The ability to control the preparation of one-dimensional(1D)porous carbon nanorods,especially during rapid polymerization,is key to their practical application.We report a method for synthesizing 1D porous carbon nan...The ability to control the preparation of one-dimensional(1D)porous carbon nanorods,especially during rapid polymerization,is key to their practical application.We report a method for synthesizing 1D porous carbon nanorods,characterized by the formation of rod-like mi-celles that are assembled from sodium palmitate and Pluronic F127,facilitated by protonated melamine,and subsequently converted into melamine-based N-doped polymer nanorods which were carbonized to produce the corres-ponding N-doped carbon nanorods.The specific capacitance of the supercapacitor used the as-pre-pared N-doped nanorods as electrode material in a three-electrode system was calculated to be 301.66 F g^(-1) at a current density of 0.2 A g^(-1),with an ultra-high specific surface area normalized capacitance of up to 67.07μF cm^(-2).The N-doping and their one-dimensionality give the nanorods a low internal resistance and good stability,making them well suited for fundamental studies and practical applications ranging from materials chemistry to electrochemical energy storage.展开更多
To optimize the CO_(2) adsorption performance of carbon materials,this study proposed a preparation method for biomass-based porous carbon through hydrothermal carbonization coupled with nitrogen source optimization a...To optimize the CO_(2) adsorption performance of carbon materials,this study proposed a preparation method for biomass-based porous carbon through hydrothermal carbonization coupled with nitrogen source optimization and K_(2)CO_(3) activation.The effects of different nitrogen sources(urea,piperazine,melamine,and polyaniline)and activation temperatures on the physicochemical features and CO_(2) adsorption characteristics of the porous carbons were systematically investigated.The results indicated that different nitrogen sources showed varying impacts on the CO_(2) uptake of porous carbons,and not all nitrogen sources enhanced the adsorption performance.The urea and piperazine doped porous carbons exhibited relatively low nitrogen contents and specific surface areas.Whereas the melamine doped carbons showed higher nitrogen contents and specific surface areas,but lacked narrow micropores,limiting their CO_(2) adsorption performance.In contrast,PAC-700,prepared using polyaniline as nitrogen source,featured a well-developed pore structure,abundant narrow micropores and pyrrolic-N groups,endowing it with enhanced CO_(2) adsorption capability.At 0℃/1 bar and 25℃/1 bar,the CO_(2) uptake of PAC-700 reached 6.85 and 4.64 mmol/g,respectively.Additionally,PAC-700 maintained a CO_(2) uptake retention ratio of 99%after 5 adsorption-desorption cycles and exhibited good CO_(2)/N_(2) selectivity of 22.4−51.6.These findings highlighted the advantageous CO_(2) adsorption performance of PAC-700,indicating its substantial application potential in the domain of carbon capture.展开更多
在非霍奇金淋巴瘤(non-Hodgkin's lymphoma,NHL)中,弥漫大B细胞淋巴瘤(diffuse large B cell lymphoma,DLBCL)的发生率最高,其异质性明显。利妥昔单抗的出现极大改善了患者的预后及生存,其联合CHOP成为经典一线治疗方案,50%~70%患...在非霍奇金淋巴瘤(non-Hodgkin's lymphoma,NHL)中,弥漫大B细胞淋巴瘤(diffuse large B cell lymphoma,DLBCL)的发生率最高,其异质性明显。利妥昔单抗的出现极大改善了患者的预后及生存,其联合CHOP成为经典一线治疗方案,50%~70%患者可治愈,但仍有30%~50%因耐药等原因反应差或在缓解后复发。复发难治DLBCL,尤其是无法自体造血干细胞移植或移植后复发病人的治疗是目前亟待解决的问题。随着对靶向免疫治疗研究的不断深入,许多药物不断进入临床应用或正在开发中,该文主要就单克隆抗体、双特异性抗体、抗体药物偶联物、选择性核出口蛋白抑制剂、嵌合抗原受体T细胞、程序性死亡受体/配体1抑制剂等药物作一简要综述。展开更多
Freshwater scarcity has emerged as a critical global environmental challenge.Flow-electrode capacitive deionization(FCDI)represents a promising technology for achieving efficient and low-energy seawater desalination.T...Freshwater scarcity has emerged as a critical global environmental challenge.Flow-electrode capacitive deionization(FCDI)represents a promising technology for achieving efficient and low-energy seawater desalination.This study presents a novel flow-electrode material,nitrogen-doped porous carbon(NPC),which is derived from biomass and demonstrates both cost-effectiveness and high performance.The NPC material is synthesized from bean shells through high-temperature pre-carbonization followed by activation with KHCO_(3),resulting in a rich porous structure,increased specific surface area,and high graphitization degree,which collectively confer superior capacitance performance compared to activated carbon(AC).Desalination experiments indicate that the FCDI performance of the NPC flow-electrode surpasses that of the AC flow-electrode.Specifically,at a voltage of 2.5 V in a 6 g·L^(-1)NaCl solution,the NPC system achieves an average salt removal rate(ASRR)of 104.9 μg·cm^(-2)·min^(-1),with a charge efficiency(CE)of 94.0%and an energy consumption(EC)of only 4.4 kJ·g^(-1).Furthermore,the NPC-based FCDI system exhibits commendable desalination cycling stability,maintaining relatively stable energy consumption and efficiency after prolonged continuous desalination cycles.This research holds significant implications for the advancement of environmentally friendly,low-cost,high-performance FCDI systems for large-scale applications.展开更多
