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The structure-directing role of heterologous seeds in the synthesis of zeolite 被引量:2
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作者 Haoyang Zhang Binyu Wang Wenfu Yan 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第5期792-801,共10页
Zeolites have been widely used as catalysts,ion-exchangers,and adsorbents in chemical industries,detergent industry,steel industry,glass industry,ceramic industry,medical and healthfield,and environmentalfield,and recen... Zeolites have been widely used as catalysts,ion-exchangers,and adsorbents in chemical industries,detergent industry,steel industry,glass industry,ceramic industry,medical and healthfield,and environmentalfield,and recently applied in energy storage.Seed-assisted synthesis is a very effective approach in promoting the crystallization of zeolites.In some cases,the target zeolite cannot be formed in the absence of seed zeolite.In homologous seed-assisted synthesis,the structure of the seed zeolite is the same to that of the target zeolite,while the structure of the seed zeolite is different to that of the target zeolite in the heterologous seed-assisted synthesis.In this review,we briefly summarized the heterologous seed-assisted syntheses of zeolites and analyzed the structure-directing effect of heterologous seeds and surveyed the“common composite building units(CBUs)hypothesis”and the“common secondary building units(SBUs)hypothesis”.However,both hypotheses cannot explain all observations on the heterologous seed-assisted syntheses.Finally,we proposed that the formation of the target zeolite does need nuclei with the structure of target zeolite and the formation of the nuclei of the target zeolite can be promoted by either the undissolved seed crystals with the same CBUs or SBUs to the target zeolite or by the facilitated appropriate distribution of the specific building units due to the presence of the heterologous seed that does not have any common CBUs and SBUs with the target zeolite. 展开更多
关键词 ZEOLITE Heterologous seed SYNTHESIS Structure-directing effect
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Potential industrial applications of photo/electrocatalysis: Recent progress and future challenges 被引量:2
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作者 Jinhao Li Jing Ren +8 位作者 Shaoquan Li Guangchao Li Molly Meng-Jung Li Rengui Li Young Soo Kang Xiaoxin Zou Yong Luo Bin Liu Yufei Zhao 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第5期859-876,共18页
Nowadays,the rapid development of the social economy inevitably leads to global energy and environmental crisis.For this reason,more and more scholars focus on the development of photocatalysis and/or electrocatalysis... Nowadays,the rapid development of the social economy inevitably leads to global energy and environmental crisis.For this reason,more and more scholars focus on the development of photocatalysis and/or electrocatalysis technology for the advantage in the sustainable production of high-value-added products,and the high efficiency in pollutants remediation.Although there is plenty of outstanding research has been put forward continuously,most of them focuses on catalysis performance and reaction mechanisms in laboratory conditions.Realizing industrial application of photo/electrocatalytic processes is still a challenge that needs to be overcome by social demand.In this regard,this review comprehensively summarized several explorations in thefield of photo/electrocatalytic reduction towards potential industrial applications in recent years.Special attention is paid to the successful attempts and the current status of photo/electrocatalytic water splitting,carbon dioxide conversion,resource utilization from waste,etc.,by using advanced reactors.The key problems and challenges of photo/electrocatalysis in future industrial practice are also discussed,and the possible development directions are also pointed out from the industry view. 展开更多
关键词 PHOTOCATALYSIS ELECTROCATALYSIS Industrial applications H2 economy
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Electrochemical synthesis of trimetallic nickel-iron-copper nanoparticles via potential-cycling for high current density anion exchange membrane water-splitting applications
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作者 Ziqi Zhang Sheng Wan +4 位作者 Hanbo Wang Jinghan He Ruige Zhang Yuhang Qi Haiyan Lu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第2期535-542,I0012,共9页
