Thermoelectric generators have attracted a wide research interest owing to their ability to directly convert heat into electrical power.Moreover,the thermoelectric properties of traditional inorganic and organic mater...Thermoelectric generators have attracted a wide research interest owing to their ability to directly convert heat into electrical power.Moreover,the thermoelectric properties of traditional inorganic and organic materials have been significantly improved over the past few decades.Among these compounds,layered two-dimensional(2D)materials,such as graphene,black phosphorus,transition metal dichalcogenides,IVA–VIA compounds,and MXenes,have generated a large research attention as a group of potentially high-performance thermoelectric materials.Due to their unique electronic,mechanical,thermal,and optoelectronic properties,thermoelectric devices based on such materials can be applied in a variety of applications.Herein,a comprehensive review on the development of 2D materials for thermoelectric applications,as well as theoretical simulations and experimental preparation,is presented.In addition,nanodevice and new applications of 2D thermoelectric materials are also introduced.At last,current challenges are discussed and several prospects in this field are proposed.展开更多
Two-dimensional black phosphorus(2D BP),an emerging material,has aroused tremendous interest once discovered.This is due to the fact that it integrates unprecedented properties of other 2D materials,such as tunable ba...Two-dimensional black phosphorus(2D BP),an emerging material,has aroused tremendous interest once discovered.This is due to the fact that it integrates unprecedented properties of other 2D materials,such as tunable bandgap structures,outstanding electrochemical properties,anisotropic mechanical,thermodynamic,and photoelectric properties,making it of great research value in many fields.The emergence of 2D BP has greatly promoted the development of electrochemical energy storage devices,especially lithium-ion batteries.However,in the application of 2D BP,there are still some problems to be solved urgently,such as the difficulty in the synthesis of large-scale high-quality phosphorene,poor environmental stability,and the volume expansion as electrode materials.Herein,according to the latest research progress of 2D BP in the field of energy storage,we systematically summarize and compare the preparation methods of phosphorene and discuss the basic structure and properties of BP,especially the environmental instability and passivation techniques.In particular,the practical application and challenges of 2D BP as anode material for lithium-ion batteries are analyzed in detail.Finally,some personal perspectives on the future development and challenges of BP are presented.展开更多
Replacing platinum for catalyzing hydrogen evolution reaction （HER） in acidic medium remains great chal- lenges. Herein, we prepared few-layered MoS2 by ball milling as an efficient catalyst for HER in acidic medium...Replacing platinum for catalyzing hydrogen evolution reaction （HER） in acidic medium remains great chal- lenges. Herein, we prepared few-layered MoS2 by ball milling as an efficient catalyst for HER in acidic medium, The activity of as-prepared MoS2 had a strong dependence on the ball milling time, Furthermore, Ketjen Black EC 300J was added into the ball-milled MoS2 followed by a second ball milling, and the resultant MoS2/carbon black hybrid material showed a much higher HER activity than MoS2 and carbon black alone. The enhanced activity of the MoS2/carbon black hybrid material was attributed to the increased abundance of catalytic edge sites of MoS） and excellent electrical coupling to the underlving carbon network.展开更多
The band structure, density of states, optical properties, carrier mobility, and loss function of graphene, black phosphorus（BP）, and molybdenum disulfide（MoS_2） were investigated by the first-principles method wi...The band structure, density of states, optical properties, carrier mobility, and loss function of graphene, black phosphorus（BP）, and molybdenum disulfide（MoS_2） were investigated by the first-principles method with the generalized-gradient approximation. The graphene was a zero-band-gap semiconductor. The band gaps of BP and MoS_2 were strongly dependent on the number of layers. The relationships between layers and band gap were built to predict the band gap of few-layer BP and MoS_2. The absorption showed an explicit anisotropy for light polarized in（1 0 0） and（0 0 1） directions of graphene, BP,and MoS_2. This behavior may be readily detected in spectroscopic measurements and exploited for optoelectronic applications. Moreover, graphene（5.27 × 10~4 cm^2·V^（-1）·s^（-1））, BP（1.5 × 10~4 cm^2·V^（-1）·s^（-1））, and MoS_2（2.57×102 cm2·V-1·s-1）have high carrier mobility. These results show that graphene, BP, and MoS_2 are promising candidates for future electronic applications.展开更多
The generation of green hydrogen(H_2) energy is of great significance to solve worldwide energy and environmental issues. Reduced Ti based photocatalyst has recently attracted intensive attention due to its excellent ...The generation of green hydrogen(H_2) energy is of great significance to solve worldwide energy and environmental issues. Reduced Ti based photocatalyst has recently attracted intensive attention due to its excellent photocatalytic activity, while the synthesis of reduced Ti based photocatalysts with high stability is still a great challenge. Here, we report a facile method for synthesis of reduced Ti metal organic frameworks(small amounts of Pt incorporated) encapsulated BP(BP/R-Ti-MOFs/Pt) hybrid nanomaterial with enhanced photocatalytic activity. The strong interaction between Ti and P reduces the valence state of the binding Ti^(4+)on the BP surface, forming abundant reduced Ti^(4+)within R-Ti-MOFs/BP. Such reduced Ti^(4+)render R-Ti-MOFs/BP efficient charge transfer and excellent light absorption capability, thus promote the photocatalytic H_2 production efficiency. Furthermore, the Ti-P interaction stabilizes both reduced Ti^(4+)and BP during the photocatalytic reaction, which greatly enhanced the stability of the obtained BP/R-TiMOFs/Pt photocatalyst.展开更多