Microalgae are one of the promising feedstocks for biorefinery,contributing significantly to net-zero emissions through carbon capture and utilization.However,the disposal of microalgal byproducts from the manufacturi...Microalgae are one of the promising feedstocks for biorefinery,contributing significantly to net-zero emissions through carbon capture and utilization.However,the disposal of microalgal byproducts from the manufacturing process causes additional environmental pollution,thus,a new application strategy is required.In this study,the Tetraselmis suecica byproduct from the carotenoid extraction process was carbonized and converted into biochar.The converted biochar was proved to be nitrogen-doped biochar(NDB),up to 4.69%,with a specific surface area of 206.59m^(2)/g andwas used as an electrode for a supercapacitor.The NDB electrode(NDB-E)in half-cell showed a maximum specific capacitance of 191 F/g.In a full-cell test,the NDB-E exhibited a high energy density of 7.396 Wh/kg and a high-power density of 18,100 W/kg,and maintained specific capacity of 95.5%after charge and discharge of 10,000 cycles.In conclusion,our study demonstrated that the carotenoid-extracted microalgal byproducts are a useful resource for the supercapacitor production.This approach is the first to convert T.suecica into active materials for supercapacitors.展开更多
The effi ciency of photocatalytic ammonia(NH_(3))synthesis is severely limited by the extremely diffi cult activation of N_(2) owing to its high N≡N triple bond energy.To address this challenge,we propose an N-doping...The effi ciency of photocatalytic ammonia(NH_(3))synthesis is severely limited by the extremely diffi cult activation of N_(2) owing to its high N≡N triple bond energy.To address this challenge,we propose an N-doping strategy to facilitate the N_(2) activation.Our strategy involves optimizing the electronic structure of the metal active sites by modulating the coordination element.First,we introduce fi ve diff erent N-coordination ligands with distinct steric hindrances and N electron densities(2-methyl-imidazole(MI),isoindolin-1-one(II),1,2-benzisothiazolin-3-one(BIT),benzo[d]isoxazol-3-ol(BIX),and terephthalamide(TA))into an amino-functionalized metal-organic framework(MOF),NH_(2)-MIL-68(NM),to construct the N-coordination via the partial replacement of the O-coordination in the metal clusters.Electrochemical impedance spectroscopy and photocur-rent analysis demonstrate that N-doping enhances electron transfer and carrier separation.Moreover,incorporating ligands with moderate sizes and steric hindrances(II,BIT,and BIX)more eff ectively boosts the carrier separation efficiency than incorporating small(MI)or large(TA)ligands.Furthermore,the N-doped MOF modifi ed with BIT(in which N exhibits a moderate electron density)exhibits the strongest carrier separation capability.Concurrently,the X-ray photoelectron spec-troscopy,density functional theory,and N_(2) temperature-programmed desorption results confi rm that the established low-electronegativity N-coordination elevates the electron density of the metal active sites,which consequently enhances the N_(2) activation process.The systematic optimization of the N-coordinating ligand species and doping concentrations allows the optimal NM-0.5BIT to achieve a NH 3 production rate of 175.5μmol/(g·h).The proposed N-doping strategy off ers several insights into the activation of inert molecules and the development of organic framework photocatalysts.展开更多
