Using catalytic oxidative absorption for H_2S removal is of great interest due to its distinct advantages. However,traditional scrubbing process faces a great limitation in the confined space. Therefore, there is an u...Using catalytic oxidative absorption for H_2S removal is of great interest due to its distinct advantages. However,traditional scrubbing process faces a great limitation in the confined space. Therefore, there is an urgent demand to develop high-efficiency process intensification technology for such a system. In this article, H_2S absorption experimental research was conducted in a rotating packed bed(RPB) reactor with ferric chelate absorbent and a mixture of N_2 and H_2S, which was used to simulate natural gas. The effects of absorbent p H value, gas–liquid ratio, gravity level of RPB, absorption temperature and character of the packing on the desulfurization efficiency were investigated. The results showed that H_2S removal efficiency could reach above 99.6% under the most of the experimental condition and above 99.9% under the optimal condition. A long-time continuous experiment was conducted to investigate the stability of the whole process combining absorption and regeneration. The result showed that the process could well realize simultaneous desulfurization and absorbent regeneration, and the H_2S removal efficiency kept relatively stable in the whole duration of 72 h. It can be clearly seen that high gravity technology desulfurization process, which is simple, high-efficiency, and space intensive, has a good prospect for industrial application of H_2S removal in confined space.展开更多
金属有机框架材料(MOF)是由金属离子或簇和有机配体通过配位键自组装形成的多孔晶体材料.MOF及其衍生物具有开放金属位点和极大的比表面积,广泛地应用在催化领域.然而,MOF材料由于存在暴露活性位点较少,传质受限或易发生不可控制的聚集...金属有机框架材料(MOF)是由金属离子或簇和有机配体通过配位键自组装形成的多孔晶体材料.MOF及其衍生物具有开放金属位点和极大的比表面积,广泛地应用在催化领域.然而,MOF材料由于存在暴露活性位点较少,传质受限或易发生不可控制的聚集等问题,会导致活性位点的损失,极大地限制了其在催化领域的应用.多级结构不仅提供更多的暴露活性位点,而且提升传质效率及稳定性.因此,设计和构造分层多级结构的MOF材料是解决上述问题的有效途径.本文制备了一种垂直自支撑式MOF多级结构材料.该多级结构材料由相互垂直自支撑式纳米片所构成;通过三维电子衍射表征显示,单个垂直自支撑式MOF多级结构颗粒显示单晶特性.因此,可以确定垂直自支撑式MOF多级结构是ZIF-67的单晶.本文也对这种结构的形成机理进行了初步探究,两种具有结构相关性ZIF在混合溶液中的相互转化是主要驱动力.这种垂直穿插的多级结构具有优异的传质/传荷能力和增强反应动力学的特性,扩展了传统多孔晶体材料的应用领域.本文通过温和的溶液硫化法,制备了保留垂直穿插结构的硫化钴,并进一步将这种垂直穿插结构的硫化钴应用在锂金属电池中.这类材料显示出多个优点:(1)具有高比表面积,提升了离子通量和传质;(2)锂离子的结合将硫化钴物种还原为钴金属颗粒;(3)垂直穿插结构引导金属沿着二维纳米片的方向沉积,避免树枝状晶体的生成.将这种垂直自支撑式硫化钴多级结构材料用作电极材料时,所组装的锂金属电池显示出有效的电流密度、高库伦效率(99%)、低成核过电位(30 mV于5 mA cm^(−2))和较好的稳定循环性(510 h).本文对于垂直穿插结构材料的设计及研究其在金属电池中的应用具有重大意义.展开更多
Oxygen reduction reaction (ORR) is an important process for the conversion and utilization of a wide range of renewable energy sources, and is critical for the shape of future energy scenario [1–10]. However, ORR is ...Oxygen reduction reaction (ORR) is an important process for the conversion and utilization of a wide range of renewable energy sources, and is critical for the shape of future energy scenario [1–10]. However, ORR is a complex four-electron transfer process and is kinetically sluggish. It is urgent to develop high-efficient electrocatalysts to solve this problem [11–15]. Up to now, precious metal-based catalysts such as Pt-based electrocatalysts have been widely studied and found to be one of the most efficient electrocatalysts for ORR. However, the high price and the small reserves limit their large-scale commercialization [10,16–23]. Therefore, in order to fulfill needs for the practical applications, it is necessary to develop low-cost electrocatalysts, also with high activity and great stability [19,24–28].展开更多