Hydrogen is known for its elevated energy density and environmental compatibility and is a promising alternative to fossil fuels.Alkaline water electrolysis utilizing renewable energy sources has emerged as a means to... Hydrogen is known for its elevated energy density and environmental compatibility and is a promising alternative to fossil fuels.Alkaline water electrolysis utilizing renewable energy sources has emerged as a means to obtain high-purity hydrogen.Nevertheless,electrocatalysts used in the process are fabricated using conventional wet chemical synthesis methods,such as sol-gel,hydrothermal,or surfactantassisted approaches,which often necessitate intricate pretreatment procedures and are vulnerable to post-treatment contamination.Therefore,this study introduces a streamlined and environmentally conscious one-step potential-cycling approach to generate a highly efficient trimetallic nickel-iron-copper electrocatalyst in situ on nickel foam.The synthesized material exhibited remarkable performance,requiring a mere 476 mV to drive electrochemical water splitting at 100 mA cm^(-2)current density in alkaline solution.Furthermore,this material was integrated into an anion exchange membrane watersplitting device and achieved an exceptionally high current density of 1 A cm^(-2)at a low cell voltage of2.13 V,outperforming the noble-metal benchmark(2.51 V).Additionally,ex situ characterizations were employed to detect transformations in the active sites during the catalytic process,revealing the structural transformations and providing inspiration for further design of electrocatalysts. 展开更多
关键词 Electrocatalytic water splitting Hydrogen evolution reaction Oxygen evolution reaction Electrochemical synthesis Anion exchange membrane
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Rational design of new in situ reduction of Ni(II)catalytic system for low-cost and large-scale preparation of porous aromatic frameworks
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作者 Shanshan Wang Yue Wu +3 位作者 Wenxiang Zhang Hao Ren Guangshan Zhu Heping Ma 《Carbon Energy》 SCIE EI CAS CSCD 2024年第5期105-113,共9页
Porous aromatic framework 1(PAF-1)is an extremely representative nanoporous organic framework owing to its high stability and exceptionally high surface area.Currently,the synthesis of PAF-1 is catalyzed by the Ni(COD... Porous aromatic framework 1(PAF-1)is an extremely representative nanoporous organic framework owing to its high stability and exceptionally high surface area.Currently,the synthesis of PAF-1 is catalyzed by the Ni(COD)2/COD/bpy system,suffering from great instability and high cost.Herein,we developed an in situ reduction of the Ni(II)catalytic system to synthesize PAF-1 in low cost and high yield.The active Ni(0)species produced from the NiCl_(2)/bpy/NaI/Mg catalyst system can effectively catalyze homocoupling of tetrakis(4-bromophenyl)methane at the room temperature to form PAF-1 with high Brunauer-Emmett-Teller(BET)-specific surface area up to 4948 m^(2) g^(−1)(Langmuir surface area,6785 m2 g−1).The possible halogen exchange and dehalogenation coupling mechanisms for this new catalytic process in PAF's synthesis are discussed in detail.The efficiency and universality of this innovative catalyst system have also been demonstrated in other PAFs'synthesis.This work provides a cheap,facile,and efficient method for scalable synthesis of PAFs and explores their application for high-pressure storage of Xe and Kr. 展开更多
关键词 adsorption carbon material nickel catalysis porous aromatic framework porous organic polymer
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A Single-chain Antibody for One-pot Fabrication of Luminescent Gold Nanoclusters and Rabies Virus Imaging in Cells
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作者 ZHANG Chunxia XI Hualong +4 位作者 SUN Bo WU Yongge JIANG Chunlai YU Xianghui WU Yuqing 《发光学报》 EI CAS CSCD 北大核心 2024年第10期1732-1740,共9页
The fragile antibody leads to a great challenge as a scaffold to fabricate the luminescent metal nanoclusters using one-pot method.This study presents a stable single-chain anti-body(scFv57R-ATS)for the fabrication of... The fragile antibody leads to a great challenge as a scaffold to fabricate the luminescent metal nanoclusters using one-pot method.This study presents a stable single-chain anti-body(scFv57R-ATS)for the fabrication of luminescent gold nanoclusters(AuNCs@scFv57R-ATS)and a quick,sensitive rabies virus detection in living cells.In this paper,AuNCs@scFv57R-ATS was designed to specifically recognize antigen RV in modified HeLa cells,which promoted the demonstration of metal nanocluster fluorescent probes for antigen targeting and therapy. 展开更多