As one of the alloy-type lithium-ion electrodes,Bi has outstanding application prospects for large volume capacity(3800 mAh·cm^(-3))and high electronic conductivity(1.4×10^(7)S·m^(-1)).However,the fast-...As one of the alloy-type lithium-ion electrodes,Bi has outstanding application prospects for large volume capacity(3800 mAh·cm^(-3))and high electronic conductivity(1.4×10^(7)S·m^(-1)).However,the fast-charging performance is hindered by significant volume expansion(>218%)and a low rate of phase diffusion.To overcome these two problems,an N-doped carbon nanoflower coating layer was elaborately in-situ reconstructed on a multiple-wall Bi microsphere by hydrothermal methods and subsequent calcination in this study.The carbon nanoflowers greatly increase specific surface area(40.0 m^(2)·g^(-1))and alleviate the volume expansion(130%).In addition,the incorporation of N-doped carbon nanoflowers leads to a gradual enhancement in the Li adsorption energy of Bi during the process of lithium insertion and improves the electrical conductivity.Therefore,the contribution rate of pseudo-capacitance reached 87.5%at the scan rate of 0.8 mV·s^(-1),and the Li-ion diffusion coefficient(D_(Li^(+)))was calculated in the range of 10^(-10)to 10^(-12)cm^(2)·s^(-1).The Bi@CNFs anode provided a high specific volumetric capacity of 2117.0 mAh·cm^(-3)at 5C and a high capacity retention ratio of 93.2%after 800 cycles.The Bi@CNFs//LiFePO_(4)full cell also displayed a stable capacity of 113.9 mAh·g^(-1)and energy density of 296.1 Wh·kg^(-1)after 100 cycles with a Coulombic efficiency of 97.6%.The mechanism of fast-charging lithium storage was verified by distribution of relaxation time analysis and density functional theory calculation.This paper provides a new strategy to increase the pseudo-capacitance and reduce the volume expansion for the preparation of alloy-type fast-charging electrodes.展开更多
The development of efficient catalysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is of great significance for the practical application of water splitting in alkaline electrolytes.Transitio...The development of efficient catalysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is of great significance for the practical application of water splitting in alkaline electrolytes.Transition metal sulfide electrocatalysts have been widely recognized as efficient catalysts for water splitting in alkaline media.In this work,an original and efficient synthesis strategy is proposed for the fabrication of asymmetric anode(N-(Co-Cu)S_(x))and cathode(N-CoS/Cu_(2)S).Impressively,these electrodes exhibit superior performance,benefiting from the construction of three-dimensional(3D)structures and the electronic structure adjustment caused by N-doping with increased active sites,improved mass/charge transport and enhanced evolution and release of gas bubbles.Hence,N-(Co-Cu)S_(x)anode exhibits excellent OER performance with only 217 mV overpotential at 10 mA·cm^(-2),while N-CoS/Cu_(2)S cathode possesses excellent HER performance with only 67 mV overpotential at 10 mA·cm^(-2).N-(Co-Cu)S_(x)||N-CoS/Cu_(2)S electrolyzer presents a low cell voltage of 1.53 V at 10 mA·cm^(-2)toward overall water splitting,which is superior to most recently reported transition metal sulfide-based catalysts.展开更多
The contamination of water resources by phenolic compounds(PCs)presents a significant environmental hazard,necessitating the development of novel materials and methodologies for effective mitigation.In this study,a me...The contamination of water resources by phenolic compounds(PCs)presents a significant environmental hazard,necessitating the development of novel materials and methodologies for effective mitigation.In this study,a metallic copper-doped zeolitic imidazolate framework was pyrolyzed and designated as CuNC-20 for the activation of peroxymonosulfate(PMS)to degrade phenol(PE).Cu-NC-20 could effectively address the issue of metal agglomeration while simultaneously diminishing copper dissolution during the activation of PMS reactions.The Cu-NC-20 catalyst exhibited a rapid degradation rate for PE across a broad pH range(3-9)and demonstrated high tolerance towards coexisting ions.According to scavenger experiments and electron paramagnetic resonance analysis,singlet oxygen(^(1)O_(2))and high-valent copperoxo(Cu(Ⅲ))were the predominant reactive oxygen species,indicating that the system was nonradicaldominated during the degradation process.The quantitative structure-activity relationship(QSAR)between the oxidation rate constants of various substituted phenols and Hammett constants was established.It indicated that the Cu-NC-20/PMS system had the optimal oxidation rate constant withσ^(-)correlation and exhibited a typical electrophilic reaction pattern.This study provides a comprehensive understanding of the heterogeneous activation process for the selective removal of phenolic compounds.展开更多