Substituent effect of metal porphyrin molecular catalysts plays a crucial role in determining the catalytic activity of oxygen electrocatalysis.Herein,substituent position effect of Co porphyrins on oxygen electrocata...Substituent effect of metal porphyrin molecular catalysts plays a crucial role in determining the catalytic activity of oxygen electrocatalysis.Herein,substituent position effect of Co porphyrins on oxygen electrocatalysis,including the oxygen reduction reaction(ORR)and the oxygen evolution reaction(OER),was investigated.Two Co porphyrins,namely 2,4,6-OMe-CoP and 3,4,5-OMe-CoP,were selected as the research objects.The ORR and OER performance was evaluated by drop-coating molecular catalysts on carbon nanotubes(CNTs).The resulted 3,4,5-OMe-CoP/CNT exhibited high bifunctional electrocatalytic activities and better long-term stability for both ORR and OER than 2,4,6-OMe-CoP/CNT.Furthermore,when applied in the Zn-air battery,3,4,5-OMe-CoP/CNT exhibited comparable performance to that with precious metal-based materials.The enhanced catalytic activity may be attributed to the improved charge transfer rate,mass transfer and hydrophilicity.This work provides an effective strategy to further enhance catalytic activity by introducing substituent position effect,which is of great importance for developing more efficient energy-related electrocatalysts.展开更多
As one of the most important families of porous materials,metal–organic frameworks(MOFs)have well-defined atomic structures.This provides ideal models for investigating and understanding the relationships between str...As one of the most important families of porous materials,metal–organic frameworks(MOFs)have well-defined atomic structures.This provides ideal models for investigating and understanding the relationships between structures and catalytic activities at the molecular level.However,the active sites on the edges of two-dimensional(2D)MOFs have rarely been studied,as they are less exposed to the surfaces.Here,for the first time,we synthesized and observed that the 2D layers could align perpendicular to the surface of a 2D zeolitic imidazolate framework L(ZIF-L)with a leaf-like morphology.Owing to this unique orientation,the active sites on the edges of the 2D crystal structure could mostly be exposed to the surfaces.Interestingly,when another layer of ZIF-L-Co was grown heteroepitaxially onto ZIF-L-Zn(ZIF-L-Zn@ZIF-L-Co),the two layers shared a common b axis but rotated by 90°in the ac plane.This demonstrated that we could control exposed facets of the 2D MOFs.The ZIF-L-Co with more exposed edge active sites exhibited high electrocatalytic activity for oxygen reduction reaction.This work provides a new concept of designing unique oriented layers in 2D MOFs to expose more edge-active sites for efficient electrocatalysis.展开更多
Constructing molecule@support composites is an attractive strategy to realize heterogeneous molecular electrocatalysis.Herein,we synthesized metal-organic framework(MOF)-supported molecular catalysts for hydrogen evol...Constructing molecule@support composites is an attractive strategy to realize heterogeneous molecular electrocatalysis.Herein,we synthesized metal-organic framework(MOF)-supported molecular catalysts for hydrogen evolution and oxygen reduction reaction(HER/ORR).Ligand exchange strategy was used to prepare molecule@support hybrids due to the same functional group.A series of hybrids were obtained using Co porphyrin(1)and different MOFs including MIL-88(Fe),MOF-5(NiCo)and UIO-66(Zr).The1@MOF-5(NiCo)had the best HER and ORR activity compared with 1@MIL-88(Fe)and 1@MOF-5(NiCo).These hybrids also exhibited tunable selectivity for ORR with four-electron process,which can be attributed to the synergistic effect of porphyrin molecules and MOFs.This work provides a possibility for molecular catalysts to improve activity of HER and tune selectivity of ORR.展开更多
