Van der Waals heterostructure, which consists of various two- dimensional （2D） layered materials stacked along the direction perpendicular to their 2D plane, has emerged as a promising material system for device app...Van der Waals heterostructure, which consists of various two- dimensional （2D） layered materials stacked along the direction perpendicular to their 2D plane, has emerged as a promising material system for device applications in recent years .展开更多
Although bimetallic phosphide cocatalysts have attracted considerable interest in photocatalysis research owing to their advantageous thermodynamic characteristics,superstable and efficient cocatalysts have rarely bee...Although bimetallic phosphide cocatalysts have attracted considerable interest in photocatalysis research owing to their advantageous thermodynamic characteristics,superstable and efficient cocatalysts have rarely been produced through the modulation of their structure and composition.In this study,a series of bimetallic nickel-iron phosphide(Ni_(x)Fe_(2-x)P,where 0<x<2)cocatalysts with controllable structures and overpotentials were designed by adjusting the atomic ratio of Ni/Fe onto nonmetallic elemental red phosphorus(RP)for the photocatalytic selective oxidation of benzyl alcohol(BA)coupled with hydrogen production.The catalysts exhibited an outstanding photocatalytic activity for benzaldehyde and a high H_(2)yield.The RP regulated by bimetallic phosphide cocatalysts(Ni_(x)Fe_(2-x)P)demonstrated higher photocatalytic oxidation-reduction activity than that regulated by monometallic phosphide cocatalysts(Ni_(2)P and Fe2P).In particular,the RP regulated by Ni_(1.25)Fe_(0.75)P exhibited the best photocatalytic performance.In addition,experimental and theoretical calculations further illustrated that Ni_(1.25)Fe_(0.75)P,with the optimized electronic structure,possessed good electrical conductivity and provided strong adsorption and abundant active sites,thereby accelerating electron migration and lowering the reaction energy barrier of RP.This finding offers valuable insights into the rational design of highly effective cocatalysts aimed at optimizing the photocatalytic activity of composite photocatalysts.展开更多
Heterojunction and morphology control assume a significant part in adjusting the intrinsic electromagnetic properties of absorbers to acquire outstanding microwave absorption(MA)performance,but this still faces huge c...Heterojunction and morphology control assume a significant part in adjusting the intrinsic electromagnetic properties of absorbers to acquire outstanding microwave absorption(MA)performance,but this still faces huge challenges.Herein,FeS_(2)/C/MoS_(2)composite with core–shell structure was successfully designed and prepared via a multi-interface engineering.MoS_(2)nanosheets with 1T and 2H phases are coated on the outside of FeS_(2)/C to form a porous interconnected structure that can optimize the impedance matching characteristics and strengthen the interfacial polarization loss capacity.Remarkably,as-fabricated FCM-3 harvests a broad effective absorption bandwidth(EAB)of 5.12 GHz and a minimum reflection loss(RL_(min))value of-45.1 d B.Meanwhile,FCM-3 can accomplish a greatest radar cross section(RCS)reduction value of 18.52 d B m^(2)when the detection angle is 0°.Thus,the convenient computer simulation technology(CST)simulations and encouraging accomplishments provide a novel avenue for the further development of efficient and lightweight MA materials.展开更多
