The Co@NC catalysts with different morphologies were prepared by two step process,solvent control growth and pyrolysis method.The polyhedral Co@NC-67P-450 catalyst has a relatively high CoNx content and exhibits excel...The Co@NC catalysts with different morphologies were prepared by two step process,solvent control growth and pyrolysis method.The polyhedral Co@NC-67P-450 catalyst has a relatively high CoNx content and exhibits excellent phenol hydrogenation activity(conversion 96.9%)at 160℃,3 MPa,which is higher than that of leaf shaped Co@NC-67L-450 catalyst(conversion 75.4%).We demonstrated Co_(3)O_(4)was reduced to the Co^(0)during the reaction.Moreover,CoNx species contribute to the superior hydrogenation activity of phenol.The Co-based catalysts can be easily recovered through the magnetic separation and performed the high stability.展开更多
Metal organic frameworks（MOFs） are an important platform for heterogeneous catalysts.Although MOFs with a smaller particle size exhibit better catalytic performance because of less diffusion limitations,their separa...Metal organic frameworks（MOFs） are an important platform for heterogeneous catalysts.Although MOFs with a smaller particle size exhibit better catalytic performance because of less diffusion limitations,their separation and recycling after catalytic reactions are difficult.The integration of MOFs with magnetic nanoparticles could facilitate their recovery and separation.Especially,the shell thickness of the core-shell structured composites is controllable.In this study,amino-functionalized Fe3O4@Cu3（BTC）2 was fabricated by a stepwise assembly method and its catalytic performance in Knoevenagel condensation was investigated.The results demonstrated that the magnetic hybrid material exhibited a core-shell structure,with a shell thickness of about 2 00 nm.Furthermore,it not only exhibited high catalytic activity,but remarkably,it could also be easily recovered magnetically and recycled without obvious loss of catalytic efficiency after three cycles.展开更多
Using Cu-BTC prepared by hydrothermal method as precursor, carbon-based catalysts were obtained as model materials for low-temperature DeNO_x. These catalysts were characterized by X-ray diffractometry（XRD）, Raman s...Using Cu-BTC prepared by hydrothermal method as precursor, carbon-based catalysts were obtained as model materials for low-temperature DeNO_x. These catalysts were characterized by X-ray diffractometry（XRD）, Raman spectroscopy, scanning electron microscopy（SEM） and energy dispersive X-ray spectrometry（EDS）. The results showed that all carbon-based catalysts held the octahedron shape of Cu-BTC in most parts, and they mainly consisted of face-centered cubic copper. CuO_x/C exhibited excellent catalytic activity, and such catalytic activity was further improved with the introduction of Ag. The catalyst with a Cu to Ag mole ratio of 6：1 and an activated temperature of 600 °C showed the best catalytic performance, and its catalytic denitration rate reached 100% at a temperature as low as 235 °C. During the catalytic reaction process, Cu~＋ mainly played a catalytic role.展开更多
Catalysts of oxygen reduction reaction （ORR） play key roles in renewable energy technologies such as metal-air batteries and fuel cells. Despite tremendous ef- forts, highly active catalysts with low cost remain elu...Catalysts of oxygen reduction reaction （ORR） play key roles in renewable energy technologies such as metal-air batteries and fuel cells. Despite tremendous ef- forts, highly active catalysts with low cost remain elusive. This work used metal-organic frameworks to synthesize non-precious bimetallic carbon nanocomposites as efficient ORR catalysts. Although carbon-based Cu and Ni are good candidates, the hybrid nanocomposites take advantage of both metals to improve catalytic activity. The resulting molar ratio of Cu/Ni in the nanocomposites can be finely controlled by tuning the recipe of the precursors. Nanocom- posites with a series of molar ratios were produced, and they exhibited much better ORR catalytic performance than their monometallic counterparts in terms of limited current density, onset potential and half-wave potential. In addition, their extraordinary stability in alkaline is superior to that of commercially-available Pt-based materials, which adds to the appeal of the bimetallic carbon nanocomposites as ORR catalysts. Their improved performance can be attributed to the synergetic effects of Cu and Ni, and the enhancement of the carbon matrix.展开更多
