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Engineering asymmetric electronic structure of cobalt coordination on CoN_(3)S active sites for high performance oxygen reduction reaction
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作者 Long Chen Shuhu Yin +9 位作者 Hongbin Zeng Jia Liu Xiaofeng Xiao Xiaoyang Cheng Huan Huang Rui Huang Jian Yang Wen-Feng Lin Yan-Xia Jiang Shi-Gang Sun 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第11期494-502,共9页
The efficacy of the oxygen reduction reaction(ORR) in fuel cells can be significantly enhanced by optimizing cobalt-based catalysts,which provide a more stable alternative to iron-based catalysts.However,their perform... The efficacy of the oxygen reduction reaction(ORR) in fuel cells can be significantly enhanced by optimizing cobalt-based catalysts,which provide a more stable alternative to iron-based catalysts.However,their performance is often impeded by weak adsorption of oxygen species,leading to a 2e^(-)pathway that negatively affects fuel cell discharge efficiency.Here,we engineered a high-density cobalt active center catalyst,coordinated with nitrogen and sulfur atoms on a porous carbon substrate.Both experimental and theoretical analyses highlighted the role of sulfur atoms as electron donors,disrupting the charge symmetry of the original Co active center and promoting enhanced interaction with Co 3d orbitals.This modification improves the adsorption of oxygen and reaction intermediates during ORR,significantly reducing the production of hydrogen peroxide(H_(2)O_(2)).Remarkably,the optimized catalyst demonstrated superior fuel cell performance,with peak power densities of 1.32 W cm^(-2) in oxygen and 0.61 W cm^(-2) in air environments,respectively.A significant decrease in H_(2)O_(2) by-product accumulation was observed during the reaction process,reducing catalyst and membrane damage and consequently improving fuel cell durability.This study emphasizes the critical role of coordination symmetry in Co/N/C catalysts and proposes an effective strategy to enhance fuel cell performance. 展开更多
关键词 Fuel cells Oxygen reduction reaction Coordination symmetry CoN_(3)S H_(2)O_(2)selectivity
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Ultrathin Ti_(3)C_(2) nanowires derived from multi-layered bulks for high-performance hydrogen evolution reaction 被引量:2
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作者 Weiwei Zhao Beibei Jin +6 位作者 Longlu Wang Chengbo Ding Mengyue Jiang Tiantian Chen Shuaihang Bi Shujuan Liu Qiang Zhao 《Chinese Chemical Letters》 SCIE CAS CSCD 2022年第1期557-561,共5页
One-dimensional ultrathin nanowires(NWs)offer a great deal of promising properties for electrochemical energy storage and conversion due to their nanoscale confinement effect and high surface-to-volume ratios.It is hi... One-dimensional ultrathin nanowires(NWs)offer a great deal of promising properties for electrochemical energy storage and conversion due to their nanoscale confinement effect and high surface-to-volume ratios.It is highly desirable to precisely design and synthesize ultrathin Ti_(3)C_(2)NWs in the aspect of size,crystalline structure and composition.Here,we report a simple alkalization strategy to design the ultrathin Ti_(3)C_(2)NWs for hydrogen evolution reaction(HER)by modulating the surface-active sites.The design principle can well improve the amount of the defect sites and ion accessibility to increase the interactions between Ti_(3)C_(2)NWs and H^(*).The optimized Ti_(3)C_(2)NWs achieve an overpotential of 476 mV at the current density of 10 mA/cm^(2)and a Tafel slope of 129 mV/dec for HER catalysis,which are superior to that of Ti_(3)C_(2)nanosheets and m-Ti_(3)C_(2).It paves an avenue for the rational transformation of MXene bulks to one-dimensional NWs catalysts for HER. 展开更多
关键词 MXene Ti_(3)C_(2)nanowires Ultrathin films Chemical transformation Hydrogen evolution reaction