Hybrid organic-inorganic perovskite solar cells(PSCs) are considered to be the most promising thirdgeneration photovoltaic(PV) technology with the most rapid rate of increase in the power conversion efficiency(PCE). T...Hybrid organic-inorganic perovskite solar cells(PSCs) are considered to be the most promising thirdgeneration photovoltaic(PV) technology with the most rapid rate of increase in the power conversion efficiency(PCE). To date, their PCE values are comparable to the established photovoltaic technologies such as crystalline silicon. Intensive research activities associated with PSCs have been being performed,since 2009, aiming to further boost the device performance in terms of efficiency and stability via different strategies in order to accelerate the progress of commercialization. The emerging 2 D black phosphorus(BP) is a novel class of semiconducting material owing to its unique characteristics, allowing them to become attractive materials for applications in a variety of optical and electronic devices, which have been comprehensively reviewed in the literature. However, comprehensive reviews focusing on the application of BP in PSCs are scarce in the community. This review discusses the research works with the incorporation of BP as a functional material in PSCs. The methodology as well as the effects of employing BP in different regions of PSCs are summarized. Further challenges and potential research directions are also highlighted.展开更多
The heartwood of teak in certain areas of Java Island displays irregular black streaks along the annual rings. We investigated the color and chemical characteristics in a radial direction of partially black-streaked h...The heartwood of teak in certain areas of Java Island displays irregular black streaks along the annual rings. We investigated the color and chemical characteristics in a radial direction of partially black-streaked heartwood samples. Color properties （pH value, inorganic element, extractive content and extractive characterization） were measured in the color co-ordinates CIELAB system. The results show that the black streak part was 12-15 brightness （L^＊） value units less than the normal heartwood. Furthermore, the black streak part had more red （a^＊） but less yellow （b^＊）, hue （h） and chroma （C^＊） than the normal wood. The pH value, ash content and calcium contents of the black streak part were slightly higher than those obtained for the normal wood. The content of the low-polar extractive （n-hexane and ethyl acetate） of the black streak part was considerably higher than that for the normal wood. The blackening process was speculated to be a kind of defense mechanism indicated by remarkable amount ofbioactive compound called tectoquinone.展开更多
Tests of the candidate plasma facing materials（PFMs） used in experimental fusion devices are essential due to the direct influence of in-situ plasma loading.A type of ultrafine grained（UFG） tungsten sintered by re...Tests of the candidate plasma facing materials（PFMs） used in experimental fusion devices are essential due to the direct influence of in-situ plasma loading.A type of ultrafine grained（UFG） tungsten sintered by resistance sintering under ultra-high pressure（RSUHP） method has been exposed in the edge plasma of the HT-7 tokamak to investigate its performance under plasma loading.Under cychc edge plasma loading,the UFG tungsten develops both macro and micro cracks.The macro cracks are attributed to the low temperature brittleness of the tungsten material itself,while the micro cracks are generated from local intense power flux deposition.展开更多
基金supported by National Science Foundation for Young Scientists of China (No.61905161 and 51702219)the National Natural Science Foundation of China (No.61975134,61875138 and 61775147)+1 种基金the Science and Technology Innovation Commission of Shenzhen (No. JCYJ20180206121837007)the Shenzhen Nanshan District Pilotage Team Program (LHTD20170006)
文摘Thermoelectric generators have attracted a wide research interest owing to their ability to directly convert heat into electrical power.Moreover,the thermoelectric properties of traditional inorganic and organic materials have been significantly improved over the past few decades.Among these compounds,layered two-dimensional(2D)materials,such as graphene,black phosphorus,transition metal dichalcogenides,IVA–VIA compounds,and MXenes,have generated a large research attention as a group of potentially high-performance thermoelectric materials.Due to their unique electronic,mechanical,thermal,and optoelectronic properties,thermoelectric devices based on such materials can be applied in a variety of applications.Herein,a comprehensive review on the development of 2D materials for thermoelectric applications,as well as theoretical simulations and experimental preparation,is presented.In addition,nanodevice and new applications of 2D thermoelectric materials are also introduced.At last,current challenges are discussed and several prospects in this field are proposed.