关键词 gold nanoclusters scFv57R-ATS rabies virus
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Understanding Bonding Nature of α-Keggin Polyoxometalates[XW_(12)O_(40)]^(n−)(X=Al,Si,P,S):A Generalized Superatomic Perspective
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作者 Rui Li Yulei Shi +4 位作者 Famin Yu Rui Wang Haitao Yan Boon K.Teo Zhigang Wang 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第6期176-183,共8页
α-Keggin polyoxometalates(POMs)[XW_(12)O_(40)]^(n−)(X=Al,Si,P,S)are widely used in batteries owing to their remarkable redox activity.However,the mechanism underlying the applications appears inconsistent with the wi... α-Keggin polyoxometalates(POMs)[XW_(12)O_(40)]^(n−)(X=Al,Si,P,S)are widely used in batteries owing to their remarkable redox activity.However,the mechanism underlying the applications appears inconsistent with the widely accepted covalent bonding nature.Here,first-principles calculations show that XW_(12)are core–shell structures composed of a shell and an XO_(4)^(n−)core,both are stabilized by covalent interactions.Interestingly,owing to the presence of a substantial number of electrons in W_(12)O_(36)shell,the frontier molecular orbitals of XW_(12)are not only strongly delocalized but also exhibit superatomic properties with high-angular momentum electrons that do not conform to the Jellium model.Detailed analysis indicates that energetically high lying filled molecular orbitals(MOs)have reached unusually high-angular momentum characterized by quantum number K or higher,allowing for the accommodation of numerous electrons.This attribute confers strong electron acceptor ability and redox activity to XW_(12).Moreover,electrons added to XW_(12)still occupy the K orbitals and will not cause rearrangement of the MOs,thereby maintaining the stability of these structures.Our findings highlight the structure–activity relationship and provide a direction for tailor-made POMs with specific properties at atomic level. 展开更多
关键词 first principles molecular orbital POLYOXOMETALATE redox activity superatom
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Electrochemistry of Hydroquinone Derivatives at Metal and Iodine-modified Metal Electrodes 被引量:1
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作者 HOU Peng HAN Dong-xue +1 位作者 NIU Li LIN Hai-bo 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2006年第4期493-499,共7页
The difference in the electrochemical behavior of hydroquinone and pyrocatechol at platinum and gold surfaces was analyzed using voltammetry and attenuated total reflection Fourier transform infrared spectroscopy. The... The difference in the electrochemical behavior of hydroquinone and pyrocatechol at platinum and gold surfaces was analyzed using voltammetry and attenuated total reflection Fourier transform infrared spectroscopy. The results show that the hydroquinone derivatives are adsorbed on a gold surface with vertical orientation, which makes the electron transfer between the bulk species and the electrode surface easier than that in the case of flat adsorption of hydroquinone derivatives that occurs at a platinum electrode. The formation of the vertical conformation and the rapid process of electron transfer were also confirmed by quantum chemistry calculations. In addition, the pre-adsorbed iodine on the electrodes played a key role on the adsorbed configuration and electron transfer of redox species. 展开更多
关键词 Hydroquinone derivatives Iodine-modified ELECTROCHEMISTRY
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Enhancing water-dissociation kinetics and optimizing intermediates adsorption free energy of cobalt phosphide via high-valence Zr incorporating for alkaline water electrolysis 被引量:1
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作者 Huafeng Fan Dongxu Jiao +6 位作者 Jinchang Fan Dewen Wang Bilal Zaman Wei Zhang Lei Zhang Weitao Zheng Xiaoqiang Cui 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第8期119-127,I0005,共10页
