shrinkage/collapse of pore structure and prevent cracking during drying.The improved mechanical strength and monolithic forming abilities could be mainly attributed to the uniform arrangement of carbon particles and pores,fine particle size,abundant network structure and enhanced particle neck.
文摘Here we present an economical ambient pressure drying method of preparing monolithic silica aerogels from methyltrimethoxysilane precursor while using sodium bicarbonate solution as the exchanging solvent.We prepared silica aerogels with a density and a specific surface area of 0.053 g·cm^(-3) and 423 m^(2)·g^(-1) respectively.The average pore diameter of silica aerogels is 23 nm as the pore specific volume is 1.11 cm^(3)·g^(-1),Further,the contact angle between water droplet and the surface of silica aerogels in specific condition can be as high as 166°,which indicates a super-hydrophobic surface of aerogels.
基金supported by the National Key Research and Development Project(2019YFC1907801)the Innovation-Driven Project of Central South University(No.2020CX007).
文摘Titanium oxides have been considered promising anode materials for lithium-ion batteries(LIBs).However,the poor conductivity and low specific capacity of bulk titanium oxides limit their application.In this study,a carbon dot-modified TiO_(2)@SiO_(2)aerogel was successfully fabricated through a facile ambient pressure drying strategy and used as an anode material of LIBs.Benefiting from the crosslinking of carbon dots and the surface modification of SiO_(2),the as-prepared hierarchical aerogel exhibited a high initial discharge capacity of 974 mAh g^(−1)and maintained a capacity of 299 mAh g^(−1)after 100 cycles at 0.1 A g^(−1).It also retained a discharge capacity of 111 mAh g^(−1)with a CE of 99.9%at 3 A g^(−1).The carbon dot-modified cross-linking skeleton contributes to the structural integrity of the TiO_(2)@SiO_(2)aerogel during repeated insertion/extraction of lithium ions,guaranteeing outstanding cycling and high-rate performance.This ambient pressure drying strategy provides a facile and feasible way to produce high-performance aerogel anode materials for lithium-ion storage.