The design and preparation of economic and efficient electrolysis water catalysts is an important part in effectively developing and utilizing hydrogen energy.In this work,novel N-doped carbon nanospheres supported mu...The design and preparation of economic and efficient electrolysis water catalysts is an important part in effectively developing and utilizing hydrogen energy.In this work,novel N-doped carbon nanospheres supported multiple transition metal sulfides(NiWCoS/NC)electrocatalysts were prepared by combining the radiation oxidation synthesis and synchronous carbonization-sulfurization.Initially,the precursor material(NiWCoS/OANI,here OANI refers to oligoaniline)containing sulfurand multiple transition metal(Ni,W,and Co)ions loaded on oligoaniline nanospheres was directly one-pot synthesized at room temperature under γ-ray radiation.Subsequently,NiWCoS/NC electrocatalysts were successfully prepared by calcining the NiWCoS/OANI precursor at 800℃.The electrocatalytic performance of NiWCoS/NC for the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)was characterized by electrochemical analysis methods including linear sweep voltammetry,cyclic voltammetry,chronoamperometry,and electrochemical impedance spectroscopy.The influence of the relative content of the loaded transition metals on the electrocatalytic performance was also investigated.The results indicate that the novel NiWCoS/NC electrocatalyst can significantly reduce the overpotential and Tafel slope for both HER and OER compared to corresponding electrocatalysts with single metal or metal sulfide component.When NiWCoS/NC with a molar ratio of 3:6:10 for W,Co,and S elements was used as electrode material,the overpotentials for HER in 0.5 mol/L H_(2)SO_(4) and OER in 1 mol/L KOH are only 161 mV and 243 mV at a current density of 10 mA/cm^(2),respectively.The Tafel slopes are 74 mV/dec and 88 mV/dec,respectively.The work provides a new direction and method for the design and green facile preparation of high-efficiency overall water splitting catalysts.展开更多
CO_(2) conversion to CO via the reverse water-gas shift(RWGS)reaction is limited by a low CO_(2) conversion rate and CO selectivity.Herein,an efficient RWGS catalyst is constructed through Enteromorpha prolifera–deri...CO_(2) conversion to CO via the reverse water-gas shift(RWGS)reaction is limited by a low CO_(2) conversion rate and CO selectivity.Herein,an efficient RWGS catalyst is constructed through Enteromorpha prolifera–derived N-rich mesoporous biochar(EPBC)supported atomic-level Cu-Mo_(2)C clusters(Cu-Mo_(2)C/EPBC).Unlike traditional acti-vated carbon(AC)supported Cu-Mo_(2)C particles(Cu-Mo_(2)C/AC),the Cu-Mo_(2)C/EPBC not only presents the better graphitization degree and larger specific surface area,but also uniformly andfirmly anchors atomic-level Cu-Mo_(2)C clusters due to the existence of pyridine nitrogen.Furthermore,the pyridine N of Cu-Mo_(2)C/EPBC strengthens an unblocked electron transfer between Mo_(2)C and Cu clusters,as verified by X-ray absorption spectroscopy.As a result,the synergistic effect between pyridinic N anchoring and the clusters interaction in Cu-Mo_(2)C/EPBC facilitates an improved CO selectivity of 99.95%at 500℃ compared with traditional Cu-Mo_(2)C/AC(99.60%),as well as about 3-fold CO_(2) conversion rate.Density functional theory calculations confirm that pyr-idine N-modified carbon activates the local electronic redistribution at Cu-Mo_(2)C clusters,which contributes to the decreased energy barrier of the transition state of CO^(*)+O^(*)+2H^(*),thereby triggering the transformation of rate-limited step during the redox pathway.This biomass-derived strategy opens perspective on producing sustain-able fuels and building blocks through the RWGS reaction.展开更多
文摘The ability to control the preparation of one-dimensional(1D)porous carbon nanorods,especially during rapid polymerization,is key to their practical application.We report a method for synthesizing 1D porous carbon nanorods,characterized by the formation of rod-like mi-celles that are assembled from sodium palmitate and Pluronic F127,facilitated by protonated melamine,and subsequently converted into melamine-based N-doped polymer nanorods which were carbonized to produce the corres-ponding N-doped carbon nanorods.The specific capacitance of the supercapacitor used the as-pre-pared N-doped nanorods as electrode material in a three-electrode system was calculated to be 301.66 F g^(-1) at a current density of 0.2 A g^(-1),with an ultra-high specific surface area normalized capacitance of up to 67.07μF cm^(-2).The N-doping and their one-dimensionality give the nanorods a low internal resistance and good stability,making them well suited for fundamental studies and practical applications ranging from materials chemistry to electrochemical energy storage.