Developing high-efficiency electrocatalysts for hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) is required to enhance the sluggish kinetics of water dissociation and optimize the adsorption free e... Developing high-efficiency electrocatalysts for hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) is required to enhance the sluggish kinetics of water dissociation and optimize the adsorption free energy of reaction intermediates.Herein,we tackle this challenge by incorporating high-valence Zr into CoP(ZrxCo_(1-x)P),which significantly accelerates the elementary steps of water electrolysis.Theoretical calculations indicate that the appropriate Zr incorporation effectively expedites the sluggish H2O dissociation kinetics and optimizes the adsorption energy of reaction intermediates for boosting the alkaline water electrolysis.These are confirmed by the experimental results of Zr_(0.06)Co_(0.94)P catalyst that delivers exceptional electrochemical activity.The overpotentials at the current density of 10 mA cm^(-2)(j10) are only 62(HER) and 240 mV(OER) in alkaline media.Furthermore,the Zr_(0.06)Co_(0.94)P/CC‖Zr_(0.06)Co_(0.94)P/CC system exhibits superior overall water splitting activity(1.53 V/j10),surpassing most of the reported bifunctional catalysts.This high-valence Zr incorporation and material design methods explore new avenues for realizing high-performance non-noble metal electrocatalysts. 展开更多
关键词 DFT simulation Water electrolysis Cobalt phosphide High-valence Zr
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Ultrathin origami accordion-like structure of vacancy-rich graphitized carbon nitride for enhancing CO_(2) photoreduction 被引量:1
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作者 Guangri Jia Zhongxu Wang +8 位作者 Ming Gong Ying Wang Lu Hua Li Yilong Dong Lulu Liu Lei Zhang Jingxiang Zhao Weitao Zheng Xiaoqiang Cui 《Carbon Energy》 SCIE CSCD 2023年第4期94-104,共11页
Retaining the ultrathin structure of two-dimensional materials is very important for stabilizing their catalytic performances.However,aggregation and restacking are unavoidable,to some extent,due to the van der Waals ... Retaining the ultrathin structure of two-dimensional materials is very important for stabilizing their catalytic performances.However,aggregation and restacking are unavoidable,to some extent,due to the van der Waals interlayer interaction of two-dimensional materials.Here,we address this challenge by preparing an origami accordion structure of ultrathin twodimensional graphitized carbon nitride(oa-C_(3)N_(4))with rich vacancies.This novel structured oa-C_(3)N_(4) shows exceptional photocatalytic activity for the CO_(2) reduction reaction,which is 8.1 times that of the pristine C_(3)N_(4).The unique structure not only prevents restacking but also increases light harvesting and the density of vacancy defects,which leads to modification of the electronic structure,regulation of the CO_(2) adsorption energy,and a decrease in the energy barrier of the carbon dioxide to carboxylic acid intermediate reaction.This study provides a new avenue for the development of stable highperformance two-dimensional catalytic materials. 展开更多
关键词 C_(3)N_(4) CO_(2)photoreduction molecular modification PHOTOCATALYSTS solar energy conversion two-dimensional materials
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Chemical bonding of perovskite LaFeO_(3) with Li_(1.2)Mn_(0.6)Ni_(0.2)O_(2) to moderate anion redox for achieving high cycling stability
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作者 Xin Zhang Chaochao Fu +5 位作者 Dong Luo Xiaoqing Liu Qiao Wang Baoyun Li Guangshe Li Liping Li 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第4期330-339,共10页
Oxygen anion redox reaction provides a high theoretical capacity for Li-rich manganese-based cathodes.However,irreversible surface oxygen release often results in further oxygen loss and exacerbates the decomposition ... Oxygen anion redox reaction provides a high theoretical capacity for Li-rich manganese-based cathodes.However,irreversible surface oxygen release often results in further oxygen loss and exacerbates the decomposition of the electrolyte,which could reduce the capacity contribution from the anionic redox and produce more acidic substances to corrode the surface of the material.In this paper,the surface oxygen release is suppressed by moderating oxygen anion redox activity via constructing chemical bonds between M(M=Fe and La)in LaFeO_(3)and surface oxygen anions of Li_(1.2)Mn_(0.6)Ni_(0.2)O_(2).The constructed interface layer stabilizes the surface lattice oxygen and retards the electrolyte from being attacked by the nucleophilic oxygen generated in the process of oxygen release,as evidenced by Differential Electrochemical Mass Spectrometry(DEMS)and X-ray Photoelectron Spectroscopy(XPS)detections.Moreover,in the charge and discharge process,the formed FeF_(3),located at the cathode electrolyte interfacial layer,is conducive to the stability of the cathode surface.The modified Li_(1.2)Mn_(0.6)Ni_(0.2)O_(2)electrode with 3 wt%LaFeO_(13)exhibits a high specific capacity of 189.5 mA h g-at 1C(200 mA g^(-1))after 150 cycles with capacity retentions of 96.6%,and 112.6 mA h g^(-1)(84.7%)at 5C after 200 cycles higher than the pristine sample.This study provides a rational design chemical bonding method to suppress the oxygen release from the cathode surface and enhance cyclic stability. 展开更多