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Heterostructuring 2D TiO_(2) nanosheets in situ grown on Ti_(3)C_(2)T_(x) MXene to improve the electrocatalytic nitrogen reduction 被引量:1
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作者 Xiu Qian Yanjiao Wei +4 位作者 Mengjie Sun Ye Han Xiaoli Zhang Jian Tian Minhua Shao 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第7期1937-1944,共8页
In this study,TiO_(2) nanosheets(NSs)grown in situ on extremely conductive Ti_(3)C_(2)T_(x) MXene to form TiO_(2)/Ti_(3)C_(2)T_(x) MXene composites with abundant active sites are proposed to effectively achieve elec‐... In this study,TiO_(2) nanosheets(NSs)grown in situ on extremely conductive Ti_(3)C_(2)T_(x) MXene to form TiO_(2)/Ti_(3)C_(2)T_(x) MXene composites with abundant active sites are proposed to effectively achieve elec‐trocatalytic NH_(3) synthesis.Electron transfer can be promoted by Ti_(3)C_(2)T_(x) MXene with high conduc‐tivity.Meanwhile,the TiO_(2) NSs in‐situ formation can not only avoid Ti_(3)C_(2)T_(x) MXene microstacking but also enhance the surface specific area of Ti_(3)C_(2)T_(x) MXene.The TiO_(2)/Ti_(3)C_(2)T_(x) MXene catalyst reach‐es a high Faradaic efϐiciency(FE)of 44.68%at−0.75 V vs.RHE and a large NH3 yield of 44.17µg h^(-1) mg^(-1)cat.at−0.95 V,with strong electrochemical durability.15N isotopic labeling experiments imply that the N in the produced NH3 originated from the N2 of the electrolyte.DFT calculations were conducted to determine the possible NRR reaction pathways for TiO_(2)/Ti_(3)C_(2)T_(x) MXene composites.MXene catalysts combined with other materials have been rationally designed for efficient ammonia production under ambient conditions。 展开更多
关键词 ELECTROCATALYST N2 reduction reaction TiO_(2)nanosheet Ti_(3)C_(2)T_(x)MXene In‐situ growth
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一步水热合成Cu-SSZ-13分子筛选择性催化C_(3)H_(6)还原NO 被引量:5
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作者 王聪颖 周皞 +4 位作者 杨迪 张恒 赵辉爽 叶必朝 苏亚欣 《无机化学学报》 SCIE CAS CSCD 北大核心 2021年第5期853-866,共14页
采用铜胺配合物(Cu^(2+)-四乙烯五胺,Cu-TEPA)作为结构导向剂,通过一步水热法合成不同铜铝比(n_(Cu)/n_(Al))和硅铝比(n_(Si)/n_(Al))的Cu-SSZ-13分子筛催化剂,研究其在贫燃条件下丙烯选择性催化还原NO(C_(3)H_(6)-SCR)的性能。当n_(Cu)... 采用铜胺配合物(Cu^(2+)-四乙烯五胺,Cu-TEPA)作为结构导向剂,通过一步水热法合成不同铜铝比(n_(Cu)/n_(Al))和硅铝比(n_(Si)/n_(Al))的Cu-SSZ-13分子筛催化剂,研究其在贫燃条件下丙烯选择性催化还原NO(C_(3)H_(6)-SCR)的性能。当n_(Cu)/n_(Al)=2、n_(Si)/n_(Al)=6时2.0Cu-SSZ-13(6)催化剂具有最好的低温脱硝活性,200℃时NO转化率超过80%,在250~300℃可实现100%脱硝效率和~100%N_(2)选择性,同时具有较强的抗水、抗硫性能。为研究不同n_(Cu)/n_(Al)和n_(Si)/n_(Al)对催化剂物理化学特性的影响,通过X射线衍射(XRD)、扫描电子显微镜(SEM)、N_(2)吸附-脱附测试、H_(2)程序升温还原(H_(2)-TPR)、氨气程序升温脱附(NH_(3)-TPD)、紫外可见光谱(UV-Vis)等手段对样品进行表征。结果表明,2.0Cu-SSZ-13(6)具有最佳的脱硝性能,这是因为其具有最大的比表面积、最强的表面酸性和分布最多的孤立态Cu^(2+)离子。Cu-SSZ-13上丰富的酸性位可以有效促进C_(3)H_(6)和NO的吸附和活化,SSZ-13分子筛八元环中孤立的Cu^(2+)离子具有良好的氧化还原性能,是C_(3)H_(6)-SCR反应的主要活性位。随着n_(Cu)/n_(Al)的增加,孤立的Cu^(2+)离子会在分子筛表面迁移、集聚形成CuO物种,从而导致C_(3)H_(6)-SCR活性下降。 展开更多
关键词 Cu-SSZ-13 选择性催化还原 丙烯 no Cu^(2+) 硅铝比
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Cu/CeO_(2)上可见光辅助热催化合成NH_(3):H_(2)O存在下NO通过CO还原的途径
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作者 宋昕杰 范世鹏 +4 位作者 蔡泽华 杨洲 陈旬 付贤智 戴文新 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2023年第6期168-179,共12页
NH_(3)不仅是关键的工业化学原料,而且是未来可再生能源的无碳燃料和可运输的载体.目前,工业合成NH_(3)仍然以传统的Haber-Bosch反应为主,需要300-500°C的高温和20-30 MPa的压力.为克服这些缺点,研究者设计了NO-CO-H_(2)O反应体系... NH_(3)不仅是关键的工业化学原料,而且是未来可再生能源的无碳燃料和可运输的载体.目前,工业合成NH_(3)仍然以传统的Haber-Bosch反应为主,需要300-500°C的高温和20-30 MPa的压力.为克服这些缺点,研究者设计了NO-CO-H_(2)O反应体系.在该反应中,通过有毒气体CO在H_(2)O存在的条件下将NO还原成NH_(3),这是一种近乎理想的生产NH_(3)的方法.目前,已经报道了Pt/Al2O_(3)在NO-CO-H_(2)O反应中具有较高的NH_(3)选择性,但反应温度(400°C)仍然较高,不利于实际应用.因此,在低温条件下引入光照,通过光辅助热催化NO-CO-H_(2)O反应来获得NH_(3)产品,是一种极具发展潜力的方法.研究人员通过密度泛函理论(DFT)研究发现,Cu在NO还原反应中具有很高的活性和NH_(3)选择性,且Cu在水煤气(CO+H_(2)O)变换反应中具有较高的活性.CeO_(2)具有丰富氧空位同时能充当碳酸盐的储存位点,还可以起到稳定分散铜的作用.因此,本文将具有局域表面等离子体共振(LSPR)效应的金属Cu负载在具有氧空位的棒状CeO_(2)上形成Cu/CeO_(2)纳米复合材料,并研究了其催化NO-CO-H_(2)O反应性能.