This paper discusses the influence of Sb/In ratio on the transport properties and crystal quality of the 200 nm InAs_(x)Sb_(1-x)thin film.The Sb content of InAs_(x)Sb_(1-x)thin film in all samples was verified by HRXR...This paper discusses the influence of Sb/In ratio on the transport properties and crystal quality of the 200 nm InAs_(x)Sb_(1-x)thin film.The Sb content of InAs_(x)Sb_(1-x)thin film in all samples was verified by HRXRD of the symmetrical 004 reflections and asymmetrical 115 reflections.The calculation results show that the Sb component was 0.6 in the InAs_(x)Sb_(1-x)thin film grown under the conditions of Sb/In ratio of 6 and As/In ratio of 3,which has the highest electron mobility(28560 cm^(2)/V·s)at 300 K.At the same time,the influence ofⅤ/Ⅲratio on the transport properties and crystal quality of Al_(0.2)In_(0.8)Sb/InAs_(x)Sb_(1-x)quantum well heterostructures also has been investigated.As a result,the Al_(0.2)In_(0.8)Sb/InAs_(0.4)Sb_(0.6)quantum well heterostructure with a channel thickness of 30 nm grown under the conditions of Sb/In ratio of 6 and As/In ratio of 3 has a maximum electron mobility of 28300 cm^(2)/V·s and a minimum RMS roughness of 0.68 nm.Through optimizing the growth conditions,our samples have higher electron mobility and smoother surface morphology.展开更多
The difficulty in fabricating a multifaceted composite heterojunction system based on Cd_(x) Zn_(1-x) S limits the enhancement of photocatalytic performance.In the present scrutiny,novel ZnO/Cd_(x) Zn_(1-x) S/CdS com-...The difficulty in fabricating a multifaceted composite heterojunction system based on Cd_(x) Zn_(1-x) S limits the enhancement of photocatalytic performance.In the present scrutiny,novel ZnO/Cd_(x) Zn_(1-x) S/CdS com-posite heterojunctions are successfully prepared by the alkaline dissolution etching method.The internal electric field at the interface of I-type and Z-scheme heterojunction improved the effective charge sepa-ration.The ZC 8 sample exhibits excellent photocatalytic performance and the H2 production efficiency is 15.67 mmol g^(−1) h^(−1) with good stability up to 82.9%in 24-hour cycles.The performance of CH_(4) and CO capacity in the CO_(2) RR process is 3.47μmol g^(−1) h^(−1) and 23.5μmol g^(−1) h^(−1),respectively.The photogener-ated accelerated charge transport is then examined in detail by in situ X-ray photoelectron spectroscopy(ISXPS)and density functional theory(DFT)calculations.This work presents a new idea for the synthe-sis of Cd_(x) Zn_(1-x) S solid-solution-based materials and provides a solid reference for the detailed mechanism regarding the electric field at the heterojunction interface.展开更多
Dry reforming of methane(DRM)has gained significant attention as a promising route to convert two major greenhouse gases(CO_(2) and CH4)to syngas.The development of efficient catalysts is critical for the engineering ...Dry reforming of methane(DRM)has gained significant attention as a promising route to convert two major greenhouse gases(CO_(2) and CH4)to syngas.The development of efficient catalysts is critical for the engineering applications.In this study,the Ce_(x)Zr_(1-x)O_(2)/ZSM-5 composites with different oxygen vacancy concentrations were synthesized by tuning the Ce/Zr ratio,followed by the deposition of metal Ni to island-like Ce_(x)Zr_(1-x)O_(2)on ZSM-5,forming a variety of Ni-Ce_(x)Zr_(1-x)O_(2)/ZSM-5 catalysts,which were applied for the DRM reaction under 750◦C.Combined with various characterizations,it was found that the oxygen vacancy concentration illustrated the volcanic tendency with the decreased Ce/Zr ratio,and the interaction between metal Ni and Ce_(x)Zr_(1-x)O_(2)exhibited a positive relationship with oxygen vacancy concentration.The enhanced between Ni and Ce_(x)Zr_(1-x)O_(2)interaction could improve the strength and amount of Ni-O-M(M=Ce/Zr)species,making the d-band centers of catalysts closer to the Fermi energy level,which was beneficial to the CH4 and CO_(2) activation,along with the improved capacity to resist sintering and coking.Especially,the C1Z3(Ni-Ce0.25Zr0.75O_(2)/ZSM-5)catalyst with the Ce/Zr ratio of 1/3 demonstrated the optimal catalytic performance with 91.9%CH4 and 93.8%CO_(2) conversions within 50 h,accompanied by the best structural and catalytic stability after 100 h.In-situ DRIFTS was employed to study the reaction path and mechanism,discovering that significant amounts of strengthened Ni-O-M species were conducive to activating adsorbed CH4 and CO_(2),and desorbing the linear CO species.展开更多
