为进一步提高Mn-TiO_2/分子筛催化剂和等离子体协同的催化活性,增加CO2选择性,减少O3产量。以5A分子筛为催化剂载体,采用浸渍法并利用Ag改性制备了Ag-Mn-TiO_2/分子筛催化剂,并运用XRD、SEM、EDS和FT-IR等技术对催化剂进行了表征。在针...为进一步提高Mn-TiO_2/分子筛催化剂和等离子体协同的催化活性,增加CO2选择性,减少O3产量。以5A分子筛为催化剂载体,采用浸渍法并利用Ag改性制备了Ag-Mn-TiO_2/分子筛催化剂,并运用XRD、SEM、EDS和FT-IR等技术对催化剂进行了表征。在针-板式高压脉冲反应器中研究了Ag的负载量与焙烧温度对Ag-Mn-TiO_2/分子筛催化剂的催化活性、CO2选择性和O3的产量的影响。结果表明:掺杂Ag后,促进Mn价态向+4价转变,提高了Mn-TiO_2/分子筛催化剂活性;焙烧温度为500℃时,Ag和Mn在分子筛上分布均匀,有利于Ag和Mn氧化物晶粒成长。当脉冲电压20 k V,Ag负载量为4%时,Ag-Mn-TiO_2/分子筛催化剂的甲醛去除率达到97.6%,O3浓度为99.4 mg·m-3,CO2选择性为50.2%。展开更多
A novel,porous and doubly interpenetrated MOF（FJU-29） was synthesized and characterized by FT-IR,TGA and X-ray single-crystal/powder diffraction.FJU-29 crystallizes in monoclinic,space group C2/c with a = 22.2890（7...A novel,porous and doubly interpenetrated MOF（FJU-29） was synthesized and characterized by FT-IR,TGA and X-ray single-crystal/powder diffraction.FJU-29 crystallizes in monoclinic,space group C2/c with a = 22.2890（7）,b = 10.9175（2）,c = 21.5601（7） ？,β = 112.908（4）o,V = 4832.7（3） ？~3,Z = 8,Mr = 450.26,D_c = 1.238 g/cm^3,F（000） = 1832,μ（CuKα） = 5.885 mm^（-1）,R = 0.0585 and wR = 0.1544 for 4789 observed reflections（I 〉 2s（I））,and R = 0.0726 and wR = 0.1627 for all data.FJU-29 possesses paddle-wheel {Co_2（COO）_4} clusters bridged by bi-pyrazolate naphthalene diimide ligands（H_2NDI） and H_2BDC to from a 3D framework with a pcu-topology.The desolvated FJU-29a shows the BET surface area of 560.44 m^2·g^（-1） accompanies with discriminating uptakes in CO_2 and N_2.The adsorption selectivity determined by ideal adsorbed solution theory（IAST） indicated that FJU-29 a has high CO_2/N_2（18/85） selectivity（75.5） at 296 K and 100 kPa.The relatively high selectivity further implies that FJU-29 a is a potential material for practical flue gas purification.展开更多
FTO(Fischer-Tropsch to olefins)作为合成气制备低碳烯烃(C_(2)^(=)~C_(4)^(=))的代替路径在工业上具有重要意义。CoMnNa作为FTO反应催化剂而备受关注,但由于反应过程中CO_(2)C活性相的形成,导致CO_(2)选择性较高。引入AlO(OH)载体,制...FTO(Fischer-Tropsch to olefins)作为合成气制备低碳烯烃(C_(2)^(=)~C_(4)^(=))的代替路径在工业上具有重要意义。CoMnNa作为FTO反应催化剂而备受关注,但由于反应过程中CO_(2)C活性相的形成,导致CO_(2)选择性较高。引入AlO(OH)载体,制备了Co_(1)Mn_(1)Na/AlO(OH)催化剂,通过XRD、STEM、EDX-mapping、N_(2)吸附-脱附等温线、孔径分布曲线对催化剂进行了表征,通过H_(2)-TPR对催化剂的还原性进行了分析,并对催化剂的FTO反应性能进行了评价。结果表明,利用载体与CoMn的相互作用,降低了CoMn氧化物的还原性,有效抑制了CoMn中Co的析出及CO_(2)C的形成,减少了CoMn体系中Co和CO_(2)C活性相;在低碳烯烃选择性高达32.4%的情况下,成功将CO_(2)选择性降至10%以下。展开更多
Borocarbonitride(BCN) materials are newly developed metal-free catalytic materials exhibiting high selectivity in oxidative dehydrogenation(ODH) of alkanes. However, the in-depth understandings on the role of boron(B)...Borocarbonitride(BCN) materials are newly developed metal-free catalytic materials exhibiting high selectivity in oxidative dehydrogenation(ODH) of alkanes. However, the in-depth understandings on the role of boron(B) dopants and the intrinsic activities of –C=O and –B–OH still remain unknown.Herein, we report a series of BCN materials with regulable B content and surface oxygen functional groups via self-assembly and pyrolysis of guanine and boric