Water electrolysis is considered to be an effective and promising technology to make high-purity H_(2),however,the relationship between anion species and catalytic performance of electrocatalysts is still not complete...Water electrolysis is considered to be an effective and promising technology to make high-purity H_(2),however,the relationship between anion species and catalytic performance of electrocatalysts is still not completely clear.Herein,we report an anion engineering strategy to tune electrocatalytic water oxidation activity for Co-based materials.Novel hierarchical Co-based oxide/selenide/phosphide(Co-A,A = O,Se,P)hexagrams have been chosen as model materials.Electrochemical results and theoretical calculations reveal that the electron configuration,the electrical conductivity,and the oxidation potential of Co element in Co-A hexagrams could be moderated by the substitution of P atoms,which leads to the superior OER performance.Particularly,Co-P hexagram displays a low overpotential(η = 269 mV) at j = 10 mA/cm^(2) for the oxygen evolution reaction(OER) compared to Co-O hexagram(η = 399 m V) and Co-Se hexagram(η = 347 mV).This work is of great importance in understanding coordination atoms(O,Se and P)induced electrocatalytic properties of hierarchical Co-based materials.展开更多
基金Supported by the National Natural Science Foundation of China(21406008)
文摘Using catalytic oxidative absorption for H_2S removal is of great interest due to its distinct advantages. However,traditional scrubbing process faces a great limitation in the confined space. Therefore, there is an urgent demand to develop high-efficiency process intensification technology for such a system. In this article, H_2S absorption experimental research was conducted in a rotating packed bed(RPB) reactor with ferric chelate absorbent and a mixture of N_2 and H_2S, which was used to simulate natural gas. The effects of absorbent p H value, gas–liquid ratio, gravity level of RPB, absorption temperature and character of the packing on the desulfurization efficiency were investigated. The results showed that H_2S removal efficiency could reach above 99.6% under the most of the experimental condition and above 99.9% under the optimal condition. A long-time continuous experiment was conducted to investigate the stability of the whole process combining absorption and regeneration. The result showed that the process could well realize simultaneous desulfurization and absorbent regeneration, and the H_2S removal efficiency kept relatively stable in the whole duration of 72 h. It can be clearly seen that high gravity technology desulfurization process, which is simple, high-efficiency, and space intensive, has a good prospect for industrial application of H_2S removal in confined space.
文摘金属有机框架材料(MOF)是由金属离子或簇和有机配体通过配位键自组装形成的多孔晶体材料.MOF及其衍生物具有开放金属位点和极大的比表面积,广泛地应用在催化领域.然而,MOF材料由于存在暴露活性位点较少,传质受限或易发生不可控制的聚集等问题,会导致活性位点的损失,极大地限制了其在催化领域的应用.多级结构不仅提供更多的暴露活性位点,而且提升传质效率及稳定性.因此,设计和构造分层多级结构的MOF材料是解决上述问题的有效途径.本文制备了一种垂直自支撑式MOF多级结构材料.该多级结构材料由相互垂直自支撑式纳米片所构成;通过三维电子衍射表征显示,单个垂直自支撑式MOF多级结构颗粒显示单晶特性.因此,可以确定垂直自支撑式MOF多级结构是ZIF-67的单晶.本文也对这种结构的形成机理进行了初步探究,两种具有结构相关性ZIF在混合溶液中的相互转化是主要驱动力.这种垂直穿插的多级结构具有优异的传质/传荷能力和增强反应动力学的特性,扩展了传统多孔晶体材料的应用领域.本文通过温和的溶液硫化法,制备了保留垂直穿插结构的硫化钴,并进一步将这种垂直穿插结构的硫化钴应用在锂金属电池中.这类材料显示出多个优点:(1)具有高比表面积,提升了离子通量和传质;(2)锂离子的结合将硫化钴物种还原为钴金属颗粒;(3)垂直穿插结构引导金属沿着二维纳米片的方向沉积,避免树枝状晶体的生成.将这种垂直自支撑式硫化钴多级结构材料用作电极材料时,所组装的锂金属电池显示出有效的电流密度、高库伦效率(99%)、低成核过电位(30 mV于5 mA cm^(−2))和较好的稳定循环性(510 h).本文对于垂直穿插结构材料的设计及研究其在金属电池中的应用具有重大意义.