Most studies have shown that oxygen vacancies on Ce_(x)Zr_(1-x)O_(2) solid solution are important for enhancing the catalytic oxidation performance.However,a handful of studies investigated the different roles of surf...Most studies have shown that oxygen vacancies on Ce_(x)Zr_(1-x)O_(2) solid solution are important for enhancing the catalytic oxidation performance.However,a handful of studies investigated the different roles of surface and subsurface oxygen vacancies on the performance and mechanisms of catalysts.Herein,a series of zirconium doping on CeO_(2) samples(CeO_(2),Ce_(0.95)Zr_(0.05)O_(2),and Ce_(0.8)5Zr_(0.15)O_(2))with various surface-to-subsurface oxygen vacancies ratios have been synthesized and applied in toluene catalytic oxidation.The obtained Ce_(0.95)Zr_(0.05)O_(2) exhibits an excellent catalytic performance with a 90%toluene conversion at 295℃,which is 68℃lower than that of CeO_(2).Additionally,the obtained Ce_(0.95)Zr_(0.05)O_(2)catalyst also exhibited good catalytic stability and water resistance.The XRD and HRTEM results show that Zr ions are incorporated into CeO_(2) lattice,forming Ce_(x)Zr_(1-x)O_(2) solid solution.Temperature-programmed experiments reveal that Ce_(0.95)Zr_(0.05)O_(2) shows excellent lowtemperature reducibility and abundant surface oxygen species.In-situ DRIFTS tests were used to probe the reaction mechanism,and the function of Zr doping in promoting the activation of oxygen was further determined.Density functional theory(DFT)calculations indicate that the vacancy formation energy and O_(2) adsorption energy are both lower on Ce_(0.95)Zr_(0.05)O_(2),confirming the reason for its superior catalytic performance.展开更多
Lithium nickel oxide(Li_(2)NiO_(2)),as a sacrificial cathode prelithiation additive,has been used to compensate for the lithium loss for improving the lifespan of lithium-ion batteries(LIBs).However,high-cost Li_(2)Ni...Lithium nickel oxide(Li_(2)NiO_(2)),as a sacrificial cathode prelithiation additive,has been used to compensate for the lithium loss for improving the lifespan of lithium-ion batteries(LIBs).However,high-cost Li_(2)NiO_(2)suffers from inferior delithiation kinetics during the first cycle.Herein,we investigated the effects of the cost-effective copper substituted Li_(2)Ni_(1-x)Cu_(x)O_(2)(x=0,0.2,0.3,0.5,0.7)synthesized by a high-temperature solid-phase method on the structure,morphology,electrochemical performance of graphite‖LiFePO_(4)battery.The X-ray diffraction(XRD)refinement result demonstrated that Cu substitution strategy could be favorable for eliminating the NiO_(x)impurity phase and weakening Li-O bond.Analysis on density of states(DOS)indicates that Cu substitution is good for enhancing the electronic conductivity,as well as reducing the delithi-ation voltage polarization confirmed by electrochemical characterizations.Therefore,the optimal Li_(2)Ni_(0.7)Cu_(0.3)O_(2)delivered a high delithiation capacity of 437 mAh·g^(-1),around 8%above that of the pristine Li_(2)NiO_(2).Furthermore,a graphite‖LiFePO_(4)pouch cell with a nominal capacity of 3000 mAh demonstrated a notably improved reversible capacity,energy density and cycle life through introducing 2 wt%Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive,delivering a 6.2 mAh·g^(-1)higher initial discharge capacity and achieving around 5%improvement in capacity retentnion at 0.5P over 1000 cycles.Additionally,the post-mortem analyses testified that the Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive could suppress solid electrolyte interphase(SEI)decomposition and homogenize the Li distribution,which benefits to stabilizing interface between graphite and electrolyte,and alleviating dendritic Li plating.In conclusion,the Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive may offer advantages such as lower cost,lower delithiation voltage and higher prelithiation capacity compared with Li_(2)NiO_(2),making it a promising candidate of cathode prelithiation additive for next-generation LIBs.展开更多
基金Supported by the Natural Science Basic Research Program of Shaanxi Province(2023-JC-QN-0758)Shaanxi University of Science and Technology Research Launch Project(2020BJ-26)Doctoral Research Initializing Fund of Hebei University of Science and Technology,China(1181476).