基金the national science foundation of China(Nos.21373074 and 61675061)。
文摘Two-dimensional black phosphorus(2D BP),an emerging material,has aroused tremendous interest once discovered.This is due to the fact that it integrates unprecedented properties of other 2D materials,such as tunable bandgap structures,outstanding electrochemical properties,anisotropic mechanical,thermodynamic,and photoelectric properties,making it of great research value in many fields.The emergence of 2D BP has greatly promoted the development of electrochemical energy storage devices,especially lithium-ion batteries.However,in the application of 2D BP,there are still some problems to be solved urgently,such as the difficulty in the synthesis of large-scale high-quality phosphorene,poor environmental stability,and the volume expansion as electrode materials.Herein,according to the latest research progress of 2D BP in the field of energy storage,we systematically summarize and compare the preparation methods of phosphorene and discuss the basic structure and properties of BP,especially the environmental instability and passivation techniques.In particular,the practical application and challenges of 2D BP as anode material for lithium-ion batteries are analyzed in detail.Finally,some personal perspectives on the future development and challenges of BP are presented.
基金the financial support from the Ministry of Science and Technology of China (grants 2012CB215500 and 2013CB933100)the National Natural Science Foundation of China (grants 21573222 and 21103178)
文摘Replacing platinum for catalyzing hydrogen evolution reaction （HER） in acidic medium remains great chal- lenges. Herein, we prepared few-layered MoS2 by ball milling as an efficient catalyst for HER in acidic medium, The activity of as-prepared MoS2 had a strong dependence on the ball milling time, Furthermore, Ketjen Black EC 300J was added into the ball-milled MoS2 followed by a second ball milling, and the resultant MoS2/carbon black hybrid material showed a much higher HER activity than MoS2 and carbon black alone. The enhanced activity of the MoS2/carbon black hybrid material was attributed to the increased abundance of catalytic edge sites of MoS） and excellent electrical coupling to the underlving carbon network.
基金Project supported by the National Key R&D Program of China(Grant No.2017YFB0305800)
文摘The band structure, density of states, optical properties, carrier mobility, and loss function of graphene, black phosphorus（BP）, and molybdenum disulfide（MoS_2） were investigated by the first-principles method with the generalized-gradient approximation. The graphene was a zero-band-gap semiconductor. The band gaps of BP and MoS_2 were strongly dependent on the number of layers. The relationships between layers and band gap were built to predict the band gap of few-layer BP and MoS_2. The absorption showed an explicit anisotropy for light polarized in（1 0 0） and（0 0 1） directions of graphene, BP,and MoS_2. This behavior may be readily detected in spectroscopic measurements and exploited for optoelectronic applications. Moreover, graphene（5.27 × 10~4 cm^2·V^（-1）·s^（-1））, BP（1.5 × 10~4 cm^2·V^（-1）·s^（-1））, and MoS_2（2.57×102 cm2·V-1·s-1）have high carrier mobility. These results show that graphene, BP, and MoS_2 are promising candidates for future electronic applications.