基金supported by the National Natural Science Foundation of China(Grant No.21975148,21601118,21773146,21902099,and 21905167)the Fundamental Research Funds for the Central Universities(GK201903033 and GK202003025)+5 种基金the “Thousand Talents Program”of Chinathe Fok Ying-Tong Education Foundation for Outstanding Young Teachers in Universitythe China Postdoctoral Science Foundation(2019M650254,and 2020T130391)the Opening Fund of State Key Laboratory of Heavy Oil Processing(SKLOP202002005)the Research Fund Program of Key Laboratory of Fuel Cell Technology of Guangdong Provincethe Research Funds of Shaanxi Normal University。
文摘Oxygen reduction reaction (ORR) is an important process for the conversion and utilization of a wide range of renewable energy sources, and is critical for the shape of future energy scenario [1–10]. However, ORR is a complex four-electron transfer process and is kinetically sluggish. It is urgent to develop high-efficient electrocatalysts to solve this problem [11–15]. Up to now, precious metal-based catalysts such as Pt-based electrocatalysts have been widely studied and found to be one of the most efficient electrocatalysts for ORR. However, the high price and the small reserves limit their large-scale commercialization [10,16–23]. Therefore, in order to fulfill needs for the practical applications, it is necessary to develop low-cost electrocatalysts, also with high activity and great stability [19,24–28].
基金supported by the National Natural Science Foundation of China(22178213)the Key Research and Development Program of Shaanxi Province(2022GY-196,2022GY-201,2022GY-184)+3 种基金the Innovation Capability Support Program of Shaanxi(2023KJXX-018)the Foundation of State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering(2022-K30)the Fundamental Research Funds for the Central Universities(GK202207007,GK202309002)the Open Project of Yunnan Precious Metals Laboratory Co.,Ltd(YPML-2023050246)。
基金support from the National Natural Science Foundation of China(Nos.21808138 and 21773146)Fok Ying-Tong Education Foundation for Outstanding Young Teachers in University,Fundamental Research Funds for the Central Universities(Nos.GK202103029 and GK202103045)+2 种基金Young Talent fund of University Association for Science and Technology in Shaanxi,ChinaChina Postdoctoral Science Foundation(No.2019T120877)Research Funds of Shaanxi Normal University。
文摘Substituent effect of metal porphyrin molecular catalysts plays a crucial role in determining the catalytic activity of oxygen electrocatalysis.Herein,substituent position effect of Co porphyrins on oxygen electrocatalysis,including the oxygen reduction reaction(ORR)and the oxygen evolution reaction(OER),was investigated.Two Co porphyrins,namely 2,4,6-OMe-CoP and 3,4,5-OMe-CoP,were selected as the research objects.The ORR and OER performance was evaluated by drop-coating molecular catalysts on carbon nanotubes(CNTs).The resulted 3,4,5-OMe-CoP/CNT exhibited high bifunctional electrocatalytic activities and better long-term stability for both ORR and OER than 2,4,6-OMe-CoP/CNT.Furthermore,when applied in the Zn-air battery,3,4,5-OMe-CoP/CNT exhibited comparable performance to that with precious metal-based materials.The enhanced catalytic activity may be attributed to the improved charge transfer rate,mass transfer and hydrophilicity.This work provides an effective strategy to further enhance catalytic activity by introducing substituent position effect,which is of great importance for developing more efficient energy-related electrocatalysts.