Co3O4 has been considered as one kind of promising catalysts for the oxidation of CO. According to the Mars-van Krevelen mechanism, oxygen vacancies of Co3O4 play a significant role in catalytic activity. Herein, we r...Co3O4 has been considered as one kind of promising catalysts for the oxidation of CO. According to the Mars-van Krevelen mechanism, oxygen vacancies of Co3O4 play a significant role in catalytic activity. Herein, we report a novel structure-induced strategy to develop hollow Co3O4 with rich oxygen vacancies for efficient oxidation of CO. Through a reduction-oxidation pyrolysis process, the metal-organic frameworks(MOFs) precursor(i.e., ZIF-67) is transformed into H-Co3O4@H-C, in which hollow Co3O4(H-Co3O4) nanoparticles(NPs) are embedded in hollow carbon(H-C) shell.The hollow Co3O4 NPs feature rich oxygen vacancies and finish a complete conversion of CO at 130°C, which is much lower than that of solid Co3O4(the temperature of full CO conversion T100=220°C). Besides, the hollow carbon shell could also reduce the diffusion resistance during the oxidation process. Benefiting from the unique hollow structures,H-Co3O4@H-C even shows comparable activity to noble metal catalysts under high weight hourly space velocities(WHSVs)up to 240,000 mL h^–1 gcat.^–1. Furthermore, the H-Co3O4@H-C catalyst also shows good durability with only a slight decline after the reaction has been operated for 24 h.展开更多
With the aid of a postsynthetic metathesis method, an inert nitrogen-rich porphyrinic metal-organic framework can exhibit a high catalytic activity in one-pot deacetalization-Knoevenagel condensation reaction.
基金The National Natural Science Foundation of China(22102194)The Science and Technology Plan of Gansu Province(20JR10RA044)The Youth Innovation Promotion Association of CAS(2022427).
文摘The Co@NC catalysts with different morphologies were prepared by two step process,solvent control growth and pyrolysis method.The polyhedral Co@NC-67P-450 catalyst has a relatively high CoNx content and exhibits excellent phenol hydrogenation activity(conversion 96.9%)at 160℃,3 MPa,which is higher than that of leaf shaped Co@NC-67L-450 catalyst(conversion 75.4%).We demonstrated Co_(3)O_(4)was reduced to the Co^(0)during the reaction.Moreover,CoNx species contribute to the superior hydrogenation activity of phenol.The Co-based catalysts can be easily recovered through the magnetic separation and performed the high stability.
基金supported by the National Natural Science Foundation of China (21203017)the Open Fund of State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences(N-11-3)+1 种基金the Program for Liaoning Excellent Talents in University (LNET)the Fundamental Research Funds for the Central Universities (DC201502020304)~~
文摘Metal organic frameworks（MOFs） are an important platform for heterogeneous catalysts.Although MOFs with a smaller particle size exhibit better catalytic performance because of less diffusion limitations,their separation and recycling after catalytic reactions are difficult.The integration of MOFs with magnetic nanoparticles could facilitate their recovery and separation.Especially,the shell thickness of the core-shell structured composites is controllable.In this study,amino-functionalized Fe3O4@Cu3（BTC）2 was fabricated by a stepwise assembly method and its catalytic performance in Knoevenagel condensation was investigated.The results demonstrated that the magnetic hybrid material exhibited a core-shell structure,with a shell thickness of about 2 00 nm.Furthermore,it not only exhibited high catalytic activity,but remarkably,it could also be easily recovered magnetically and recycled without obvious loss of catalytic efficiency after three cycles.
基金Project(738010004)supported by the Project of Low Concentration Sulfur Dioxide Flue Gas Treatment,ChinaProject(2017GK4010)supported by the Scientific and Technological Breakthrough and Major Achievements Transformation of Strategic Emerging Industries of Hunan Province in 2017,China
文摘Using Cu-BTC prepared by hydrothermal method as precursor, carbon-based catalysts were obtained as model materials for low-temperature DeNO_x. These catalysts were characterized by X-ray diffractometry（XRD）, Raman spectroscopy, scanning electron microscopy（SEM） and energy dispersive X-ray spectrometry（EDS）. The results showed that all carbon-based catalysts held the octahedron shape of Cu-BTC in most parts, and they mainly consisted of face-centered cubic copper. CuO_x/C exhibited excellent catalytic activity, and such catalytic activity was further improved with the introduction of Ag. The catalyst with a Cu to Ag mole ratio of 6：1 and an activated temperature of 600 °C showed the best catalytic performance, and its catalytic denitration rate reached 100% at a temperature as low as 235 °C. During the catalytic reaction process, Cu~＋ mainly played a catalytic role.
