TiO2 nanomaterial is promising with its high potential and outstanding performance in photocatalytic environmental applications, such as CO2 conversion, water treatment, and air quality control. For many of these appl...TiO2 nanomaterial is promising with its high potential and outstanding performance in photocatalytic environmental applications, such as CO2 conversion, water treatment, and air quality control. For many of these applications, the particle size, crystal structure and phase, porosity, and surface area influence the activity of TiO2 dramatically. TiO2 nanomaterials with special structures and morphologies, such as nanospheres, nanowires, nanotubes, nanorods, and nanoflowers are thus synthesized due to their desired characteristics. With an emphasis on the different morphologies of TiO2 and the influence factors in the synthesis, this review summarizes fourteen TiO2 preparation methods, such as the sol-gel method, solvothermal method, and reverse micelle method. The TiO2 formation mechanisms, the advantages and disadvantages of the preparation methods, and the photocatalytic environmental application examples are proposed as well.展开更多
TiO_(2)纳米材料因其存在高的光生电子-空穴对复合速率、电子迁移率低、导电性差以及可逆容量低等问题,使其在光催化和电化学等领域的应用受到限制。MXene(M n+1 X n T x)作为一种新型的二维过渡金属碳化物、氮化物或碳氮化物,具有独特...TiO_(2)纳米材料因其存在高的光生电子-空穴对复合速率、电子迁移率低、导电性差以及可逆容量低等问题,使其在光催化和电化学等领域的应用受到限制。MXene(M n+1 X n T x)作为一种新型的二维过渡金属碳化物、氮化物或碳氮化物,具有独特的二维层状结构、良好的金属导电性和较高的载流子迁移率等特性,将其引入TiO_(2)纳米材料中构建TiO_(2)/MXene纳米复合材料,利用两者的协同作用可进一步提高光电性能。本文从TiO_(2)纳米材料的角度出发,系统综述了零维、一维和二维TiO_(2)与MXene纳米复合材料的可控制备、结构性能及在光催化和电化学领域应用的最新研究进展,并着重介绍了纳米复合材料的构筑机理及MXene对提高TiO_(2)的光催化和电化学性能的增强机制等,分析了目前TiO_(2)/MXene复合材料的制备及其在光催化和电化学领域应用中存在的不足。此外,从优化制备工艺、提升性能和探索相应的性能增强机制等方面对未来TiO_(2)/MXene复合材料的研究方向进行了展望。展开更多
Due to their high anisotropy and chemical functions,two-dimensional(2D)nanomaterials have attracted increasing interest and attention from various scientific fields,including functional electronics,catalysis,supercapa...Due to their high anisotropy and chemical functions,two-dimensional(2D)nanomaterials have attracted increasing interest and attention from various scientific fields,including functional electronics,catalysis,supercapacitors,batteries and energy materials.In the biomedical field,2D nanomaterials have made significant contributions to the field of nanomedicine,especially in drug/gene delivery systems,multimodal imaging,biosensing,antimicrobial agents and tissue engineering.2D nanomaterials such as graphene/graphene oxide(GO)/reduced graphene oxide(r GO),silicate clays,layered double hydroxides(LDHs),transition metal dichalcogenides(TMDs),transition metal oxides(TMOs),black phosphorus(BP),graphitic carbon nitride(g-C3N4),hexagonal boron nitride(h-BN),antimonene(AM),boron nanosheets(B NSs)and tin telluride nanosheets(Sn Te NSs)possess excellent physical,chemical,optical and biological properties due to their uniform shapes,high surface-to-volume ratios and surface charge.In this review,we first introduce the properties,structures and synthetic strategies of different configurations of 2D nanomaterials.Recent advances and paradigms of 2D nanomaterials in a variety of biomedical applications,ranging from drug delivery,cancer treatment,bioimaging and tissue engineering to biosensing are discussed afterwards.In the final part,we foresee the development prospects and challenges of 2D nanomaterials after summarizing the research status of ultrathin 2D nanomaterials.展开更多
Two-dimensional(2D)nanomaterials have demonstrated great potential in the field of flexible gas sensing due to their inherent high specific surface areas,unique electronic properties and flexibility property.However,n...Two-dimensional(2D)nanomaterials have demonstrated great potential in the field of flexible gas sensing due to their inherent high specific surface areas,unique electronic properties and flexibility property.However,numerous challenges including sensitivity,selectivity,response time,recovery time,and stability have to be addressed before their practical application in gas detection field.Development of graphene-like 2D/2D nanocomposites as an efficient strategy to achieve high-performance 2D gas sensor has been reported recently.This review aims to discuss the latest advancements in the 2D/2D nanocomposites for gas sensors.We first elaborate the gas-sensing mechanisms and the collective benefits of 2D/2D hybridization as sensor materials.Then,we systematically present the current gas-sensing applications based on different categories of 2D/2D nanocomposites.Finally,we conclude the future prospect of 2D/2D nanocomposites in gas sensing applications.展开更多