基金the support from the National Natural Science Foundation of China(grant nos.21975148,21875149,21835002,21875140,and 21773146)the Fundamental Research Funds for the Central Universities+3 种基金the Research Funds of Shaanxi Normal University,Shanghai Natural Science Fund(no.17ZR1418600)ChEM,SPST of ShanghaiTech University(no.EM02161943)the Swedish Research Council Formas(no.2020-00831,Z.H.)the University of Calgary’s Canada First Research Excellence Fund Program,the Global Research Initiative in Sustainable Low Carbon Unconventional Resources.
文摘As one of the most important families of porous materials,metal–organic frameworks(MOFs)have well-defined atomic structures.This provides ideal models for investigating and understanding the relationships between structures and catalytic activities at the molecular level.However,the active sites on the edges of two-dimensional(2D)MOFs have rarely been studied,as they are less exposed to the surfaces.Here,for the first time,we synthesized and observed that the 2D layers could align perpendicular to the surface of a 2D zeolitic imidazolate framework L(ZIF-L)with a leaf-like morphology.Owing to this unique orientation,the active sites on the edges of the 2D crystal structure could mostly be exposed to the surfaces.Interestingly,when another layer of ZIF-L-Co was grown heteroepitaxially onto ZIF-L-Zn(ZIF-L-Zn@ZIF-L-Co),the two layers shared a common b axis but rotated by 90°in the ac plane.This demonstrated that we could control exposed facets of the 2D MOFs.The ZIF-L-Co with more exposed edge active sites exhibited high electrocatalytic activity for oxygen reduction reaction.This work provides a new concept of designing unique oriented layers in 2D MOFs to expose more edge-active sites for efficient electrocatalysis.
基金support from National Natural Science Foundation of China(Nos.21808138,22178213 and 21773146)Fundamental Research Funds for the Central Universities(No.GK202103029)Young Talent fund of University Association for Science and Technology in Shaanxi,China(No.20200602)。
文摘Constructing molecule@support composites is an attractive strategy to realize heterogeneous molecular electrocatalysis.Herein,we synthesized metal-organic framework(MOF)-supported molecular catalysts for hydrogen evolution and oxygen reduction reaction(HER/ORR).Ligand exchange strategy was used to prepare molecule@support hybrids due to the same functional group.A series of hybrids were obtained using Co porphyrin(1)and different MOFs including MIL-88(Fe),MOF-5(NiCo)and UIO-66(Zr).The1@MOF-5(NiCo)had the best HER and ORR activity compared with 1@MIL-88(Fe)and 1@MOF-5(NiCo).These hybrids also exhibited tunable selectivity for ORR with four-electron process,which can be attributed to the synergistic effect of porphyrin molecules and MOFs.This work provides a possibility for molecular catalysts to improve activity of HER and tune selectivity of ORR.
基金support from the National Natural Science Foundation of China (Nos.21808138, 21773146, 21975148 and21601118)Fok Ying-Tong Education Foundation for Outstanding Young Teachers in University+2 种基金China Postdoctoral Science Foundation (No.2019T120877)Fundamental Research Funds for the Central Universities (No.GK202103029)Young Talent Fund ofUniversity Association for Science and Technology in Shaanxi,China (No.20200602)。
文摘Water electrolysis is considered to be an effective and promising technology to make high-purity H_(2),however,the relationship between anion species and catalytic performance of electrocatalysts is still not completely clear.Herein,we report an anion engineering strategy to tune electrocatalytic water oxidation activity for Co-based materials.Novel hierarchical Co-based oxide/selenide/phosphide(Co-A,A = O,Se,P)hexagrams have been chosen as model materials.Electrochemical results and theoretical calculations reveal that the electron configuration,the electrical conductivity,and the oxidation potential of Co element in Co-A hexagrams could be moderated by the substitution of P atoms,which leads to the superior OER performance.Particularly,Co-P hexagram displays a low overpotential(η = 269 mV) at j = 10 mA/cm^(2) for the oxygen evolution reaction(OER) compared to Co-O hexagram(η = 399 m V) and Co-Se hexagram(η = 347 mV).This work is of great importance in understanding coordination atoms(O,Se and P)induced electrocatalytic properties of hierarchical Co-based materials.