文摘This paper discusses the influence of Sb/In ratio on the transport properties and crystal quality of the 200 nm InAs_(x)Sb_(1-x)thin film.The Sb content of InAs_(x)Sb_(1-x)thin film in all samples was verified by HRXRD of the symmetrical 004 reflections and asymmetrical 115 reflections.The calculation results show that the Sb component was 0.6 in the InAs_(x)Sb_(1-x)thin film grown under the conditions of Sb/In ratio of 6 and As/In ratio of 3,which has the highest electron mobility(28560 cm^(2)/V·s)at 300 K.At the same time,the influence ofⅤ/Ⅲratio on the transport properties and crystal quality of Al_(0.2)In_(0.8)Sb/InAs_(x)Sb_(1-x)quantum well heterostructures also has been investigated.As a result,the Al_(0.2)In_(0.8)Sb/InAs_(0.4)Sb_(0.6)quantum well heterostructure with a channel thickness of 30 nm grown under the conditions of Sb/In ratio of 6 and As/In ratio of 3 has a maximum electron mobility of 28300 cm^(2)/V·s and a minimum RMS roughness of 0.68 nm.Through optimizing the growth conditions,our samples have higher electron mobility and smoother surface morphology.
基金financially supported by the National Key Re-search and Development Program of China[No.2022YFF1202500,2022YFF1202502]the National Natural Science Foundation of China[62071459]+1 种基金the Subject arrangement Foundation of Shen-zhen[No.JCYJ20180507182057026]the International Science and Technology Cooperation Project of Bingtuan[No.2022BC008]。
文摘The difficulty in fabricating a multifaceted composite heterojunction system based on Cd_(x) Zn_(1-x) S limits the enhancement of photocatalytic performance.In the present scrutiny,novel ZnO/Cd_(x) Zn_(1-x) S/CdS com-posite heterojunctions are successfully prepared by the alkaline dissolution etching method.The internal electric field at the interface of I-type and Z-scheme heterojunction improved the effective charge sepa-ration.The ZC 8 sample exhibits excellent photocatalytic performance and the H2 production efficiency is 15.67 mmol g^(−1) h^(−1) with good stability up to 82.9%in 24-hour cycles.The performance of CH_(4) and CO capacity in the CO_(2) RR process is 3.47μmol g^(−1) h^(−1) and 23.5μmol g^(−1) h^(−1),respectively.The photogener-ated accelerated charge transport is then examined in detail by in situ X-ray photoelectron spectroscopy(ISXPS)and density functional theory(DFT)calculations.This work presents a new idea for the synthe-sis of Cd_(x) Zn_(1-x) S solid-solution-based materials and provides a solid reference for the detailed mechanism regarding the electric field at the heterojunction interface.
基金the following financial supports:National Natural Science Foundation of China(22075225 and 22038011)Innovative Scientific Program of CNNC,State Key Laboratory of Clean and Efficient Coal Utilization,Taiyuan University of Technology(MJNYSKL202401,MJNYSKL202404).
文摘Dry reforming of methane(DRM)has gained significant attention as a promising route to convert two major greenhouse gases(CO_(2) and CH4)to syngas.The development of efficient catalysts is critical for the engineering applications.In this study,the Ce_(x)Zr_(1-x)O_(2)/ZSM-5 composites with different oxygen vacancy concentrations were synthesized by tuning the Ce/Zr ratio,followed by the deposition of metal Ni to island-like Ce_(x)Zr_(1-x)O_(2)on ZSM-5,forming a variety of Ni-Ce_(x)Zr_(1-x)O_(2)/ZSM-5 catalysts,which were applied for the DRM reaction under 750◦C.Combined with various characterizations,it was found that the oxygen vacancy concentration illustrated the volcanic tendency with the decreased Ce/Zr ratio,and the interaction between metal Ni and Ce_(x)Zr_(1-x)O_(2)exhibited a positive relationship with oxygen vacancy concentration.The enhanced between Ni and Ce_(x)Zr_(1-x)O_(2)interaction could improve the strength and amount of Ni-O-M(M=Ce/Zr)species,making the d-band centers of catalysts closer to the Fermi energy level,which was beneficial to the CH4 and CO_(2) activation,along with the improved capacity to resist sintering and coking.Especially,the C1Z3(Ni-Ce0.25Zr0.75O_(2)/ZSM-5)catalyst with the Ce/Zr ratio of 1/3 demonstrated the optimal catalytic performance with 91.9%CH4 and 93.8%CO_(2) conversions within 50 h,accompanied by the best structural and catalytic stability after 100 h.In-situ DRIFTS was employed to study the reaction path and mechanism,discovering that significant amounts of strengthened Ni-O-M species were conducive to activating adsorbed CH4 and CO_(2),and desorbing the linear CO species.