基金supported by the National Natural Science Foundation of China (21671096 and 21603094)the Natural Science Foundation of Shenzhen (JCYJ20150630145302231 and JCYJ20150331101823677)the Science and Technology Innovation Foundation for the Undergraduates of SUSTech (2014S07, 2016S10 and 2016S20)
文摘Catalysts of oxygen reduction reaction （ORR） play key roles in renewable energy technologies such as metal-air batteries and fuel cells. Despite tremendous ef- forts, highly active catalysts with low cost remain elusive. This work used metal-organic frameworks to synthesize non-precious bimetallic carbon nanocomposites as efficient ORR catalysts. Although carbon-based Cu and Ni are good candidates, the hybrid nanocomposites take advantage of both metals to improve catalytic activity. The resulting molar ratio of Cu/Ni in the nanocomposites can be finely controlled by tuning the recipe of the precursors. Nanocom- posites with a series of molar ratios were produced, and they exhibited much better ORR catalytic performance than their monometallic counterparts in terms of limited current density, onset potential and half-wave potential. In addition, their extraordinary stability in alkaline is superior to that of commercially-available Pt-based materials, which adds to the appeal of the bimetallic carbon nanocomposites as ORR catalysts. Their improved performance can be attributed to the synergetic effects of Cu and Ni, and the enhancement of the carbon matrix.
基金supported by the National Natural Science Foundation of China (21825802, 21576095 and 21436005)the Fundamental Research Funds for the Central Universities (2019PY11)+2 种基金the Science and Technology Program of Guangzhou (201804020009)the State Key Laboratory of Pulp and Paper Engineering (2017ZD04 and 2018TS03)the Natural Science Foundation of Guangdong Province (2016A050502004 and 2017A030312005)
文摘Co3O4 has been considered as one kind of promising catalysts for the oxidation of CO. According to the Mars-van Krevelen mechanism, oxygen vacancies of Co3O4 play a significant role in catalytic activity. Herein, we report a novel structure-induced strategy to develop hollow Co3O4 with rich oxygen vacancies for efficient oxidation of CO. Through a reduction-oxidation pyrolysis process, the metal-organic frameworks(MOFs) precursor(i.e., ZIF-67) is transformed into H-Co3O4@H-C, in which hollow Co3O4(H-Co3O4) nanoparticles(NPs) are embedded in hollow carbon(H-C) shell.The hollow Co3O4 NPs feature rich oxygen vacancies and finish a complete conversion of CO at 130°C, which is much lower than that of solid Co3O4(the temperature of full CO conversion T100=220°C). Besides, the hollow carbon shell could also reduce the diffusion resistance during the oxidation process. Benefiting from the unique hollow structures,H-Co3O4@H-C even shows comparable activity to noble metal catalysts under high weight hourly space velocities(WHSVs)up to 240,000 mL h^–1 gcat.^–1. Furthermore, the H-Co3O4@H-C catalyst also shows good durability with only a slight decline after the reaction has been operated for 24 h.
基金Financial support of the ligand and MOFs synthesis in part by the Center for Gas Separations Relevant to Clean Energy Technologiesan Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001015+9 种基金part of the U.S. Department of Energy (DOE), ARPA-e (DE-AR0000249)DOENational Energy Technology Laboratory Award (DE-FE0026472)the Welch Foundation under award number A-1725the Welch Endowed Chair to HJZ (A-0030) for support of the structural analysesThe X-ray diffractometers, and crystallographic computing systems in the X-ray Diffraction Laboratory at the Department of Chemistry, Texas A & M University were purchased with funds provided by the National Science Foundation (CHE-9807975, CHE-0079822, CHE-0215838)The FESEM acquisition was supported by the NSF (DBI-0116835)the VP for Research Office, and the TX Eng. Exp. Station. D. Liu and C. Zhong thank the supports of Natural Science Foundation of China (21136001, 21276008)National Key Basic Research Program of China (2013CB733503)D.L. also thanks the support of China Scholarship Council (201208110375) Beijing Higher Education Young EliteTeacher Project (YETP0486)
文摘With the aid of a postsynthetic metathesis method, an inert nitrogen-rich porphyrinic metal-organic framework can exhibit a high catalytic activity in one-pot deacetalization-Knoevenagel condensation reaction.