结果表明,Cu/CeO_(2)不仅在100-270°C下表现出较好的CO和NO去除效率,且可以选择性地催化还原NO为NH_(3).其中,5%Cu/CeO_(2)表现出最优催化活性,210°C时NO转化率为94.4%和NH_(3)选择性为66.5%.在相同温度下,可见光可以进一步提高NO转化率(97.7%)和NH_(3)选择性(69.1%).通过对NO-CO-H_(2)O反应进行分步活性测试,发现该反应的主要过程由水煤气变化反应生成活性H^(*)及其进一步与NO发生选择性催化还原反应两部分组成.准原位电子顺磁共振、原位漫反射傅立叶变换红外光谱和密度泛函理论计算表明,在Cu/CeO_(2)上NO-CO-H_(2)O的反应机理是CO首先与H_(2)O反应形成HCO_(3)^(*)中间物,然后分解成CO_(2)和活性H^(*),最后NO与活性H^(*)反应产生NH_(3).而可见光诱导Cu的LSPR效应能有效地将催化剂的光吸收范围拓宽至可见光,同时其产生的热电子能有效提高催化剂表面电子密度,从而促进了HCO_(3)^(*)分解为CO_(2)和活性H^(*);另外,在CeO_(2)上再生了氧空位(H_(2)O的活化点),进而增加了NH_(3)产量.综上,本文提供了一种在温和条件下合成NH_(3)的可行性方法,能为合成NH_(3)工艺提供一种新途径. 展开更多
关键词 no-CO-H_(2)O反应 NH_(3)合成 局域表面等离子体共振 氧空位 Cu/CeO_(2)
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Kinetics of Thermal Decomposition of Nd[(C_5H_ (10)NS_2)_3(C_ (12)H_8N_2)] in Non-Isothermal Conditions
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作者 焦宝娟 陈三平 +1 位作者 胡荣祖 高胜利 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第S1期82-85,共4页
The non-isothermal decomposition reaction of Nd[(C_5H_ 10NS_2)_3(C_ 12H_8N_2)] were carried out by means of TG-DTG and the thermal decomposition mechanism, and the associated kinetics was investigated. The kinetic par... The non-isothermal decomposition reaction of Nd[(C_5H_ 10NS_2)_3(C_ 12H_8N_2)] were carried out by means of TG-DTG and the thermal decomposition mechanism, and the associated kinetics was investigated. The kinetic parameters are obtained from an analysis of the TG-DTG curves at different heating rate by integral and differential methods. The most probable kinetic model function of the decomposition reaction is Maple Power of n=3/2, f(α)=2/3α -1/2 and the apparent activation energy E is 116.67 kJ·mol -1 and the pre-exponential factor lg[A/s -1] is 7.6891. 展开更多
关键词 Nd[(C_5H_ 10NS_2)_3(C_ 12H_8N_2)] non-isothermal kinetics TG-DTG thermal decomposition rare earths
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Novel S‐scheme 2D/2D BiOBr/g‐C_(3)N_(4)heterojunctions with enhanced photocatalytic activity 被引量:21
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作者 Bin Zhang Xiaoyun Hu +1 位作者 Enzhou Liu Jun Fan 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第9期1519-1529,共11页
The design and construction of heterojunction photocatalysts,which possess a staggered energy band structure and appropriate interfacial contact,is an effective way to achieve outstanding photocatalytic performance.In... The design and construction of heterojunction photocatalysts,which possess a staggered energy band structure and appropriate interfacial contact,is an effective way to achieve outstanding photocatalytic performance.In this study,2D/2D BiOBr/g‐C_(3)N_(4)heterojunctions were successfully obtained by a convenient in situ self‐assembly route.Under simulated sunlight irradiation,99%of RhB(10 mg·L–1,100 mL)was efficiently degraded by 1.5‐BiOBr/g‐C_(3)N_(4)within 30 min,which is better than the performance of both BiOBr and g‐C_(3)N_(4),and it has superior stability.In addition,the composite also exhibits enhanced photocatalytic activity for H2 production.The enhanced activity can be attributed to the intimate interface contact,the larger surface area,and the highly efficient separation of photoinduced electron–hole pairs.Based on the experimental results,a novel S‐scheme model was proposed to illuminate the transfer process of charge carriers.This study presents a simple way to develop novel step‐scheme photocatalysts for environmental and related applications. 展开更多
关键词 BiOBr/g‐C_(3)N_(4) 2D/2D Photocatalytic RhB degradation H_(2)evolution S‐scheme heterojunction
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Electrocatalytic hydrogen evolution performance of modified Ti_(3)C_(2)O_(2)doped with non-metal elements:A DFT study
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作者 Zhongxiao Wang Haoxiang Di +4 位作者 Rui Sun Yuting Zhu Longwei Yin Zhiwei Zhang Chengxiang Wang 《ChemPhysMater》 2022年第4期321-329,共9页