acid. We found that the B/C ratio is the key parameter to determine the activity of ODH and product distribution. Among them, the high ethylbenzene conversion(~57%) and styrene selectivity(~83%) are achieved in ODH for B_(1)CN. The styrene selectivity can be improved by increasing of B/C ratio and this value reaches near 100% for B_5CN.Structural characterizations and kinetic measurements indicate that –C=O and –B–OH dual sites on BCN are real active sites of ODH reaction. The intrinsic activity of –C=O(5.556 × 10^(-4)s^(-1)) is found to be 23.7 times higher than –B–OH(0.234 × 10^(-4)s^(-1)) site. More importantly, we reveal that the deep oxidation to undesirable CO_(2) occurs on –C=O rather than –B–OH site, and B dopant in BCN materials can reduce the nucleophilicity of –C=O site to eliminate the CO_(2) emission. Overall, the present work provides a new insight on the structure–function relationship of the BCN catalytic systems.展开更多
A series of hetero-metal(Ni,Mn,and Cu)doped Co-based catalysts were prepared by a unipolar pulse electro-deposition(UPED)method and applied for the catalytic combustion of toluene.It is found that hetero-metal doping ...A series of hetero-metal(Ni,Mn,and Cu)doped Co-based catalysts were prepared by a unipolar pulse electro-deposition(UPED)method and applied for the catalytic combustion of toluene.It is found that hetero-metal doping significantly influenced the morphology and surface elemental compositions of Co-based catalysts,and the increase in the contents of Ni and Mn elements made a negative influence on the catalyst structure.H_(2)-TPR and O_(2)-TPD analysis results suggested that the hetero-metal doping enhanced the low temperature reducibility and resulted in the formation of lattice defects,which were favorable to generate more easily reducible species and facilitate the oxygen mobility,thereby improved the performance for the catalytic combustion of toluene.Especially,the Co-Cu/NF catalyst performed the best catalytic activity with the lowest toluene conversion temperature of T90 at 248℃,which should be contributed by its low-temperature reducibility,increased surface and lattice oxygen species,and high content of active Co^(3+)species promoted by the interaction of the mixed metal oxides.Moreover,the Co-Cu/NF also performed excellent catalytic stability and high selectivity to CO_(2) in the presence and absence of water vapor for the catalytic combustion of toluene for a long term.展开更多
Coal-based H2 generation has abruptly increased in recent years.The PSA-VPSA-SC process is the matured and standard framework for H2 purification and CO_(2) capture in many existing plants,including normal and vacuum ...Coal-based H2 generation has abruptly increased in recent years.The PSA-VPSA-SC process is the matured and standard framework for H2 purification and CO_(2) capture in many existing plants,including normal and vacuum pressure swing adsorption units in series(PSA-VPSA),and shallow condensation unit(SC).However,this