In this article, we investigate the predictions of the first principles on structural stability, electronic and mechanical properties of 2D nanostructures: graphene, silicene, germanene and stenane. The electronic ban...In this article, we investigate the predictions of the first principles on structural stability, electronic and mechanical properties of 2D nanostructures: graphene, silicene, germanene and stenane. The electronic band structure and density of states in all these 2D materials are found to be generic in nature. A small band gap is generated in all the reported materials other than graphene. The linearity at the Dirac cone changes to quadratic, from graphene to stenane and a perfect semimetalicity is exhibited only by graphene. All other 2D structures tend to become semiconductors with an infinitesimal band gap. Bonding characteristics are revealed by density of states histogram, charge density contour, and Mulliken population analysis. Among all 2D materials graphene exhibits exotic mechanical properties. Analysis by born stability criteria and the calculation of formation enthalpies envisages the structural stability of all the structures in the 2D form. The calculated second order elastic stiffness tensor is used to determine the moduli of elasticity in turn to explore the mechanical properties of all these structures for the prolific use in engineering science. Graphene is found to be the strongest material but brittle in nature. Germanene and stenane exhibit ductile nature and hence could be easily incorporated with the existing technology in the semiconductor industry on substrates.展开更多
The topic of superlubricity is attracting considerable interest around the world while humanity is facing an energy crisis.Since various liquid superlubricity systems can be commonly achieved on the macroscale in ambi...The topic of superlubricity is attracting considerable interest around the world while humanity is facing an energy crisis.Since various liquid superlubricity systems can be commonly achieved on the macroscale in ambient conditions,it is considered an effective solution to reduce unnecessary energy and material losses.However,certain practical problems such as low load-bearing pressure,dependence on hydrogen ions,and relatively long running-in processes still limit its widespread application.Two-dimensional(2D)nano-additives with ultrathin longitudinal dimensions can lower the shear resistance between sliding solid surfaces,and thus further optimize the applied conditions.In this review,the latest studies on 2D nano-additives with a combination of various water-based lubricants in the state of superlubricity are reported,typically including black phosphorus(BP),graphene oxide(GO),and layered double hydroxide.During the sliding process,composite lubricants effectively improved the load capacity(up to 600 MPa),reduced wear,and accelerated the running-in period(within 1,000 s)of the liquid superlubricity system.Both macromechanical experiments and microscopic tests are conducted to precisely analyze various interactions at the interfaces of the nano-additives and solid surfaces.These interactions can be described as tribochemical reactions,physical protection,and adsorption enhancement,and improved wear resistance.This review provides better guidance for applying 2D nanomaterials in liquid superlubricity systems.展开更多
基金the supports from the Clean Coal ProgramSchool of Energy Resources in Wyoming
文摘TiO2 nanomaterial is promising with its high potential and outstanding performance in photocatalytic environmental applications, such as CO2 conversion, water treatment, and air quality control. For many of these applications, the particle size, crystal structure and phase, porosity, and surface area influence the activity of TiO2 dramatically. TiO2 nanomaterials with special structures and morphologies, such as nanospheres, nanowires, nanotubes, nanorods, and nanoflowers are thus synthesized due to their desired characteristics. With an emphasis on the different morphologies of TiO2 and the influence factors in the synthesis, this review summarizes fourteen TiO2 preparation methods, such as the sol-gel method, solvothermal method, and reverse micelle method. The TiO2 formation mechanisms, the advantages and disadvantages of the preparation methods, and the photocatalytic environmental application examples are proposed as well.