关键词 Lithium battery Li_(1.2)Mn_(0.6)Ni_(0.2)O_(2) Oxygen release Interface chemical bond Electrolyte decomposition
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Splitting of Degenerate Superatomic Molecular Orbitals Determined by Point Group Symmetry
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作者 王瑞 李佳芮 +2 位作者 刘中华 万晨曦 王志刚 《Chinese Physics Letters》 SCIE EI CAS CSCD 2023年第11期1-5,共5页
We first confirm an idea obtained from first-principles calculations,which is in line with symmetry theory:Although superatomic molecular orbitals(SAMOs) can be classified according to their angular momentum similar t... We first confirm an idea obtained from first-principles calculations,which is in line with symmetry theory:Although superatomic molecular orbitals(SAMOs) can be classified according to their angular momentum similar to atomic orbitals,SAMOs with the same angular momentum split due to the point group symmetry of superatoms.Based on this idea,we develop a method to quantitatively modulate the splitting spacing of molecular orbitals in a superatom by changing its structural symmetry or by altering geometric parameters with the same symmetry through expansion and compression processes.Moreover,the modulation of the position crossover is achieved between the lowest unoccupied molecular orbital and the highest occupied molecular orbital originating from the splitting of different angular momenta,leading to an effective reduction in system energy.This phenomenon is in line with the implication of the Jahn–Teller effect.This work provides insights into understanding and regulating the electronic structures of superatoms. 展开更多
关键词 EFFECT SYMMETRY ANGULAR
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Dual-doping for enhancing chemical stability of functional anionic units in sulfide for high-performance all-solid-state lithium batteries
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作者 Peiwen Yu Niaz Ahmad +6 位作者 Jie Yang Chaoyuan Zeng Xiaoxiao Liang Weiming Huang Mei Ni Pengcheng Mao Wen Yang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第11期382-390,I0009,共10页
The sulfide-based solid-state electrolytes(SEs)reactivity toward moisture and Li-metal are huge barriers that impede their large-scale manufactu ring and applications in all-solid-state lithium batteries(ASSLBs).Herei... The sulfide-based solid-state electrolytes(SEs)reactivity toward moisture and Li-metal are huge barriers that impede their large-scale manufactu ring and applications in all-solid-state lithium batteries(ASSLBs).Herein,we proposed an Al and O dual-doped strategy for Li_(3)PS_(4)SE to regulate the chemical/electrochemical stability of anionic PS_(4)^(3-)tetrahedra to mitigate structural hydrolysis and parasitic reactions at the SE/Li interface.The optimized Li_(3.08)A_(10.04)P_(0.96)S_(3.92)O_(0.08)SE presents the highestσLi+of 3.27 mS cm^(-1),which is~6.8 times higher than the pristine Li_(3)PS_(4)and excellently inhibits the structural hydrolysis for~25 min@25%humidity at RT.DFT calculations confirmed that the enhanced chemical stability was revealed to the intrinsically stable entities,e.g.,POS33-units.Moreover,Li_(3.08)Al_(0.04)P_(0.96)S_(3.92)O_(0.08)SE cycled stably in Li//Li symmetric cell over 1000 h@0.1 mA cm^(-2)/0.1 mA h cm^(-2),could be revealed to Li-Al alloy and Li_(2)Oat SE/Li interface impeding the growth of Li-dendrites during cycling.Resultantly,LNO@LCO/Li_(3.08)Al_(0.04)P_(0.96)S_(3.92)O_(0.08)/Li-In cell delivered initial discharge capacities of 129.8 mA h g^(-1)and 83.74%capacity retention over 300 cycles@0.2 C at RT.Moreover,the Li_(3.08)Al_(0.04)P_(0.96)S_(3.92)O_(0.08)SE presented>90%capacity retention over 200 and 300 cycles when the cell was tested with LiNi_(0.8)Co_(0.15)Al_(0.05)O_(2)(NCA)cathode material vs.5 and 10 mg cm^(-2)@RT. 展开更多
关键词 Dual doping High Li^(+) conductivity Air-stability Pos_(3)^(3-) functional units Stable SE/electrode interface
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Ultraviolet‑Irradiated All‑Organic Nanocomposites with Polymer Dots for High‑Temperature Capacitive Energy Storage 被引量:1