Red phosphorus(RP)has been recognized as a promising anode candidate for sodium-ion batteries(SIBs)due to its high theor-etical capacity and natural abundance.However,the electrochemical performance of RP is restricte...Red phosphorus(RP)has been recognized as a promising anode candidate for sodium-ion batteries(SIBs)due to its high theor-etical capacity and natural abundance.However,the electrochemical performance of RP is restricted by the critical issues of the large volume variation upon cycling and the low intrinsic electronic conductivity.Herein,a nanocomposite with the structure of well-dispersed RP nanoparticles intimately attached to the surface of two-dimensional Ti_(3)C_(2) nanosheets(NRP/Ti_(3)C_(2))is prepared by a facile chemical precipitation method.The introduction of Ti_(3)C_(2) nanosheets can effectively prevent the RP nano-grains/clusters from agglomeration and growth in the synthesis process.Besides,the flexible Ti_(3)C_(2) sheets can not only function as the mechanical support for accommodating the volume change of RP upon Na+uptake/release process,but also provide an efficient conductive network for electron transportation.Moreover,the shortened ions diffusion distance enabled by the nano feature of RP further favors the electrode reaction kinetics.When employed as anode for SIBs,the synthesized NRP/Ti_(3)C_(2) composite exhibits a reversible capacity of~862 and 576 mAh·g^(-1) at 0.1 and 0.5 A·g^(-1),respectively,as well as a maintained capacity of 525.2 mAh·g^(-1) after 100 cycles at 0.1 A·g^(-1).In addition,the fabricated free-stand-ing NRP/Ti_(3)C_(2) electrode with a capacity of~2.21 mAh·cm-2 and stable electrochemical cycling provides a valid guide toward high-per-formance RP-based anodes for realizing SIBs with high energy density.展开更多
Metal–insulator–semiconductor(MOS) capacitor is a key structure for high performance MOS field transistors(MOSFETs), requiring low leakage current, high breakdown voltage, and low interface states. In this paper, β...Metal–insulator–semiconductor(MOS) capacitor is a key structure for high performance MOS field transistors(MOSFETs), requiring low leakage current, high breakdown voltage, and low interface states. In this paper, β-Ga_(2)O_(3) MOS capacitors were fabricated with ALD deposited Al_(2)O_(3) using H_(2)O or ozone(O_(3)) as precursors. Compared with the Al_(2)O_(3) gate dielectric with H_(2)O as ALD precursor, the leakage current for the O_(3) precursor case is decreased by two orders of magnitude, while it keeps the same level at the fixed charges, interface state density, and border traps. The SIMS tests show that Al_(2)O_(3) with O_(3) as precursor contains more carbon impurities. The current transport mechanism analysis suggests that the C–H complex in Al_(2)O_(3) with O_(3) precursor serves as deep energy trap to reduce the leakage current. These results indicate that the Al_(2)O_(3)/β-Ga_(2)O_(3)MOS capacitor using the O_(3) precursor has a low leakage current and holds potential for application in β-Ga_(2)O_(3) MOSFETs.展开更多
To separate the phosphorus-containing phase from steel slag,the effects of B_(2)O_(3)and Na_(2)B_(4)O_(7)on the enrichment of phosphorus-containing phases in Ca_(2)SiO_(4)–Ca_(3)(PO_(4))_(2)(C_(2)S–C_(3)P)solid solu...To separate the phosphorus-containing phase from steel slag,the effects of B_(2)O_(3)and Na_(2)B_(4)O_(7)on the enrichment of phosphorus-containing phases in Ca_(2)SiO_(4)–Ca_(3)(PO_(4))_(2)(C_(2)S–C_(3)P)solid solution were comparatively analyzed through theoretical calculations and experimental investigations.The results indicate that the optimum reaction temperature between B_(2)O_(3)and C_(2)S–C_(3)P is 800℃.The phase compositions of C_(2)S–C_(3)P equilibrium system with 5 wt.