文摘TiO_(2)纳米材料因其存在高的光生电子-空穴对复合速率、电子迁移率低、导电性差以及可逆容量低等问题,使其在光催化和电化学等领域的应用受到限制。MXene(M n+1 X n T x)作为一种新型的二维过渡金属碳化物、氮化物或碳氮化物,具有独特的二维层状结构、良好的金属导电性和较高的载流子迁移率等特性,将其引入TiO_(2)纳米材料中构建TiO_(2)/MXene纳米复合材料,利用两者的协同作用可进一步提高光电性能。本文从TiO_(2)纳米材料的角度出发,系统综述了零维、一维和二维TiO_(2)与MXene纳米复合材料的可控制备、结构性能及在光催化和电化学领域应用的最新研究进展,并着重介绍了纳米复合材料的构筑机理及MXene对提高TiO_(2)的光催化和电化学性能的增强机制等,分析了目前TiO_(2)/MXene复合材料的制备及其在光催化和电化学领域应用中存在的不足。此外,从优化制备工艺、提升性能和探索相应的性能增强机制等方面对未来TiO_(2)/MXene复合材料的研究方向进行了展望。
基金supported by the National Natural Science Foundation of China (20601010, 21671013, 21521005, 81871786, 81611130091, and 81702113)the Beijing Natural Science Foundation (2174082)the Fundamental Research Funds for the Central Universities (buctylkxj01, XK1802-6)
文摘Due to their high anisotropy and chemical functions,two-dimensional(2D)nanomaterials have attracted increasing interest and attention from various scientific fields,including functional electronics,catalysis,supercapacitors,batteries and energy materials.In the biomedical field,2D nanomaterials have made significant contributions to the field of nanomedicine,especially in drug/gene delivery systems,multimodal imaging,biosensing,antimicrobial agents and tissue engineering.2D nanomaterials such as graphene/graphene oxide(GO)/reduced graphene oxide(r GO),silicate clays,layered double hydroxides(LDHs),transition metal dichalcogenides(TMDs),transition metal oxides(TMOs),black phosphorus(BP),graphitic carbon nitride(g-C3N4),hexagonal boron nitride(h-BN),antimonene(AM),boron nanosheets(B NSs)and tin telluride nanosheets(Sn Te NSs)possess excellent physical,chemical,optical and biological properties due to their uniform shapes,high surface-to-volume ratios and surface charge.In this review,we first introduce the properties,structures and synthetic strategies of different configurations of 2D nanomaterials.Recent advances and paradigms of 2D nanomaterials in a variety of biomedical applications,ranging from drug delivery,cancer treatment,bioimaging and tissue engineering to biosensing are discussed afterwards.In the final part,we foresee the development prospects and challenges of 2D nanomaterials after summarizing the research status of ultrathin 2D nanomaterials.
基金supported by Zhejiang Provincial Natural Science Foundation of China (No. LY18F010009)Ningbo Natural Science Foundation (No. 2018A610002)
文摘Two-dimensional(2D)nanomaterials have demonstrated great potential in the field of flexible gas sensing due to their inherent high specific surface areas,unique electronic properties and flexibility property.However,numerous challenges including sensitivity,selectivity,response time,recovery time,and stability have to be addressed before their practical application in gas detection field.Development of graphene-like 2D/2D nanocomposites as an efficient strategy to achieve high-performance 2D gas sensor has been reported recently.This review aims to discuss the latest advancements in the 2D/2D nanocomposites for gas sensors.We first elaborate the gas-sensing mechanisms and the collective benefits of 2D/2D hybridization as sensor materials.Then,we systematically present the current gas-sensing applications based on different categories of 2D/2D nanocomposites.Finally,we conclude the future prospect of 2D/2D nanocomposites in gas sensing applications.
文摘In this article, we investigate the predictions of the first principles on structural stability, electronic and mechanical properties of 2D nanostructures: graphene, silicene, germanene and stenane. The electronic band structure and density of states in all these 2D materials are found to be generic in nature. A small band gap is generated in all the reported materials other than graphene. The linearity at the Dirac cone changes to quadratic, from graphene to stenane and a perfect semimetalicity is exhibited only by graphene. All other 2D structures tend to become semiconductors with an infinitesimal band gap. Bonding characteristics are revealed by density of states histogram, charge density contour, and Mulliken population analysis. Among all 2D materials graphene exhibits exotic mechanical properties. Analysis by born stability criteria and the calculation of formation enthalpies envisages the structural stability of all the structures in the 2D form. The calculated second order elastic stiffness tensor is used to determine the moduli of elasticity in turn to explore the mechanical properties of all these structures for the prolific use in engineering science. Graphene is found to be the strongest material but brittle in nature. Germanene and stenane exhibit ductile nature and hence could be easily incorporated with the existing technology in the semiconductor industry on substrates.
基金the National Natural Science Foundation of China(51905294,51527901,and 51875303)the China Postdoc Innovation Talent Support Program(BX20180168)the China Postdoctoral Science Foundation(2019M650654)。
文摘The topic of superlubricity is attracting considerable interest around the world while humanity is facing an energy crisis.Since various liquid superlubricity systems can be commonly achieved on the macroscale in ambient conditions,it is considered an effective solution to reduce unnecessary energy and material losses.However,certain practical problems such as low load-bearing pressure,dependence on hydrogen ions,and relatively long running-in processes still limit its widespread application.Two-dimensional(2D)nano-additives with ultrathin longitudinal dimensions can lower the shear resistance between sliding solid surfaces,and thus further optimize the applied conditions.In this review,the latest studies on 2D nano-additives with a combination of various water-based lubricants in the state of superlubricity are reported,typically including black phosphorus(BP),graphene oxide(GO),and layered double hydroxide.During the sliding process,composite lubricants effectively improved the load capacity(up to 600 MPa),reduced wear,and accelerated the running-in period(within 1,000 s)of the liquid superlubricity system.Both macromechanical experiments and microscopic tests are conducted to precisely analyze various interactions at the interfaces of the nano-additives and solid surfaces.These interactions can be described as tribochemical reactions,physical protection,and adsorption enhancement,and improved wear resistance.This review provides better guidance for applying 2D nanomaterials in liquid superlubricity systems.