Developing highly conductive,stable,and active hydrogen evolution reaction(HER)catalysts is a critical step towards establishing the hydrogen economy.However,there are few catalysts,except for noble metals,that can me... Developing highly conductive,stable,and active hydrogen evolution reaction(HER)catalysts is a critical step towards establishing the hydrogen economy.However,there are few catalysts,except for noble metals,that can meet all the requirements.Recently,two-dimensional(2D)transition metal carbon/nitride(MXene)materials have shown excellent performance in catalysis,and have attracted wide attention from researchers.In this study,the effectiveness of non-metal element(B,C,N,P,and S)-doped Ti_(3)C_(2)O_(2)MXene in the electrocatalytic hydrogen evolution reaction was investigated using density functional theory(DFT)calculations.Non-metal atoms as elec-tron donors can provide additional electrons to the O functional group on the catalyst surface,thereby reducing charge transfer from H to O and the interaction between H and O.The Gibbs free energy(ΔG H)of non-metal element-doped Ti_(3)C_(2)O_(2)is closer to 0 than that of pristine Ti_(3)C_(2)O_(2),demonstrating better hydrogen evolution performance.Furthermore,in the hydrogen evolution path,the desorption process is more inclined to the Hey-rovsky mechanism,and doping greatly reduces the energy barrier of the reaction,thereby improving the catalytic efficiency.The present results prove that doping with non-metallic elements is an effective means of improving the catalytic activity of Ti_(3)C_(2)O_(2)for hydrogen evolution. 展开更多
关键词 Hydrogen evolution reaction non-metal DOPING Ti_(3)C_(2)O_(2) Density functional theory
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Cu_(2−x)S derived copper nanoparticles:A platform for unraveling the role of surface reconstruction in efficient electrocatalytic CO_(2)-to-C_(2)H_(4)conversion 被引量:3
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作者 Chaohua He Delong Duan +7 位作者 Jingxiang Low Yu Bai Yawen Jiang Xinyu Wang Shuangming Chen Ran Long Li Song Yujie Xiong 《Nano Research》 SCIE EI CSCD 2023年第4期4494-4498,共5页
Cu-based electrocatalysts have provoked much attention for their high activity and selectivity in carbon dioxide(CO_(2))conversion into multi-carbon hydrocarbons.However,during the electrochemical reaction,Cu catalyst... Cu-based electrocatalysts have provoked much attention for their high activity and selectivity in carbon dioxide(CO_(2))conversion into multi-carbon hydrocarbons.However,during the electrochemical reaction,Cu catalysts inevitably undergo surface reconstruction whose impact on CO_(2)conversion performance remains contentious.Here we report that polycrystalline Cu nanoparticles(denoted as Cu-s)with rich high-index facets,derived from Cu_(2−x)S through desulphurization and surface reconstruction,offer an excellent platform for investigating the role of surface reconstruction in electrocatalytic CO_(2)conversion.During the formation of Cu-s catalyst,the two stages of desulphurization and surface reconstruction can be clearly resolved by in situ X-ray absorption spectroscopy and OH−adsorption characterizations,which are well correlated with the changes in electrocatalytic performance.It turns out that the high CO_(2)conversion performance,achieved by the Cu-s catalyst(Faradic efficiency of 68.6%and partial current density of 40.8 mA/cm^(2)in H-cell toward C_(2)H_(4)production),is attributed to the increased percentage of high-index facets in Cu-s during the surface reconstruction.Furthermore,the operando electrochemical Raman spectroscopy further reveals that the conversion of the CO_(2)into the C_(2)H_(4)on Cu-s is intermediated by the production of*COCHO.Our findings manifest that the surface reconstruction is an effective method for tuning the reaction intermediate of the CO_(2)conversion toward high-value multicarbon(C2+)chemicals,and highlight the significance of in situ characterizations in enhancing the understanding of the surface structure and its role in electrocatalysis. 展开更多