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作者 Jiale Ding Yao Zhou +5 位作者 Wenhan Xu Fan Yang Danying Zhao Yunhe Zhang Zhenhua Jiang Qing Wang 《Nano-Micro Letters》 SCIE EI CSCD 2024年第3期398-406,共9页
Polymer dielectrics capable of operating efficiently at high electric fields and elevated temperatures are urgently demanded by next-generation electronics and electrical power systems.While inorganic fillers have bee... Polymer dielectrics capable of operating efficiently at high electric fields and elevated temperatures are urgently demanded by next-generation electronics and electrical power systems.While inorganic fillers have been extensively utilized to improved high-temperature capacitive performance of dielectric polymers,the presence of thermodynamically incompatible organic and inorganic components may lead to concern about the long-term stability and also complicate film processing.Herein,zero-dimensional polymer dots with high electron affinity are introduced into photoactive allyl-containing poly(aryl ether sulfone)to form the all-organic polymer composites for hightemperature capacitive energy storage.Upon ultraviolet irradiation,the crosslinked polymer composites with polymer dots are efficient in suppressing electrical conduction at high electric fields and elevated temperatures,which significantly reduces the high-field energy loss of the composites at 200℃.Accordingly,the ultraviolet-irradiated composite film exhibits a discharged energy density of 4.2 J cm^(−3)at 200℃.Along with outstanding cyclic stability of capacitive performance at 200℃,this work provides a promising class of dielectric materials for robust high-performance all-organic dielectric nanocomposites. 展开更多
关键词 High-temperature energy storage Polymer dots Ultraviolet irradiation All-organic composite dielectrics
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Atomic Dispersed Hetero‑Pairs for Enhanced Electrocatalytic CO_(2)Reduction
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作者 Zhaoyong Jin Meiqi Yang +13 位作者 Yilong Dong Xingcheng Ma Ying Wang Jiandong Wu Jinchang Fan Dewen Wang Rongshen Xi Xiao Zhao Tianyi Xu Jingxiang Zhao Lei Zhang David J.Singh Weitao Zheng Xiaoqiang Cui 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第1期55-67,共13页
Electrochemical carbon dioxide reduction reaction(CO_(2)RR)involves a variety of intermediates with highly correlated reaction and ad-desorption energies,hindering optimization of the catalytic activity.For example,in... Electrochemical carbon dioxide reduction reaction(CO_(2)RR)involves a variety of intermediates with highly correlated reaction and ad-desorption energies,hindering optimization of the catalytic activity.For example,increasing the binding of the*COOH to the active site will generally increase the*CO desorption energy.Breaking this relationship may be expected to dramatically improve the intrinsic activity of CO_(2)RR,but remains an unsolved challenge.Herein,we addressed this conundrum by constructing a unique atomic dispersed hetero-pair consisting of Mo-Fe di-atoms anchored on N-doped carbon carrier.This system shows an unprecedented CO_(2)RR intrinsic activity with TOF of 3336 h−1,high selectivity toward CO production,Faradaic efficiency of 95.96%at−0.60 V and excellent stability.Theoretical calculations show that the Mo-Fe diatomic sites increased the*COOH intermediate adsorption energy by bridging adsorption of*COOH intermediates.At the same time,d-d orbital coupling in the Mo-Fe di-atom results in electron delocalization and facilitates desorption of*CO intermediates.Thus,the undesirable correlation between these steps is broken.This work provides a promising approach,specifically the use of di-atoms,for breaking unfavorable relationships based on understanding of the catalytic mechanisms at the atomic scale. 展开更多
关键词 CO_(2)reduction reaction Atomic dispersed catalyst Hetero-diatomic pair Ad-desorption energy Linear scaling relation
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Dynamic Microwave-assisted Extraction of Flavonoids from Radix Scutellariae 被引量:12
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作者 YOU Jing-yan ZHANG Hua-rong DING Lan XIAO Ting-ting ZHANG Han-qi SONG Da-qian 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2007年第2期148-153,共6页