基金supported by the National Key R&D Program(2022YFC3902403)Fundamental Research Funds for the Central Universities(2024JC001,2019JG002)Technology Innovation Special Fund of Jiangsu Province for Carbon Dioxide Emission Peaking and Carbon Neutrality(BE2022307)。
文摘To optimize the CO_(2) adsorption performance of carbon materials,this study proposed a preparation method for biomass-based porous carbon through hydrothermal carbonization coupled with nitrogen source optimization and K_(2)CO_(3) activation.The effects of different nitrogen sources(urea,piperazine,melamine,and polyaniline)and activation temperatures on the physicochemical features and CO_(2) adsorption characteristics of the porous carbons were systematically investigated.The results indicated that different nitrogen sources showed varying impacts on the CO_(2) uptake of porous carbons,and not all nitrogen sources enhanced the adsorption performance.The urea and piperazine doped porous carbons exhibited relatively low nitrogen contents and specific surface areas.Whereas the melamine doped carbons showed higher nitrogen contents and specific surface areas,but lacked narrow micropores,limiting their CO_(2) adsorption performance.In contrast,PAC-700,prepared using polyaniline as nitrogen source,featured a well-developed pore structure,abundant narrow micropores and pyrrolic-N groups,endowing it with enhanced CO_(2) adsorption capability.At 0℃/1 bar and 25℃/1 bar,the CO_(2) uptake of PAC-700 reached 6.85 and 4.64 mmol/g,respectively.Additionally,PAC-700 maintained a CO_(2) uptake retention ratio of 99%after 5 adsorption-desorption cycles and exhibited good CO_(2)/N_(2) selectivity of 22.4−51.6.These findings highlighted the advantageous CO_(2) adsorption performance of PAC-700,indicating its substantial application potential in the domain of carbon capture.
文摘在非霍奇金淋巴瘤(non-Hodgkin's lymphoma,NHL)中,弥漫大B细胞淋巴瘤(diffuse large B cell lymphoma,DLBCL)的发生率最高,其异质性明显。利妥昔单抗的出现极大改善了患者的预后及生存,其联合CHOP成为经典一线治疗方案,50%~70%患者可治愈,但仍有30%~50%因耐药等原因反应差或在缓解后复发。复发难治DLBCL,尤其是无法自体造血干细胞移植或移植后复发病人的治疗是目前亟待解决的问题。随着对靶向免疫治疗研究的不断深入,许多药物不断进入临床应用或正在开发中,该文主要就单克隆抗体、双特异性抗体、抗体药物偶联物、选择性核出口蛋白抑制剂、嵌合抗原受体T细胞、程序性死亡受体/配体1抑制剂等药物作一简要综述。
基金supported by the National Natural Science Foundation of China(52202093)the National College Student Innovation and Entrepreneurship Training Program of Jiangsu University of Science and Technology(202410289005Z).
文摘Freshwater scarcity has emerged as a critical global environmental challenge.Flow-electrode capacitive deionization(FCDI)represents a promising technology for achieving efficient and low-energy seawater desalination.This study presents a novel flow-electrode material,nitrogen-doped porous carbon(NPC),which is derived from biomass and demonstrates both cost-effectiveness and high performance.The NPC material is synthesized from bean shells through high-temperature pre-carbonization followed by activation with KHCO_(3),resulting in a rich porous structure,increased specific surface area,and high graphitization degree,which collectively confer superior capacitance performance compared to activated carbon(AC).Desalination experiments indicate that the FCDI performance of the NPC flow-electrode surpasses that of the AC flow-electrode.Specifically,at a voltage of 2.5 V in a 6 g·L^(-1)NaCl solution,the NPC system achieves an average salt removal rate(ASRR)of 104.9 μg·cm^(-2)·min^(-1),with a charge efficiency(CE)of 94.0%and an energy consumption(EC)of only 4.4 kJ·g^(-1).Furthermore,the NPC-based FCDI system exhibits commendable desalination cycling stability,maintaining relatively stable energy consumption and efficiency after prolonged continuous desalination cycles.This research holds significant implications for the advancement of environmentally friendly,low-cost,high-performance FCDI systems for large-scale applications.