关键词 CO_(2)electroreduction reaction surface reconstruction high-index facets ethylene(C_(2)H_(4)) Cu catalysts
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Simultaneous photoinduced generation of Fe^(2+) and H_2O_2 in rivers:An indicator for photo-Fenton reaction 被引量:4
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作者 Khan M.G.Mostofa Hiroshi Sakugawa 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2016年第9期34-38,共5页
The photo-Fenton reaction is a key source of the highly reactive hydroxyl radical(HOU) that is produced by the reaction of simultaneous photo-induced generation of Fe^(2+)-dissolved organic matter(DOM) with H_2... The photo-Fenton reaction is a key source of the highly reactive hydroxyl radical(HOU) that is produced by the reaction of simultaneous photo-induced generation of Fe^(2+)-dissolved organic matter(DOM) with H_2O_2 in sunlit surface waters as well as in the treatment of organic pollutants in the advanced oxidation processes(AOPs).Concentrations of both H_2O_2 and Fe^(2+)-DOM were dependent on time and total solar intensity flux,and their levels were highest in the diurnal samples collected at noon compared with the samples collected during the period before sunrise and after sunset.H_2O_2 and Fe^(2+)-DOM concentrations during monthly readings were also found higher in comparison with the diurnal samples,shortly before sunrise or after sunset.A π-electron bonding system is formed between Fe and the functional groups in DOM(Fe-DOM),through electron donation from the functional groups of DOM to an empty d-orbital of Fe.The π-electron is loosely bound and is highly susceptible to a rapid excitation upon light exposure that will provide better understanding of the formation of aqueous electrons,superoxide radical anions,H_2O_2 and finally,photo-Fenton reactions,too.Our results imply that simultaneous generation of H_2O_2 and Fe^(2+)-DOM upon sunlight exposure during the daytime is most likely to be the key photo-Fenton reaction pathway,taking place in surface waters. 展开更多
关键词 Photo-Fenton reaction Fe^(3+) Fe^(2+) Dissolved organic matter H_2O_2 Light
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Microporous Nitrogen-Rich Polymers via Ullmann Coupling Reaction for Selective Adsorption of C_(2)H_(2) over CH_(4)
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作者 Jitao Huang Qinfang Peng +9 位作者 Chulong Liu Yingxiang Ye Liangji Chen Yuanchao Lv Yisi Yang Shimin Chen Fahui Xiang Hao Zhang Zhangjing Zhang Shengchang Xiang 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2023年第5期514-520,共7页
Acetylene purification from methane is challenging in the field of porous organic polymers(POPs).Herein,we have provided one-pot Ullmann coupling reaction to synthesize a series of POPs with rich N-sites,named FJU-POP... Acetylene purification from methane is challenging in the field of porous organic polymers(POPs).Herein,we have provided one-pot Ullmann coupling reaction to synthesize a series of POPs with rich N-sites,named FJU-POP-n,wherein the low-cost and non-toxic Cu(acac)2 and environmental-friendly glycerol are employed as catalyst and solvent,respectively. 展开更多
关键词 Micro-porous materials Ullmann coupling reaction COPPER-CATALYZED Rich N-sites C_(2)H_(2)/CH_(4)separation C_(2)H_(2)/CO_(2)separation
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Density Functional Study on the Reaction Mechanism for the Reaction of Ni^+ with Ethane 被引量:2
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作者 张冬菊 刘成卜 +1 位作者 刘永军 胡海泉 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2002年第3期220-226,共7页