Dynamic microwave-assisted extraction(DMAE) of flavonoids from Radix Scutellarie was described in this article. A TM010 microwave resonant cavity was used as the energy coupler. Several parameters of DMAE, including... Dynamic microwave-assisted extraction(DMAE) of flavonoids from Radix Scutellarie was described in this article. A TM010 microwave resonant cavity was used as the energy coupler. Several parameters of DMAE, including concentration, flow rate, volume of the extraction solvent, and irradiation power, were optimized. The extraction was performed under the optimum conditions for the extraction of total flavonoids. The total flavonoids were determined by UV-Vis spectrophotometry. The main bioactive components, including baicalin, baicalein, and wogonin, were determined by HPLC. The extraction yields of the tlavonoids obtained by DMAE were compared with those obtained by pressurized microwave assisted extraction ( PMAE), ultrasonic extraction ( UE ), soxhlet extraction ( SE ), and reflux extraction( RE), and these results indicate that DMAE is a good alternative method for the extraction of flavonoids from Radix Scutellade. 展开更多
关键词 DMAE FLAVONOIDS UV-Vis spectrophotometry HPLC
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A review of defect engineering in two‐dimensional materials for electrocatalytic hydrogen evolution reaction 被引量:8
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作者 Tianmi Tang Zhenlu Wang Jingqi Guan 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第3期636-678,共43页
The exploration of efficient and earth‐rich electrocatalysts for electrochemical reactions is critical to the implementation of large‐scale green energy conversion and storage techniques.Two‐dimensional(2D)material... The exploration of efficient and earth‐rich electrocatalysts for electrochemical reactions is critical to the implementation of large‐scale green energy conversion and storage techniques.Two‐dimensional(2D)materials with distinctive structural and electrochemical properties provide fertile soil for researchers to harvest basic science and emerging applications,which can be divided into metal‐free materials(such as graphene,carbon nitride and black phosphorus)and transition metal‐based materials(such as halogenides,phosphates,oxides,hydroxides,and MXenes).For faultless 2D materials,they usually exhibit poor electrochemical hydrogen evolution reaction(HER)activity because only edge sites can be available while the base surface is chemically inactive.Defect engineering is an effective strategy to generate active sites in 2D materials for improving electrocatalytic activity.This review presents feasible design strategies for constructing defect sites(including edge defects,vacancy defects and dopant derived defects)in 2D materials to improve their HER performance.The essential relationships between defect structures and electrocatalytic HER performance are discussed in detail,providing valuable guidance for rationally fabricating efficient HER electrocatalysts.The hydrogen adsorption/desorption energy can be optimized by constructing defect sites at different locations and by adjusting the local electronic structure to form unsaturated coordination states for efficient HER. 展开更多
关键词 DEFECT Hydrogen evolution reaction Hydrogen adsorption/desorption energy Two‐dimensional material VACANCY
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Novel Strategy for Synthesis of High Quality CdTe Nanocrystals in Aqueous Solution 被引量:21
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作者 YAN Yu-xi MU Ying +5 位作者 FENG Guo-dong ZHANG Lei ZHU Lin-lin XU Ling YANG Rui JIN Qin-han 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2008年第1期8-14,共7页
A novel aqueous route for the synthesis of high-quality CdTe nanocrystals(NCs) is presented in this article. With both glutathione(GSH) and cysteine[n(GSH):n(cysteine)=1:3] as stabilizers, high-quality CdTe ... A novel aqueous route for the synthesis of high-quality CdTe nanocrystals(NCs) is presented in this article. With both glutathione(GSH) and cysteine[n(GSH):n(cysteine)=1:3] as stabilizers, high-quality CdTe NCs with controllable photoluminescence(PL) wavelength from 500 to 630 nm can be prepared within 4 h. As-prepared CdTe NCs show higher photoluminescence quantum yields(PLQY) compared with CdTe NCs prepared via other aqueous methods. When the fluorescent emission peak appeared in orange-red window, the PLQY reaches 70% or above at room temperature without any post-preparative treatment. 展开更多
关键词 CdTe nanocrystal Quantum dot synthesis GSH CYSTEINE X-Ray photoelectron spectroscopy
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Relationship between Crystal Structure and Luminescence Properties of (Y_(0.96-x)Ln_xCe_(0.04))_3Al_5O_(12) (Ln=Gd, La, Lu) Phosphors 被引量:13