standard process is frequently subjected to low H2 recovery ratio and high purification cost.In this work,H2-selective and C02-selective membrane units,i.e.,HM and CO_(2) M,are attempted to support the standard process and ameliorate constraints.In the beginning,HM unit is arranged after VPSA to enhance H2 recovery from the decarbonized stream,i.e.,the PSA-VPSA-SC/HM process.As a result,H2 recovery ratio can be enhanced significantly from 83%to 98%.In the following,VPSA is replaced with CO_(2) M unit to reduce investment and operation cost,i.e.,the PSA-CO_(2) M-SC/HM process.Accordingly,the specific purification cost is diminished from 33.46 to 32.02 USD·(103 m^(3) H_(2))-1,saved by 4.3%,meanwhile the construction cost is falling back and just a little higher than that for the standard process.In the end,another CO_(2) M unit is launched before PSA,i.e.,the CO_(2) M-PSA-CO_(2) M-SC/HM process,which could unbundle CO_(2) enrichment partially from H2 purification,and then save more investment and operation cost.In comparison with the standard process,this ultimate retrofitted process can be superior in all the three crucial indices,i.e.,recovery ratio,investment,and specific purification cost.On the whole,coal-based H2 generation can be ameliorated significantly through high efficient H2-selective and CO_(2)-selective membrane units.展开更多
The effects of different solvent/water coagula-tion mediums,different coagulation bath temperatures(CBT)and different coagulants on the performance,morphology and thermal stability of polysulfone mem-branes were inves...The effects of different solvent/water coagula-tion mediums,different coagulation bath temperatures(CBT)and different coagulants on the performance,morphology and thermal stability of polysulfone mem-branes were investigated.The CO_(2)/CH_(4),H_(2)/CH_(4) and H_(2)/N_(2) separation performance of the membranes were studied by gas permeation.Changing the N,N-dimethyl acetamide(DMAc)/water coagulation medium ratio from pure water to 90/10 vol%,resulted in a complete disappearance of the macrovoids throughout the polysulfone(PSf)polymeric matrix.The PSf membrane prepared in a CBT of 25℃ showed the best gas separation performance with ideal selectivities of 46.29,39.81 and 51.02 for H_(2)/CH_(4),CO_(2)/CH_(4) and H_(2)/N_(2) respectively,and permeances of 25 and 21.5 GPU for H_(2) and CO_(2) at 25℃ and 10 bar respectively.By increasing the amount of solvent in the gelation bath,the selectivities of H_(2)/CH_(4),CO_(2)/CH_(4) and H_(2)/N_(2) were dramatically reduced from 46.29,39.81 and 51.02 to 16.08,20.2 and 18.5 respectively at 25℃ and 10 bar.Reducing the CBT from 80℃ to 5℃ led to a complete elimination of macrovoids.Using methanol as a coagulant resulted in a less selective membrane compared with membranes from ethanol and water coagulants.The H_(2) and CO_(2) permeances were respectively about 3 and 9 times more than those for ethanol and water coagulants.Coated membranes were heated at different temperatures to investigate the suppression of undesirable CO_(2) plasticiza-tion.The membranes were stabilized against CO_(2) plasticization by a heat-treatment process.展开更多