The mechanism of the reaction of Ni^+ (~2D) with ethane in the gas-phase wasstudied by using density functional theory. Both the B3LYP and BLYP functionals with standardall-electron basis sets are used to give the det... The mechanism of the reaction of Ni^+ (~2D) with ethane in the gas-phase wasstudied by using density functional theory. Both the B3LYP and BLYP functionals with standardall-electron basis sets are used to give the detailed information of the potential energy surface(PES) of [Ni, C_2, H_6]^+. The mechanisms forming the products CH_4 and H_2 in the reaction of Ni^+with ethane are proposed. The reductive eliminations of CH_4 and H_2 are typicaladdition-elimination reactions. Each of the two reactions consists of two elementary steps; C―C orC―H bond activations to form inserted species followed by isomerizations to form product-likeintermediate. The rate determining steps for the elimination reactions of forming CH_4 and H_2 arethe isomerizations of the inserted species rather than C―C or C―H bond activations. Theelimination reaction of forming H_2 was found to be thermodynamically favored compared to that ofCH_4. 展开更多
关键词 Ni^+ C_2H_6 reaction mechanism density func- tional theory
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Rational distribution of Ru nanodots on 2D Ti_(3−x)C_(2)T_(y)/g-C_(3)N_(4)heterostructures for boosted photocatalytic H_(2)evolution 被引量:3
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作者 Wen-Jing Yi Xin Du +7 位作者 Meng Zhang Sha-Sha Yi Rui-Hao Xia Chuan-Qi Li Yan Liu Zhong-Yi Liu Wen-Lei Zhang Xin-Zheng Yue 《Nano Research》 SCIE EI CSCD 2023年第5期6652-6660,共9页
Incorporating metal nanodots(NDs)into heterostructures for high charge separation and transfer capacities is one of the most effective strategies for improving their photocatalytic activities.However,controlling the s... Incorporating metal nanodots(NDs)into heterostructures for high charge separation and transfer capacities is one of the most effective strategies for improving their photocatalytic activities.However,controlling the space distribution of metal NDs for optimizing charge transport pathways remains a significant challenge,particularly in two-dimensional(2D)face-to-face heterostructures.Herein,we develop a simple targeted self-reduction strategy for selectively loading Ru NDs onto the Ti_(3−x)C_(2)T_(y)(TC)surface of 2D TC/g-C_(3)N_(4)(CN)heterojunction based on the reductive Ti vacancy defects creatively increased during the preparation of TC/CN by reducing calcination.Notably,the optimized Ru/TC/CN photocatalyst exhibits an outstanding H_(2)evolution rate of 3.21 mmol·g^(−1)·h^(−1)and a high apparent quantum efficiency of 30.9%at 380 nm,which is contributed by the unidirectional transfer of the photogenerated electrons from CN to Ru active sites(CN→TC→Ru)and the suppressed backflow of electrons from Ru sites to CN,as revealed by comprehensive characterizations and density functional theory(DFT)calculations.This work provides a novel strategy for synthesizing the highly efficient photocatalysts with a controllable charge transfer paths,which will boost the development of photocatalysis. 展开更多
关键词 Ru/Ti_(3−x)C_(2)T_(y)/g-C_(3)N_(4) targeted self-reduction strategy selective growth unidirectional electron migration photocatalytic H_(2)evolution
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CoP修饰Ti_(3)C_(2)T_(x)MXene纳米复合材料作为高效析氢反应电催化剂 被引量:1
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作者 孙巍 王永靖 +5 位作者 项坤 白赛帅 王海涛 邹菁 Arramel 江吉周 《物理化学学报》 SCIE CAS CSCD 北大核心 2024年第8期36-39,共4页