基金supported by the National Research Foundation of Korea(NRF)grant funded by Ministry of Science,ICT(Nos.2018M3A7B4070990,2020R1A2C2103137,2020R1F1A1076359,and 2022R1C1C2011696)the Education(Nos.2020R1A2C2103137 and 2020R1F1A1076359)Materials,Components&Equipment Research Program funded by the Gyeonggi Province。
文摘Microalgae are one of the promising feedstocks for biorefinery,contributing significantly to net-zero emissions through carbon capture and utilization.However,the disposal of microalgal byproducts from the manufacturing process causes additional environmental pollution,thus,a new application strategy is required.In this study,the Tetraselmis suecica byproduct from the carotenoid extraction process was carbonized and converted into biochar.The converted biochar was proved to be nitrogen-doped biochar(NDB),up to 4.69%,with a specific surface area of 206.59m^(2)/g andwas used as an electrode for a supercapacitor.The NDB electrode(NDB-E)in half-cell showed a maximum specific capacitance of 191 F/g.In a full-cell test,the NDB-E exhibited a high energy density of 7.396 Wh/kg and a high-power density of 18,100 W/kg,and maintained specific capacity of 95.5%after charge and discharge of 10,000 cycles.In conclusion,our study demonstrated that the carotenoid-extracted microalgal byproducts are a useful resource for the supercapacitor production.This approach is the first to convert T.suecica into active materials for supercapacitors.
基金the National Natural Science Foundation of China(Nos.21621004,22478295,and 22122809)the National Key Research and Development Program of China(Nos.2022YFC2105902 and 2024YFB4206301)+2 种基金Young Scientifi c and Technological Talents(Level One)in Tianjin(No.QN20230103)Program of Introducing Talents of Discipline to Universities(No.BP0618007)Haihe Laboratory of Sustainable Chemical Transformations.
文摘The effi ciency of photocatalytic ammonia(NH_(3))synthesis is severely limited by the extremely diffi cult activation of N_(2) owing to its high N≡N triple bond energy.To address this challenge,we propose an N-doping strategy to facilitate the N_(2) activation.Our strategy involves optimizing the electronic structure of the metal active sites by modulating the coordination element.First,we introduce fi ve diff erent N-coordination ligands with distinct steric hindrances and N electron densities(2-methyl-imidazole(MI),isoindolin-1-one(II),1,2-benzisothiazolin-3-one(BIT),benzo[d]isoxazol-3-ol(BIX),and terephthalamide(TA))into an amino-functionalized metal-organic framework(MOF),NH_(2)-MIL-68(NM),to construct the N-coordination via the partial replacement of the O-coordination in the metal clusters.Electrochemical impedance spectroscopy and photocur-rent analysis demonstrate that N-doping enhances electron transfer and carrier separation.Moreover,incorporating ligands with moderate sizes and steric hindrances(II,BIT,and BIX)more eff ectively boosts the carrier separation efficiency than incorporating small(MI)or large(TA)ligands.Furthermore,the N-doped MOF modifi ed with BIT(in which N exhibits a moderate electron density)exhibits the strongest carrier separation capability.Concurrently,the X-ray photoelectron spec-troscopy,density functional theory,and N_(2) temperature-programmed desorption results confi rm that the established low-electronegativity N-coordination elevates the electron density of the metal active sites,which consequently enhances the N_(2) activation process.The systematic optimization of the N-coordinating ligand species and doping concentrations allows the optimal NM-0.5BIT to achieve a NH 3 production rate of 175.5μmol/(g·h).The proposed N-doping strategy off ers several insights into the activation of inert molecules and the development of organic framework photocatalysts.