By taking the functional adva ntages of both pyrazolate and carboxylate ligands,a unique dual-functional pyrazolate-carboxylate ligand acid,4-(3,6-di(pyrazol-4-yl)-9-carbazol-9-yl)benzoic acid(H3PCBA) was designed and...By taking the functional adva ntages of both pyrazolate and carboxylate ligands,a unique dual-functional pyrazolate-carboxylate ligand acid,4-(3,6-di(pyrazol-4-yl)-9-carbazol-9-yl)benzoic acid(H3PCBA) was designed and synthesized.Using it,a new Co(Ⅱ)-based metal-organic framework(MOF),Co_(3)(PCBA)_(2)(H_(2)O)_(2)(BUT-75) has been constructed.It revealed a(3,6)-connected net based on the 6-connected linear trinuclear metal node,and showed good chemical stability in a wide pH range from 3 to 12 at room temperature,as well as in boiling water.Due to the presence of rich exposed Co(Ⅱ) sites in pores,BUT-75 presented high selective CO_(2) adsorption capacity over N2 at 298 K.Simultaneously,it demonstrated fine catalytic performance for the cycloaddition of CO_(2) with epoxides into cyclic carbonates under ambient conditions.This work has not only enriched the MOF community through integrating diverse functio nalities into one ligand but also contributed a versatile platform for CO_(2) fixation,thereby pushing MOF chemistry forward by stability enhancement and application expansion.展开更多
文摘为进一步提高Mn-TiO_2/分子筛催化剂和等离子体协同的催化活性,增加CO2选择性,减少O3产量。以5A分子筛为催化剂载体,采用浸渍法并利用Ag改性制备了Ag-Mn-TiO_2/分子筛催化剂,并运用XRD、SEM、EDS和FT-IR等技术对催化剂进行了表征。在针-板式高压脉冲反应器中研究了Ag的负载量与焙烧温度对Ag-Mn-TiO_2/分子筛催化剂的催化活性、CO2选择性和O3的产量的影响。结果表明:掺杂Ag后,促进Mn价态向+4价转变,提高了Mn-TiO_2/分子筛催化剂活性;焙烧温度为500℃时,Ag和Mn在分子筛上分布均匀,有利于Ag和Mn氧化物晶粒成长。当脉冲电压20 k V,Ag负载量为4%时,Ag-Mn-TiO_2/分子筛催化剂的甲醛去除率达到97.6%,O3浓度为99.4 mg·m-3,CO2选择性为50.2%。
基金Financially supported by the National Natural Science Foundation of China(21273033,21673039 and 21573042)
文摘A novel,porous and doubly interpenetrated MOF（FJU-29） was synthesized and characterized by FT-IR,TGA and X-ray single-crystal/powder diffraction.FJU-29 crystallizes in monoclinic,space group C2/c with a = 22.2890（7）,b = 10.9175（2）,c = 21.5601（7） ？,β = 112.908（4）o,V = 4832.7（3） ？~3,Z = 8,Mr = 450.26,D_c = 1.238 g/cm^3,F（000） = 1832,μ（CuKα） = 5.885 mm^（-1）,R = 0.0585 and wR = 0.1544 for 4789 observed reflections（I 〉 2s（I））,and R = 0.0726 and wR = 0.1627 for all data.FJU-29 possesses paddle-wheel {Co_2（COO）_4} clusters bridged by bi-pyrazolate naphthalene diimide ligands（H_2NDI） and H_2BDC to from a 3D framework with a pcu-topology.The desolvated FJU-29a shows the BET surface area of 560.44 m^2·g^（-1） accompanies with discriminating uptakes in CO_2 and N_2.The adsorption selectivity determined by ideal adsorbed solution theory（IAST） indicated that FJU-29 a has high CO_2/N_2（18/85） selectivity（75.5） at 296 K and 100 kPa.The relatively high selectivity further implies that FJU-29 a is a potential material for practical flue gas purification.