高效、经济和环保是电化学水分解制氢电催化剂的关键要素。二维(2D)MXene材料因其独特的物理化学性质而受到广泛关注。虽然有许多不同种类的MXene材料,但只有少数具有本征析氢反应(HER)催化活性。然而,MXene材料具有很多优点,如较大的... 高效、经济和环保是电化学水分解制氢电催化剂的关键要素。二维(2D)MXene材料因其独特的物理化学性质而受到广泛关注。虽然有许多不同种类的MXene材料,但只有少数具有本征析氢反应(HER)催化活性。然而,MXene材料具有很多优点,如较大的比表面积、高电导率和丰富的表面官能团,因此可以作为与其他物质复合的理想平台。本研究首先通过密度泛函理论(DFT)预测了CoP与Ti_(3)C_(2)T_(x)MXene(其中T_(x)=―F和―OH官能团)具有低的氢吸附自由能(ΔGH^(*))。接着,我们合成了CoP-Ti_(3)C_(2)T_(x)MXene纳米复合材料,并在0.5 mol∙L^(−1)H_(2)SO_(4)中测试了其电催化HER性能。该材料在电流密度为10 mA∙cm^(−2)时表现出了低的过电位(135 mV)和Tafel斜率为48 mV∙dec^(−1)。理论计算表明,CoP-Ti_(3)C_(2)T_(x)MXene纳米复合材料的优异电催化性能源于Ti_(3)C_(2)T_(x)的高金属导电性、良好的界面电荷转移、快速的氢吸附/解吸过程以及优化的电子结构。 展开更多
关键词 Ti_(3)C_(2)T_(x)MXene 析氢反应 COP 密度泛函理论 界面电荷转移
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用于C_(3)H_(6)/N_(2)分离的PDA@PEBA2533膜的制备
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作者 杜翠花 张茜 +2 位作者 王晓东 黄伟 周明 《化工进展》 EI CAS CSCD 北大核心 2024年第1期437-446,共10页
为回收聚丙烯制备尾气中的丙烯,采用本实验室独创的浸渍-旋转法在聚醚嵌段共聚酰胺(PEBA2533)膜表面沉积聚多巴胺(PDA)膜层制备出对C3H6具有更强亲和性的PDA@PEBA2533膜。利用扫描电子显微镜(SEM)和X射线衍射(XRD)对PDA颗粒和膜进行表... 为回收聚丙烯制备尾气中的丙烯,采用本实验室独创的浸渍-旋转法在聚醚嵌段共聚酰胺(PEBA2533)膜表面沉积聚多巴胺(PDA)膜层制备出对C3H6具有更强亲和性的PDA@PEBA2533膜。利用扫描电子显微镜(SEM)和X射线衍射(XRD)对PDA颗粒和膜进行表征。考察了PDA沉积时间对膜形貌、结构以及分离性能的影响,也考察了温度和压力等操作条件对膜分离性能的影响。探索了PDA@PEBA2533膜对不同C3H6浓度的C_(3)H_(6)/N_(2)混合气的分离效果以及膜的长时间分离稳定性。结果表明,沉积PDA于PEBA2533膜表面有效提高了膜的分离性能。当沉积时间不小于24h时,可得到连续的PDA膜层,随沉积时间的增加,膜层逐渐增厚,气体渗透速率先增大后减小,选择性持续上升,沉积24h所制备的膜分离性能最佳。增大操作温度和压力,膜对C3H6和N2的渗透速率均增大,C_(3)H_(6)/N_(2)选择性则降低。增大混合气中C3H6浓度,膜对C3H6的渗透速率和选择性均呈现先上升后下降的趋势。在所制备的分离性能最好的PDA@PEBA2533膜上,0.2MPa时,对C3H6体积分数为20%的混合气,温度从0℃提高到50℃,C3H6渗透速率从8.25GPU增加到71.42GPU,C_(3)H_(6)/N_(2)选择性从22.92降低至10.14。在130h的气体分离实验中,该膜表现出良好的稳定性。该膜与其他分离C_(3)H_(6)/N_(2)混合气膜相比具有一定的优势。 展开更多
关键词 C_(3)H_(6)/N_(2)混合气 分离 浸渍-旋转法 聚多巴胺@聚醚嵌段共聚酰胺
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无金属组分的氮化碳材料催化CO_(2)合成碳酸丙烯酯
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作者 孙校华 张学文 +2 位作者 王非 许杰 薛冰 《分子催化(中英文)》 CAS CSCD 北大核心 2024年第5期409-417,I0001,共10页
以二氰二胺为前驱体,经热聚和热剥离制备了剥离石墨相氮化碳(eg-C_(3)N_(4))材料,eg-C_(3)N_(4)再经H_(2)SO_(4)处理制得了eg-C_(3)N_(4)-S材料.采用N_(2)-吸脱附、X射线衍射、傅里叶红外光谱、X射线光电子能谱和紫外-可见漫反射等方法... 以二氰二胺为前驱体,经热聚和热剥离制备了剥离石墨相氮化碳(eg-C_(3)N_(4))材料,eg-C_(3)N_(4)再经H_(2)SO_(4)处理制得了eg-C_(3)N_(4)-S材料.采用N_(2)-吸脱附、X射线衍射、傅里叶红外光谱、X射线光电子能谱和紫外-可见漫反射等方法对材料的孔结构、化学组成等理化性质进行了表征.结果显示,热剥离有效地提高了g-C_(3)N_(4)的比表面积,而H_(2)SO_(4)处理引入了羟基.在CO_(2)和环氧丙烷环加成合成碳酸丙烯酯的催化反应中,eg-C_(3)N_(4)-S材料相较于未经H_(2)SO_(4)处理或未经热剥离的g-C_(3)N_(4)材料具有更高的催化活性.在反应压力为2.0 MPa,反应温度为140℃条件下,环氧丙烷的转化率和碳酸丙烯酯选择性分别为85%和98%. 展开更多
关键词 氮化碳 环碳酸酯 CO_(2)环加成反应
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CO_(2)/C_(3)H_(6)O在金属氧化物耦合吡咯氮生物炭表面的共/竞吸附机理研究
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作者 汪辉春 花昌豪 +4 位作者 陈萍 顾明言 龚成 邹帅 汪一 《燃料化学学报(中英文)》 EI CAS CSCD 北大核心 2024年第2期206-217,共12页
本研究采用密度泛函理论,通过比较吸附量、吸附能以及态密度和电荷差分密度的分析,探究了不同金属氧化物耦合吡咯氮生物炭(CN5@MOx,MOx=ZnO、CaO、Na2O)表面CO_(2)与C_(3)H_(6)O(CO_(2)&C_(3)H_(6)O)的吸附机理。首先从CO_(2)/C_(3)... 本研究采用密度泛函理论,通过比较吸附量、吸附能以及态密度和电荷差分密度的分析,探究了不同金属氧化物耦合吡咯氮生物炭(CN5@MOx,MOx=ZnO、CaO、Na2O)表面CO_(2)与C_(3)H_(6)O(CO_(2)&C_(3)H_(6)O)的吸附机理。首先从CO_(2)/C_(3)H_(6)O单组分方面计算了其在CN5@MOx表面吸附量和吸附能,计算结果表明,在333 K、100 kPa时CN5@Na2O表面对CO_(2)/C_(3)H_(6)O单组分吸附量分别为3.65、15.34 mmol/g,吸附能分别为-145.86、-132.47 kJ/mol,均高于CO_(2)/C_(3)H_(6)O单组分在CN5@CaO及CN5@ZnO表面吸附。得出Na2O掺杂吡咯氮生物炭对CO_(2)/C_(3)H_(6)O单组分吸附效果最优。进一步研究了CO_(2)&C_(3)H_(6)O在CN5@MOx表面共/竞吸附及机理。计算结果表明,CO_(2)&C_(3)H_(6)O在CN5@Na2O、CN5@CaO、CN5@ZnO表面吸附存在临界温度(分别为333、353、393 K),超过临界温度以后CO_(2)&C_(3)H_(6)O共存体系在CN5@MOx表面吸附量较CO_(2)/C_(3)H_(6)O单组分有所提高。CO_(2)&C_(3)H_(6)O在CN5@Na2O、 CN5@CaO、 CN5@ZnO表面吸附能分别比CO_(2)或C_(3)H_(6)O单组分吸附时至少高141.59、112.77、31.75 kJ/mol,CN5@MOx表面对CO_(2)和C_(3)H_(6)O的吸附表现为协同促进作用,且CN5@Na2O对CO_(2)&C_(3)H_(6)O共同吸附效果最佳。采用电荷差分密度和态密度分析CO_(2)&C_(3)H_(6)O在CN5@MOx表面协同吸附作用机理,得出CO_(2)的吸附作用力是通过C_(3)H_(6)O与CO_(2)的间接相互作用产生的,Na2O中Na与C_(3)H_(6)O电子云重叠,发生电荷转移,增强了两者间相互作用力,CN5@Na2O表面C_(3)H_(6)O与CN5在p轨道主要共振峰结合能较CN5@ZnO低了3.43 eV,使得C_(3)H_(6)O在CN5@Na2O表面吸附最稳定。 展开更多
关键词 吡咯氮生物炭 金属氧化物 CO_(2) C_(3)H_(6)O
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Ti_(3)C_(2)/In_(4)SnS_(8)肖特基异质结用于高效光催化生成H_(2)O_(2)和Cr(Ⅵ)还原
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作者 周彤 刘雪 +2 位作者 赵亮 乔明涛 雷琬莹 《物理化学学报》 SCIE CAS CSCD 北大核心 2024年第10期36-38,共3页