基金supported by the National Natural Science Foundation(No.51678291)the Basic Science(Natural Science)Research in Higher Education in Jiangsu Province(No.23KJA610003)the High-level Scientific Research Foundation for the introduction of talent in Nanjing Institute of Technology(No.YKJ201999)。
文摘Most studies have shown that oxygen vacancies on Ce_(x)Zr_(1-x)O_(2) solid solution are important for enhancing the catalytic oxidation performance.However,a handful of studies investigated the different roles of surface and subsurface oxygen vacancies on the performance and mechanisms of catalysts.Herein,a series of zirconium doping on CeO_(2) samples(CeO_(2),Ce_(0.95)Zr_(0.05)O_(2),and Ce_(0.8)5Zr_(0.15)O_(2))with various surface-to-subsurface oxygen vacancies ratios have been synthesized and applied in toluene catalytic oxidation.The obtained Ce_(0.95)Zr_(0.05)O_(2) exhibits an excellent catalytic performance with a 90%toluene conversion at 295℃,which is 68℃lower than that of CeO_(2).Additionally,the obtained Ce_(0.95)Zr_(0.05)O_(2)catalyst also exhibited good catalytic stability and water resistance.The XRD and HRTEM results show that Zr ions are incorporated into CeO_(2) lattice,forming Ce_(x)Zr_(1-x)O_(2) solid solution.Temperature-programmed experiments reveal that Ce_(0.95)Zr_(0.05)O_(2) shows excellent lowtemperature reducibility and abundant surface oxygen species.In-situ DRIFTS tests were used to probe the reaction mechanism,and the function of Zr doping in promoting the activation of oxygen was further determined.Density functional theory(DFT)calculations indicate that the vacancy formation energy and O_(2) adsorption energy are both lower on Ce_(0.95)Zr_(0.05)O_(2),confirming the reason for its superior catalytic performance.
基金supported by the Significant Science and Technology Project in Xiamen(Future Industry Field)(Grant No.3502Z20231057).
文摘Lithium nickel oxide(Li_(2)NiO_(2)),as a sacrificial cathode prelithiation additive,has been used to compensate for the lithium loss for improving the lifespan of lithium-ion batteries(LIBs).However,high-cost Li_(2)NiO_(2)suffers from inferior delithiation kinetics during the first cycle.Herein,we investigated the effects of the cost-effective copper substituted Li_(2)Ni_(1-x)Cu_(x)O_(2)(x=0,0.2,0.3,0.5,0.7)synthesized by a high-temperature solid-phase method on the structure,morphology,electrochemical performance of graphite‖LiFePO_(4)battery.The X-ray diffraction(XRD)refinement result demonstrated that Cu substitution strategy could be favorable for eliminating the NiO_(x)impurity phase and weakening Li-O bond.Analysis on density of states(DOS)indicates that Cu substitution is good for enhancing the electronic conductivity,as well as reducing the delithi-ation voltage polarization confirmed by electrochemical characterizations.Therefore,the optimal Li_(2)Ni_(0.7)Cu_(0.3)O_(2)delivered a high delithiation capacity of 437 mAh·g^(-1),around 8%above that of the pristine Li_(2)NiO_(2).Furthermore,a graphite‖LiFePO_(4)pouch cell with a nominal capacity of 3000 mAh demonstrated a notably improved reversible capacity,energy density and cycle life through introducing 2 wt%Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive,delivering a 6.2 mAh·g^(-1)higher initial discharge capacity and achieving around 5%improvement in capacity retentnion at 0.5P over 1000 cycles.Additionally,the post-mortem analyses testified that the Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive could suppress solid electrolyte interphase(SEI)decomposition and homogenize the Li distribution,which benefits to stabilizing interface between graphite and electrolyte,and alleviating dendritic Li plating.In conclusion,the Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive may offer advantages such as lower cost,lower delithiation voltage and higher prelithiation capacity compared with Li_(2)NiO_(2),making it a promising candidate of cathode prelithiation additive for next-generation LIBs.