%B_(2)O_(3)at 800℃ included Ca_(3)(PO_(4))_(2),CaSiO_(3)and Ca11B_(2)Si_(4)O_(22),among which the content of Ca_(3)(PO_(4))_(2)was the highest.For C_(2)S–C_(3)P with 5 wt.%Na_(2)B_(4)O_(7)equilibrium system,Ca_(3)(PO_(4))_(2),CaSiO_(3),Ca11B_(2)Si_(4)O_(22)and Na_(2)Ca_(2)P_(2)O_(8)were independent at 390–690℃.Ca_(3)(PO_(4))_(2)and Ca_(2)SiO_(4)precipitated in the solid solution when the addition of B_(2)O_(3)was more than 6 wt.%,and the content of Ca_(3)(PO_(4))_(2)raised with the increase in the addition of B_(2)O_(3).The main phases in the C_(2)S–C_(3)P solid solution with Na_(2)B_(4)O_(7)were(Ca_(2)SiO_(4))0.05[Ca_(3)(PO_(4))_(2)],Ca_(2)SiO_(4)and Na_(3)Ca_(6)(PO_(4))_(5)at 650℃.And when the addition of Na_(2)B_(4)O_(7)exceeded 6 wt.%,the content of Na_(3)Ca_(6)(PO_(4))_(5)increased significantly.There was no precipitation of Ca_(3)(PO_(4))_(2)or boron-containing phase in the samples with Na_(2)B_(4)O_(7),but a small proportion of Ca_(3)(PO_(4))_(2)transformed into(Ca_(2)SiO_(4))0.05[Ca_(3)(PO_(4))_(2)],and Ca^(2+)was partially replaced by Na^(+)to generate Na_(3)Ca_(6)(PO_(4))_(5).As a result,the temperature for Na_(2)B_(4)O_(7)to enrich the phosphorus-containing phase in C_(2)S–C_(3)P solid solution was lower than that for B_(2)O_(3).However,the grade of the phosphorus-containing phase for Na_(2)B_(4)O_(7)was lower than that for B_(2)O_(3).展开更多
基于密度泛函理论的第一性原理方法,计算了Se掺杂单层MoS_2能带结构和光吸特性,并分析了对其光解水性质的影响。结果表明:本征单层MoS_2为直接带隙结构,禁带宽度为1.740 e V,导带底电位在H+/H2还原势之上0.430 e V,价带顶电位在O2/H2O...基于密度泛函理论的第一性原理方法,计算了Se掺杂单层MoS_2能带结构和光吸特性,并分析了对其光解水性质的影响。结果表明:本征单层MoS_2为直接带隙结构,禁带宽度为1.740 e V,导带底电位在H+/H2还原势之上0.430 e V,价带顶电位在O2/H2O的氧化势之下0.080 e V,具有可见光催化分解水的能力,但氧化和还原能力不均衡,导致单层MoS_2作为光催化剂分解水的效率不高。通过Se掺杂计算发现,单层MoS_2的禁带宽度变为1.727 e V,相应的光吸收谱变化幅度几乎不变,且体系的形成能较低,表明其热力学稳定性良好。然而,导带底电位调整到H+/H2还原势之上0.253 e V,价带顶电位处于O2/H2O的氧化势之下0.244e V,平衡了氧化与还原能力,单层MoS_2可见光催化分解水的效率得到提高。展开更多
文摘Van der Waals heterostructure, which consists of various two- dimensional （2D） layered materials stacked along the direction perpendicular to their 2D plane, has emerged as a promising material system for device applications in recent years .
文摘Although bimetallic phosphide cocatalysts have attracted considerable interest in photocatalysis research owing to their advantageous thermodynamic characteristics,superstable and efficient cocatalysts have rarely been produced through the modulation of their structure and composition.In this study,a series of bimetallic nickel-iron phosphide(Ni_(x)Fe_(2-x)P,where 0<x<2)cocatalysts with controllable structures and overpotentials were designed by adjusting the atomic ratio of Ni/Fe onto nonmetallic elemental red phosphorus(RP)for the photocatalytic selective oxidation of benzyl alcohol(BA)coupled with hydrogen production.The catalysts exhibited an outstanding photocatalytic activity for benzaldehyde and a high H_(2)yield.The RP regulated by bimetallic phosphide cocatalysts(Ni_(x)Fe_(2-x)P)demonstrated higher photocatalytic oxidation-reduction activity than that regulated by monometallic phosphide cocatalysts(Ni_(2)P and Fe2P).In particular,the RP regulated by Ni_(1.25)Fe_(0.75)P exhibited the best photocatalytic performance.In addition,experimental and theoretical calculations further illustrated that Ni_(1.25)Fe_(0.75)P,with the optimized electronic structure,possessed good electrical conductivity and provided strong adsorption and abundant active sites,thereby accelerating electron migration and lowering the reaction energy barrier of RP.This finding offers valuable insights into the rational design of highly effective cocatalysts aimed at optimizing the photocatalytic activity of composite photocatalysts.