人工光合成是一种先进的技术,主要利用太阳能作为唯一驱动能源,将水和氧气转化成双氧水(H_(2)O_(2))。然而,目前常用的光催化系统的性能受制于其光吸收能力有限,载流子分离效率低以及表面反应能力弱等问题。在本文研究中,通过采用原位... 人工光合成是一种先进的技术,主要利用太阳能作为唯一驱动能源,将水和氧气转化成双氧水(H_(2)O_(2))。然而,目前常用的光催化系统的性能受制于其光吸收能力有限,载流子分离效率低以及表面反应能力弱等问题。在本文研究中,通过采用原位水热法,成功地在少层Ti_(3)C_(2)纳米片表面生长厚度为5-10 nm的立方相In_(4)SnS_(8)纳米片(Eg=2.16 eV),形成了一种具有三明治结构的Ti_(3)C_(2)/In4SnS8纳米复合材料。深入的表征结果显示此2D/2D异质结构具有紧密的界面相互作用并且形成肖特基异质结,有助于载流子快速从In_(4)SnS_(8)转移至Ti_(3)C_(2)表面。其中,7 wt%Ti_(3)C_(2)/In_(4)SnS_(8)复合材料表现出最佳的可见光催化性能,H_(2)O_(2)生成速率为1.998µmol·L^(-1)·min·1,Cr(Ⅵ)的还原速率为19.8×10^(-3)min^(-1)。通过捕获实验、气氛实验和电子顺磁共振分析,证明了H_(2)O_(2)生成的途径包括两种:一种是两步单电子还原路径,另一种是一步两电子水氧化路径。本研究为设计高效、多功能的催化体系提供了一种新的思路。 展开更多
关键词 Ti_(3)C_(2) In_(4)SnS_(8) 光催化 生成H_(2)O_(2) Cr(Ⅵ)还原
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缺陷CuAg催化剂的构筑及电催化CO_(2)还原制备C_(2+)产物
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作者 井慧芳 刘毅 +5 位作者 房强 郎学磊 郝根彦 钟达忠 李晋平 赵强 《高等学校化学学报》 SCIE EI CAS CSCD 北大核心 2024年第7期156-165,共10页
通过电化学还原Ag/Cu(OH)2构筑得到了富含缺陷位点的Ag/Cu-OH催化剂,与Ag/CuO前驱体电化学还原获得的Ag/Cu-O相比,其表现出更好的电催化二氧化碳还原反应(CO_(2)RR)制备C_(2+)产物的选择性.在H型电解槽(H-cell)中评估了催化剂的电催化性... 通过电化学还原Ag/Cu(OH)2构筑得到了富含缺陷位点的Ag/Cu-OH催化剂,与Ag/CuO前驱体电化学还原获得的Ag/Cu-O相比,其表现出更好的电催化二氧化碳还原反应(CO_(2)RR)制备C_(2+)产物的选择性.在H型电解槽(H-cell)中评估了催化剂的电催化性能,Ag2%/Cu-OH表现出比Ag2%/Cu-O高1.5倍的乙烯(C_(2)H_(4))法拉第效率(FE)和高1.3倍的C_(2+)法拉第效率.在接近实际应用的膜电极组件(MEA)中,Ag2%/Cu-OH在高达375 mA/cm^(2)的电流密度下,表现出高达56.2%的C_(2)H_(4)法拉第效率.Ag2%/Cu-OH性能的提高不仅归因于Cu和Ag之间的协同作用,还归因于具有更多的低配位Cu缺陷位点,低配位Cu有利于*CO的吸附,进一步促进了^(*)CO二聚为C_(2+)产物. 展开更多
关键词 二氧化碳还原反应 电催化 缺陷位点 乙烯产物 C_(2+)产物
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Interfacial built-in electric field and crosslinking pathways enabling WS_(2)/Ti_(3)C_(2)T_(x) heterojunction with robust sodium storage at low temperature
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作者 Jiabao Li Shaocong Tang +6 位作者 Jingjing Hao Quan Yuan Tianyi Wang Likun Pan Jinliang Li Shenbo Yang Chengyin Wang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第2期635-645,I0014,共12页
Developing efficient energy storage for sodium-ion batteries(SIBs)by creating high-performance heterojunctions and understanding their interfacial interaction at the atomic/molecular level holds promise but is also ch... Developing efficient energy storage for sodium-ion batteries(SIBs)by creating high-performance heterojunctions and understanding their interfacial interaction at the atomic/molecular level holds promise but is also challenging.Besides,sluggish reaction kinetics at low temperatures restrict the operation of SIBs in cold climates.Herein,cross-linking nanoarchitectonics of WS_(2)/Ti_(3)C_(2)T_(x) heterojunction,featuring built-in electric field(BIEF),have been developed,employing as a model to reveal the positive effect of heterojunction design and BIEF for modifying the reaction kinetics and electrochemical activity.Particularly,the theoretical analysis manifests the discrepancy in work functions leads to the electronic flow from the electron-rich Ti_(3)C_(2)T_(x) to layered WS_(2),spontaneously forming the BIEF and“ion reservoir”at the heterogeneous interface.Besides,the generation of cross-linking pathways further promotes the transportation of electrons/ions,which guarantees rapid diffusion kinetics and excellent structure coupling.Consequently,superior sodium storage performance is obtained for the WS_(2)/Ti_(3)C_(2)T_(x) heterojunction,with only 0.2%decay per cycle at 5.0 A g^(-1)(25℃)up to 1000 cycles and a high capacity of 293.5 mA h g^(-1)(0.1A g^(-1)after 100 cycles)even at-20℃.Importantly,the spontaneously formed BIEF,accompanied by“ion reservoir”,in heterojunction provides deep understandings of the correlation between structure fabricated and performance obtained. 展开更多
关键词 WS_(2)/Ti_(3)C_(2)T_(x)heterojunction Built-in electric field Ion reservoir reaction kinetics Sodium storage performance at low temperature
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