基金financially supported by the National Natural Science Foundation of China (21771154, 31371005)the Shenzhen Fundamental Research Programs (JCYJ20190809161013453)+1 种基金the Natural Science Foundation of Fujian Province of China (Nos. 2018J01019, 2018J05025)the Fundamental Research Funds for the Central Universities (20720180019, 20720180016)。
文摘The generation of green hydrogen(H_2) energy is of great significance to solve worldwide energy and environmental issues. Reduced Ti based photocatalyst has recently attracted intensive attention due to its excellent photocatalytic activity, while the synthesis of reduced Ti based photocatalysts with high stability is still a great challenge. Here, we report a facile method for synthesis of reduced Ti metal organic frameworks(small amounts of Pt incorporated) encapsulated BP(BP/R-Ti-MOFs/Pt) hybrid nanomaterial with enhanced photocatalytic activity. The strong interaction between Ti and P reduces the valence state of the binding Ti^(4+)on the BP surface, forming abundant reduced Ti^(4+)within R-Ti-MOFs/BP. Such reduced Ti^(4+)render R-Ti-MOFs/BP efficient charge transfer and excellent light absorption capability, thus promote the photocatalytic H_2 production efficiency. Furthermore, the Ti-P interaction stabilizes both reduced Ti^(4+)and BP during the photocatalytic reaction, which greatly enhanced the stability of the obtained BP/R-TiMOFs/Pt photocatalyst.
基金the Scientific Research Grant from Ministry of Education and Science of the Republic of Kazakhstan(AP08856931)the Nazarbayev University(110119FD4506,021220CRP0422)。
文摘Hybrid organic-inorganic perovskite solar cells(PSCs) are considered to be the most promising thirdgeneration photovoltaic(PV) technology with the most rapid rate of increase in the power conversion efficiency(PCE). To date, their PCE values are comparable to the established photovoltaic technologies such as crystalline silicon. Intensive research activities associated with PSCs have been being performed,since 2009, aiming to further boost the device performance in terms of efficiency and stability via different strategies in order to accelerate the progress of commercialization. The emerging 2 D black phosphorus(BP) is a novel class of semiconducting material owing to its unique characteristics, allowing them to become attractive materials for applications in a variety of optical and electronic devices, which have been comprehensively reviewed in the literature. However, comprehensive reviews focusing on the application of BP in PSCs are scarce in the community. This review discusses the research works with the incorporation of BP as a functional material in PSCs. The methodology as well as the effects of employing BP in different regions of PSCs are summarized. Further challenges and potential research directions are also highlighted.
基金supported by the Ministry of Educa-tion, Culture, Sports, Science and Technology in Japan.
文摘The heartwood of teak in certain areas of Java Island displays irregular black streaks along the annual rings. We investigated the color and chemical characteristics in a radial direction of partially black-streaked heartwood samples. Color properties （pH value, inorganic element, extractive content and extractive characterization） were measured in the color co-ordinates CIELAB system. The results show that the black streak part was 12-15 brightness （L^＊） value units less than the normal heartwood. Furthermore, the black streak part had more red （a^＊） but less yellow （b^＊）, hue （h） and chroma （C^＊） than the normal wood. The pH value, ash content and calcium contents of the black streak part were slightly higher than those obtained for the normal wood. The content of the low-polar extractive （n-hexane and ethyl acetate） of the black streak part was considerably higher than that for the normal wood. The blackening process was speculated to be a kind of defense mechanism indicated by remarkable amount ofbioactive compound called tectoquinone.
基金supported by the Key Project of Chinese Academy of Sciences(No.KJCX2-YW-N35)National Natural Science Foundation of China(No.11175205)
文摘Tests of the candidate plasma facing materials（PFMs） used in experimental fusion devices are essential due to the direct influence of in-situ plasma loading.A type of ultrafine grained（UFG） tungsten sintered by resistance sintering under ultra-high pressure（RSUHP） method has been exposed in the edge plasma of the HT-7 tokamak to investigate its performance under plasma loading.Under cychc edge plasma loading,the UFG tungsten develops both macro and micro cracks.The macro cracks are attributed to the low temperature brittleness of the tungsten material itself,while the micro cracks are generated from local intense power flux deposition.