基金supported by the project of the National Natural Science Foundation of China(NSFC,Nos.5216040127,52164048 and U1802256)Central Guidance for Local Science and Technology Development Funds(No.202107AB110011)the Analysis and Test Funds of Kunming University of Science and Technology(No.2021M0202230188).
文摘As one of the alloy-type lithium-ion electrodes,Bi has outstanding application prospects for large volume capacity(3800 mAh·cm^(-3))and high electronic conductivity(1.4×10^(7)S·m^(-1)).However,the fast-charging performance is hindered by significant volume expansion(>218%)and a low rate of phase diffusion.To overcome these two problems,an N-doped carbon nanoflower coating layer was elaborately in-situ reconstructed on a multiple-wall Bi microsphere by hydrothermal methods and subsequent calcination in this study.The carbon nanoflowers greatly increase specific surface area(40.0 m^(2)·g^(-1))and alleviate the volume expansion(130%).In addition,the incorporation of N-doped carbon nanoflowers leads to a gradual enhancement in the Li adsorption energy of Bi during the process of lithium insertion and improves the electrical conductivity.Therefore,the contribution rate of pseudo-capacitance reached 87.5%at the scan rate of 0.8 mV·s^(-1),and the Li-ion diffusion coefficient(D_(Li^(+)))was calculated in the range of 10^(-10)to 10^(-12)cm^(2)·s^(-1).The Bi@CNFs anode provided a high specific volumetric capacity of 2117.0 mAh·cm^(-3)at 5C and a high capacity retention ratio of 93.2%after 800 cycles.The Bi@CNFs//LiFePO_(4)full cell also displayed a stable capacity of 113.9 mAh·g^(-1)and energy density of 296.1 Wh·kg^(-1)after 100 cycles with a Coulombic efficiency of 97.6%.The mechanism of fast-charging lithium storage was verified by distribution of relaxation time analysis and density functional theory calculation.This paper provides a new strategy to increase the pseudo-capacitance and reduce the volume expansion for the preparation of alloy-type fast-charging electrodes.
基金supported by the Science and Technology Project of Southwest Petroleum University(No.2021JBGS03)the Local Science and Technology Development Fund Projects Guided by the Central Government of China(No.2021ZYD0060)+2 种基金the National Natural Science Foundation of China(Nos.22209143 and 52371241)Guangdong High-level Innovation Institute Project(Nos.2021B0909050001 and 2021CX02L365)Guangdong Basic and Applied Basic Research Foundation(No.2023B1515120095).
文摘The development of efficient catalysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is of great significance for the practical application of water splitting in alkaline electrolytes.Transition metal sulfide electrocatalysts have been widely recognized as efficient catalysts for water splitting in alkaline media.In this work,an original and efficient synthesis strategy is proposed for the fabrication of asymmetric anode(N-(Co-Cu)S_(x))and cathode(N-CoS/Cu_(2)S).Impressively,these electrodes exhibit superior performance,benefiting from the construction of three-dimensional(3D)structures and the electronic structure adjustment caused by N-doping with increased active sites,improved mass/charge transport and enhanced evolution and release of gas bubbles.Hence,N-(Co-Cu)S_(x)anode exhibits excellent OER performance with only 217 mV overpotential at 10 mA·cm^(-2),while N-CoS/Cu_(2)S cathode possesses excellent HER performance with only 67 mV overpotential at 10 mA·cm^(-2).N-(Co-Cu)S_(x)||N-CoS/Cu_(2)S electrolyzer presents a low cell voltage of 1.53 V at 10 mA·cm^(-2)toward overall water splitting,which is superior to most recently reported transition metal sulfide-based catalysts.
基金the financial support from Sichuan Program of Science and Technology(No.2021ZDZX0012)the National Natural Science Foundation of China(No.52200105)。
文摘The contamination of water resources by phenolic compounds(PCs)presents a significant environmental hazard,necessitating the development of novel materials and methodologies for effective mitigation.In this study,a metallic copper-doped zeolitic imidazolate framework was pyrolyzed and designated as CuNC-20 for the activation of peroxymonosulfate(PMS)to degrade phenol(PE).Cu-NC-20 could effectively address the issue of metal agglomeration while simultaneously diminishing copper dissolution during the activation of PMS reactions.The Cu-NC-20 catalyst exhibited a rapid degradation rate for PE across a broad pH range(3-9)and demonstrated high tolerance towards coexisting ions.According to scavenger experiments and electron paramagnetic resonance analysis,singlet oxygen(^(1)O_(2))and high-valent copperoxo(Cu(Ⅲ))were the predominant reactive oxygen species,indicating that the system was nonradicaldominated during the degradation process.The quantitative structure-activity relationship(QSAR)between the oxidation rate constants of various substituted phenols and Hammett constants was established.It indicated that the Cu-NC-20/PMS system had the optimal oxidation rate constant withσ^(-)correlation and exhibited a typical electrophilic reaction pattern.This study provides a comprehensive understanding of the heterogeneous activation process for the selective removal of phenolic compounds.