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作者 孔丽 甘树才 +1 位作者 洪广言 张吉林 《Journal of Rare Earths》 SCIE EI CAS CSCD 2007年第6期692-696,共5页
The doping effects of La^3+, Gd^3+ and Lu^3+ on the crystal structure and luminescence properties of (Yo96-x LnxCe0.04)3Al5O12(Ln = Gd, La, Lu) phosphors were studied. The X-ray diffraction patterns presented t... The doping effects of La^3+, Gd^3+ and Lu^3+ on the crystal structure and luminescence properties of (Yo96-x LnxCe0.04)3Al5O12(Ln = Gd, La, Lu) phosphors were studied. The X-ray diffraction patterns presented that with the inerease of the doping concentrations of La^3+ and Gd^3+ ions, the d-value of (Y0.96-xLnxCe0.04)3Al5O12 (Ln = Gd, La) inereased and the larger the doping ion, the stronger the effect would be. The doping amount causing phase transition in (Y0.96-xLnxCe0.04)3Al5O12 decreased with the inerease of the ionic radii of the doping lanthanide ions (La^3+: 0.106 nm, Gd^3+: 0. 094 nm, Lu^3+ : 0.083 nm). The bigger doping ion of Gd^3+ made the emission of (Y0.96-xGdxCe0.04)3Al5O12 move to red spectral region, but the smaller one of Lu^3+ made it blue. 展开更多
关键词 LUMINESCENCE YAG: Ce doping of lanthanide ions rare earths
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Determination of Seven Major Ginsenosides in Different Parts of Panax quinquefolius L.(American Ginseng) with Different Ages 被引量:14
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作者 ZHANG Kun WANG Xiao +5 位作者 DING Lan LI Juan QU Chen-ling CHEN Li-gang JIN Hai-yan ZHANG Han-qi 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2008年第6期707-711,共5页
Ginsenosides Rgl, Re, Rb1, Rc, Rb2, Rb3, and Rd in different parts of the American ginseng plant were investigated. The extraction process was a pressurized microwave-assisted extraction(PMAE). The seven ginsenoside... Ginsenosides Rgl, Re, Rb1, Rc, Rb2, Rb3, and Rd in different parts of the American ginseng plant were investigated. The extraction process was a pressurized microwave-assisted extraction(PMAE). The seven ginsenosides were separated and determined by high-performance liquid chromatography(HPLC) with a ultraviolet(UV) detector, at 203 nm. The experiment results showed significant variations in the individual ginsenoside contents of the American ginseng in different parts and ages of the plant. The results demonstrated that the leaves, root hairs, and rhizomes of Panax quinquefolius L. contained higher ginsenoside contents, followed by the main roots and stems. The leaves contained dramatically higher levels of ginsenoside Rg1 Rb3, and Rd than the other four parts. Higher contents of Rb1 and Re were present in the main roots, root hairs, and rhizomes. The amount of ginsenoside content in the stems was the lowest. The total content of the seven ginsenosides in main roots, root hairs and rhizomes increased with the age of the plant. In contrast, the ginsenoside contents in the leaves and stems decreased with a year of growth. 展开更多
关键词 American ginseng GINSENOSIDE High performance liquid chromatography Pressurized microwave-assisted extraction
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Strategies to improve electrocatalytic and photocatalytic performance of two-dimensional materials for hydrogen evolution reaction 被引量:12
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作者 Saisai Li Jianrui Sun Jingqi Guan 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第4期511-556,共46页
Two-dimensional materials(2D)with unique physicochemical properties have been widely studied for their use in many applications,including as hydrogen evolution catalysts to improve the efficiency of water splitting.Re... Two-dimensional materials(2D)with unique physicochemical properties have been widely studied for their use in many applications,including as hydrogen evolution catalysts to improve the efficiency of water splitting.Recently,typical 2D materials MoS2,graphene,MXenes,and black phosphorus have been widely investigated for their application in the hydrogen evolution reaction(HER).In this review,we summarize three efficient strategies—defect engineering,heterostructure formation,and heteroatom doping—for improving the HER performance of 2D catalysts.The d-band theory,density of states,and Fermi energy level are discussed to provide guidance for the design and construction of novel 2D materials.The challenges and prospects of 2D materials in the HER are also considered. 展开更多
关键词 GRAPHENE Hydrogen evolution Molybdenum disulfide MXenes Black phosphorus Two-dimensional material
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