文摘FTO(Fischer-Tropsch to olefins)作为合成气制备低碳烯烃(C_(2)^(=)~C_(4)^(=))的代替路径在工业上具有重要意义。CoMnNa作为FTO反应催化剂而备受关注,但由于反应过程中CO_(2)C活性相的形成,导致CO_(2)选择性较高。引入AlO(OH)载体,制备了Co_(1)Mn_(1)Na/AlO(OH)催化剂,通过XRD、STEM、EDX-mapping、N_(2)吸附-脱附等温线、孔径分布曲线对催化剂进行了表征,通过H_(2)-TPR对催化剂的还原性进行了分析,并对催化剂的FTO反应性能进行了评价。结果表明,利用载体与CoMn的相互作用,降低了CoMn氧化物的还原性,有效抑制了CoMn中Co的析出及CO_(2)C的形成,减少了CoMn体系中Co和CO_(2)C活性相;在低碳烯烃选择性高达32.4%的情况下,成功将CO_(2)选择性降至10%以下。
基金financial support from the National Natural Science Foundation of China (22072018)the Natural Science Foundation of Fujian Province of China (2021J06010)。
文摘Borocarbonitride(BCN) materials are newly developed metal-free catalytic materials exhibiting high selectivity in oxidative dehydrogenation(ODH) of alkanes. However, the in-depth understandings on the role of boron(B) dopants and the intrinsic activities of –C=O and –B–OH still remain unknown.Herein, we report a series of BCN materials with regulable B content and surface oxygen functional groups via self-assembly and pyrolysis of guanine and boric acid. We found that the B/C ratio is the key parameter to determine the activity of ODH and product distribution. Among them, the high ethylbenzene conversion(~57%) and styrene selectivity(~83%) are achieved in ODH for B_(1)CN. The styrene selectivity can be improved by increasing of B/C ratio and this value reaches near 100% for B_5CN.Structural characterizations and kinetic measurements indicate that –C=O and –B–OH dual sites on BCN are real active sites of ODH reaction. The intrinsic activity of –C=O(5.556 × 10^(-4)s^(-1)) is found to be 23.7 times higher than –B–OH(0.234 × 10^(-4)s^(-1)) site. More importantly, we reveal that the deep oxidation to undesirable CO_(2) occurs on –C=O rather than –B–OH site, and B dopant in BCN materials can reduce the nucleophilicity of –C=O site to eliminate the CO_(2) emission. Overall, the present work provides a new insight on the structure–function relationship of the BCN catalytic systems.
文摘A series of hetero-metal(Ni,Mn,and Cu)doped Co-based catalysts were prepared by a unipolar pulse electro-deposition(UPED)method and applied for the catalytic combustion of toluene.It is found that hetero-metal doping significantly influenced the morphology and surface elemental compositions of Co-based catalysts,and the increase in the contents of Ni and Mn elements made a negative influence on the catalyst structure.H_(2)-TPR and O_(2)-TPD analysis results suggested that the hetero-metal doping enhanced the low temperature reducibility and resulted in the formation of lattice defects,which were favorable to generate more easily reducible species and facilitate the oxygen mobility,thereby improved the performance for the catalytic combustion of toluene.Especially,the Co-Cu/NF catalyst performed the best catalytic activity with the lowest toluene conversion temperature of T90 at 248℃,which should be contributed by its low-temperature reducibility,increased surface and lattice oxygen species,and high content of active Co^(3+)species promoted by the interaction of the mixed metal oxides.Moreover,the Co-Cu/NF also performed excellent catalytic stability and high selectivity to CO_(2) in the presence and absence of water vapor for the catalytic combustion of toluene for a long term.
基金financial supports from the National Natural Science Foundation of China(Grant No.21978033,U1663223&21978035)China Postdoctoral Science Foundation(2019M650055)+3 种基金Liaoning Province Funds(XLYC1907063)the Changjiang Scholars Program(T2012049)the Fundamental Research Funds for the Central Universities(DUT19TD33)the Opening Project of Guangxi Key Laboratory of Petrochemical Resource Processing&Process Intensification Technology(2018K009)。
文摘Coal-based H2 generation has abruptly increased in recent years.The PSA-VPSA-SC process is the matured and standard framework for H2 purification and CO_(2) capture in many existing plants,including normal and vacuum pressure swing adsorption units in series(PSA-VPSA),and shallow condensation unit(SC).However,this standard process is frequently subjected to low H2 recovery ratio and high purification cost.In this work,H2-selective and C02-selective membrane units,i.e.,HM and CO_(2) M,are attempted to support the standard process and ameliorate constraints.In the beginning,HM unit is arranged after VPSA to enhance H2 recovery from the decarbonized stream,i.e.,the PSA-VPSA-SC/HM process.As a result,H2 recovery ratio can be enhanced significantly from 83%to 98%.In the following,VPSA is replaced with CO_(2) M unit to reduce investment and operation cost,i.e.,the PSA-CO_(2) M-SC/HM process.Accordingly,the specific purification cost is diminished from 33.46 to 32.02 USD·(103 m^(3) H_(2))-1,saved by 4.3%,meanwhile the construction cost is falling back and just a little higher than that for the standard process.In the end,another CO_(2) M unit is launched before PSA,i.e.,the CO_(2) M-PSA-CO_(2) M-SC/HM process,which could unbundle CO_(2) enrichment partially from H2 purification,and then save more investment and operation cost.In comparison with the standard process,this ultimate retrofitted process can be superior in all the three crucial indices,i.e.,recovery ratio,investment,and specific purification cost.On the whole,coal-based H2 generation can be ameliorated significantly through high efficient H2-selective and CO_(2)-selective membrane units.