基金financially supported by the National Natural Science Foundation of China(Nos.52402354,62174016 and 12374394)China Postdoctoral Science Foundation(Nos.2023M740471)the Natural Science Foundation of Jiangsu Higher Education Institutions(Nos.24KJB430002)。
文摘Heterojunction and morphology control assume a significant part in adjusting the intrinsic electromagnetic properties of absorbers to acquire outstanding microwave absorption(MA)performance,but this still faces huge challenges.Herein,FeS_(2)/C/MoS_(2)composite with core–shell structure was successfully designed and prepared via a multi-interface engineering.MoS_(2)nanosheets with 1T and 2H phases are coated on the outside of FeS_(2)/C to form a porous interconnected structure that can optimize the impedance matching characteristics and strengthen the interfacial polarization loss capacity.Remarkably,as-fabricated FCM-3 harvests a broad effective absorption bandwidth(EAB)of 5.12 GHz and a minimum reflection loss(RL_(min))value of-45.1 d B.Meanwhile,FCM-3 can accomplish a greatest radar cross section(RCS)reduction value of 18.52 d B m^(2)when the detection angle is 0°.Thus,the convenient computer simulation technology(CST)simulations and encouraging accomplishments provide a novel avenue for the further development of efficient and lightweight MA materials.
基金supported by the National Natural Science Foundation of China(No.U23B20171)the National Key R&D Program of China(Nos.2023YFE0119500 and 2024YFB2408303).
文摘Red phosphorus(RP)has been recognized as a promising anode candidate for sodium-ion batteries(SIBs)due to its high theor-etical capacity and natural abundance.However,the electrochemical performance of RP is restricted by the critical issues of the large volume variation upon cycling and the low intrinsic electronic conductivity.Herein,a nanocomposite with the structure of well-dispersed RP nanoparticles intimately attached to the surface of two-dimensional Ti_(3)C_(2) nanosheets(NRP/Ti_(3)C_(2))is prepared by a facile chemical precipitation method.The introduction of Ti_(3)C_(2) nanosheets can effectively prevent the RP nano-grains/clusters from agglomeration and growth in the synthesis process.Besides,the flexible Ti_(3)C_(2) sheets can not only function as the mechanical support for accommodating the volume change of RP upon Na+uptake/release process,but also provide an efficient conductive network for electron transportation.Moreover,the shortened ions diffusion distance enabled by the nano feature of RP further favors the electrode reaction kinetics.When employed as anode for SIBs,the synthesized NRP/Ti_(3)C_(2) composite exhibits a reversible capacity of~862 and 576 mAh·g^(-1) at 0.1 and 0.5 A·g^(-1),respectively,as well as a maintained capacity of 525.2 mAh·g^(-1) after 100 cycles at 0.1 A·g^(-1).In addition,the fabricated free-stand-ing NRP/Ti_(3)C_(2) electrode with a capacity of~2.21 mAh·cm-2 and stable electrochemical cycling provides a valid guide toward high-per-formance RP-based anodes for realizing SIBs with high energy density.
基金Project supported in part by the Science and Technology Development Plan Project of Jilin Province, China (Grant No. YDZJ202303CGZH022)the National Key Research and Development Program of China (Grant No. 2024YFE0205300)+1 种基金the National Natural Science Foundation of China (Grant No. 62471504)the Open Fund of the State Key Laboratory of Optoelectronic Materials and Technologies (Sun Yat-Sen University) (Grant No. OEMT-2023KF-05)。
文摘Metal–insulator–semiconductor(MOS) capacitor is a key structure for high performance MOS field transistors(MOSFETs), requiring low leakage current, high breakdown voltage, and low interface states. In this paper, β-Ga_(2)O_(3) MOS capacitors were fabricated with ALD deposited Al_(2)O_(3) using H_(2)O or ozone(O_(3)) as precursors. Compared with the Al_(2)O_(3) gate dielectric with H_(2)O as ALD precursor, the leakage current for the O_(3) precursor case is decreased by two orders of magnitude, while it keeps the same level at the fixed charges, interface state density, and border traps. The SIMS tests show that Al_(2)O_(3) with O_(3) as precursor contains more carbon impurities. The current transport mechanism analysis suggests that the C–H complex in Al_(2)O_(3) with O_(3) precursor serves as deep energy trap to reduce the leakage current. These results indicate that the Al_(2)O_(3)/β-Ga_(2)O_(3)MOS capacitor using the O_(3) precursor has a low leakage current and holds potential for application in β-Ga_(2)O_(3) MOSFETs.