基金supported by the National Natural Science Foundation of China (No.51973205 and No.51773189)the Fundamental Research Funds for the Central Universities (WK3450000005 and WK3450000006)。
文摘The design and preparation of economic and efficient electrolysis water catalysts is an important part in effectively developing and utilizing hydrogen energy.In this work,novel N-doped carbon nanospheres supported multiple transition metal sulfides(NiWCoS/NC)electrocatalysts were prepared by combining the radiation oxidation synthesis and synchronous carbonization-sulfurization.Initially,the precursor material(NiWCoS/OANI,here OANI refers to oligoaniline)containing sulfurand multiple transition metal(Ni,W,and Co)ions loaded on oligoaniline nanospheres was directly one-pot synthesized at room temperature under γ-ray radiation.Subsequently,NiWCoS/NC electrocatalysts were successfully prepared by calcining the NiWCoS/OANI precursor at 800℃.The electrocatalytic performance of NiWCoS/NC for the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)was characterized by electrochemical analysis methods including linear sweep voltammetry,cyclic voltammetry,chronoamperometry,and electrochemical impedance spectroscopy.The influence of the relative content of the loaded transition metals on the electrocatalytic performance was also investigated.The results indicate that the novel NiWCoS/NC electrocatalyst can significantly reduce the overpotential and Tafel slope for both HER and OER compared to corresponding electrocatalysts with single metal or metal sulfide component.When NiWCoS/NC with a molar ratio of 3:6:10 for W,Co,and S elements was used as electrode material,the overpotentials for HER in 0.5 mol/L H_(2)SO_(4) and OER in 1 mol/L KOH are only 161 mV and 243 mV at a current density of 10 mA/cm^(2),respectively.The Tafel slopes are 74 mV/dec and 88 mV/dec,respectively.The work provides a new direction and method for the design and green facile preparation of high-efficiency overall water splitting catalysts.
基金support from National Natural Science Foundation of China(32101474 and 42377249)National Key Research and Development Program of China(2023YFD2201605).
文摘CO_(2) conversion to CO via the reverse water-gas shift(RWGS)reaction is limited by a low CO_(2) conversion rate and CO selectivity.Herein,an efficient RWGS catalyst is constructed through Enteromorpha prolifera–derived N-rich mesoporous biochar(EPBC)supported atomic-level Cu-Mo_(2)C clusters(Cu-Mo_(2)C/EPBC).Unlike traditional acti-vated carbon(AC)supported Cu-Mo_(2)C particles(Cu-Mo_(2)C/AC),the Cu-Mo_(2)C/EPBC not only presents the better graphitization degree and larger specific surface area,but also uniformly andfirmly anchors atomic-level Cu-Mo_(2)C clusters due to the existence of pyridine nitrogen.Furthermore,the pyridine N of Cu-Mo_(2)C/EPBC strengthens an unblocked electron transfer between Mo_(2)C and Cu clusters,as verified by X-ray absorption spectroscopy.As a result,the synergistic effect between pyridinic N anchoring and the clusters interaction in Cu-Mo_(2)C/EPBC facilitates an improved CO selectivity of 99.95%at 500℃ compared with traditional Cu-Mo_(2)C/AC(99.60%),as well as about 3-fold CO_(2) conversion rate.Density functional theory calculations confirm that pyr-idine N-modified carbon activates the local electronic redistribution at Cu-Mo_(2)C clusters,which contributes to the decreased energy barrier of the transition state of CO^(*)+O^(*)+2H^(*),thereby triggering the transformation of rate-limited step during the redox pathway.This biomass-derived strategy opens perspective on producing sustain-able fuels and building blocks through the RWGS reaction.