基金grateful for the support provided by the Ferdowsi University of Mashhad(Grant No.35462)we are also indebted to the National Iranian Oil Refining and Distribution Company for its financial support.
文摘The effects of different solvent/water coagula-tion mediums,different coagulation bath temperatures(CBT)and different coagulants on the performance,morphology and thermal stability of polysulfone mem-branes were investigated.The CO_(2)/CH_(4),H_(2)/CH_(4) and H_(2)/N_(2) separation performance of the membranes were studied by gas permeation.Changing the N,N-dimethyl acetamide(DMAc)/water coagulation medium ratio from pure water to 90/10 vol%,resulted in a complete disappearance of the macrovoids throughout the polysulfone(PSf)polymeric matrix.The PSf membrane prepared in a CBT of 25℃ showed the best gas separation performance with ideal selectivities of 46.29,39.81 and 51.02 for H_(2)/CH_(4),CO_(2)/CH_(4) and H_(2)/N_(2) respectively,and permeances of 25 and 21.5 GPU for H_(2) and CO_(2) at 25℃ and 10 bar respectively.By increasing the amount of solvent in the gelation bath,the selectivities of H_(2)/CH_(4),CO_(2)/CH_(4) and H_(2)/N_(2) were dramatically reduced from 46.29,39.81 and 51.02 to 16.08,20.2 and 18.5 respectively at 25℃ and 10 bar.Reducing the CBT from 80℃ to 5℃ led to a complete elimination of macrovoids.Using methanol as a coagulant resulted in a less selective membrane compared with membranes from ethanol and water coagulants.The H_(2) and CO_(2) permeances were respectively about 3 and 9 times more than those for ethanol and water coagulants.Coated membranes were heated at different temperatures to investigate the suppression of undesirable CO_(2) plasticiza-tion.The membranes were stabilized against CO_(2) plasticization by a heat-treatment process.
基金financially supported by the National Natural Science Foundation of China (Nos.21771012,21601008,51621003)the Science & Technology Project of Beijing Municipal Education Committee (No.KZ201810005004)。
文摘By taking the functional adva ntages of both pyrazolate and carboxylate ligands,a unique dual-functional pyrazolate-carboxylate ligand acid,4-(3,6-di(pyrazol-4-yl)-9-carbazol-9-yl)benzoic acid(H3PCBA) was designed and synthesized.Using it,a new Co(Ⅱ)-based metal-organic framework(MOF),Co_(3)(PCBA)_(2)(H_(2)O)_(2)(BUT-75) has been constructed.It revealed a(3,6)-connected net based on the 6-connected linear trinuclear metal node,and showed good chemical stability in a wide pH range from 3 to 12 at room temperature,as well as in boiling water.Due to the presence of rich exposed Co(Ⅱ) sites in pores,BUT-75 presented high selective CO_(2) adsorption capacity over N2 at 298 K.Simultaneously,it demonstrated fine catalytic performance for the cycloaddition of CO_(2) with epoxides into cyclic carbonates under ambient conditions.This work has not only enriched the MOF community through integrating diverse functio nalities into one ligand but also contributed a versatile platform for CO_(2) fixation,thereby pushing MOF chemistry forward by stability enhancement and application expansion.