基金funding support from the National Key R&D Program of China(2020YFC1909105)the 2023 Basic Research Foundation Project for Universities in the Inner Mongolia Autonomous Region(2023RCTD006)+1 种基金the Major Science and Technology Project of Inner Mongolia Autonomous Region(2021ZD0016)the National Natural Science Foundation of China(51664044).
文摘To separate the phosphorus-containing phase from steel slag,the effects of B_(2)O_(3)and Na_(2)B_(4)O_(7)on the enrichment of phosphorus-containing phases in Ca_(2)SiO_(4)–Ca_(3)(PO_(4))_(2)(C_(2)S–C_(3)P)solid solution were comparatively analyzed through theoretical calculations and experimental investigations.The results indicate that the optimum reaction temperature between B_(2)O_(3)and C_(2)S–C_(3)P is 800℃.The phase compositions of C_(2)S–C_(3)P equilibrium system with 5 wt.%B_(2)O_(3)at 800℃ included Ca_(3)(PO_(4))_(2),CaSiO_(3)and Ca11B_(2)Si_(4)O_(22),among which the content of Ca_(3)(PO_(4))_(2)was the highest.For C_(2)S–C_(3)P with 5 wt.%Na_(2)B_(4)O_(7)equilibrium system,Ca_(3)(PO_(4))_(2),CaSiO_(3),Ca11B_(2)Si_(4)O_(22)and Na_(2)Ca_(2)P_(2)O_(8)were independent at 390–690℃.Ca_(3)(PO_(4))_(2)and Ca_(2)SiO_(4)precipitated in the solid solution when the addition of B_(2)O_(3)was more than 6 wt.%,and the content of Ca_(3)(PO_(4))_(2)raised with the increase in the addition of B_(2)O_(3).The main phases in the C_(2)S–C_(3)P solid solution with Na_(2)B_(4)O_(7)were(Ca_(2)SiO_(4))0.05[Ca_(3)(PO_(4))_(2)],Ca_(2)SiO_(4)and Na_(3)Ca_(6)(PO_(4))_(5)at 650℃.And when the addition of Na_(2)B_(4)O_(7)exceeded 6 wt.%,the content of Na_(3)Ca_(6)(PO_(4))_(5)increased significantly.There was no precipitation of Ca_(3)(PO_(4))_(2)or boron-containing phase in the samples with Na_(2)B_(4)O_(7),but a small proportion of Ca_(3)(PO_(4))_(2)transformed into(Ca_(2)SiO_(4))0.05[Ca_(3)(PO_(4))_(2)],and Ca^(2+)was partially replaced by Na^(+)to generate Na_(3)Ca_(6)(PO_(4))_(5).As a result,the temperature for Na_(2)B_(4)O_(7)to enrich the phosphorus-containing phase in C_(2)S–C_(3)P solid solution was lower than that for B_(2)O_(3).However,the grade of the phosphorus-containing phase for Na_(2)B_(4)O_(7)was lower than that for B_(2)O_(3).
文摘基于密度泛函理论的第一性原理方法,计算了Se掺杂单层MoS_2能带结构和光吸特性,并分析了对其光解水性质的影响。结果表明:本征单层MoS_2为直接带隙结构,禁带宽度为1.740 e V,导带底电位在H+/H2还原势之上0.430 e V,价带顶电位在O2/H2O的氧化势之下0.080 e V,具有可见光催化分解水的能力,但氧化和还原能力不均衡,导致单层MoS_2作为光催化剂分解水的效率不高。通过Se掺杂计算发现,单层MoS_2的禁带宽度变为1.727 e V,相应的光吸收谱变化幅度几乎不变,且体系的形成能较低,表明其热力学稳定性良好。然而,导带底电位调整到H+/H2还原势之上0.253 e V,价带顶电位处于O2/H2O的氧化势之下0.244e V,平衡了氧化与还原能力,单层MoS_2可见光催化分解水的效率得到提高。
