In this paper, a new anionic metal-organic framework, [In(PBPTTBA)][(CH_3)_2 NH_2](BUT-29) has been synthesized through the reaction of tetratopic acid ligand with double Lewis pyridine sites, 4,4',4'',4&#...In this paper, a new anionic metal-organic framework, [In(PBPTTBA)][(CH_3)_2 NH_2](BUT-29) has been synthesized through the reaction of tetratopic acid ligand with double Lewis pyridine sites, 4,4',4'',4'''-(4,4'-(1,4-phenylene)bis(pyridine-6,4,2-triyl)) tetrabenzoic acid(H_4 PBPTTBA) and In(NO_3)_2·5H_2O and fully characterized by single-crystal X-ray diffraction(SXRD), powder X-ray diffraction(PXRD),thermogravimetric analysis(TGA), infrared spectroscopy(IR), and elemental analysis(EA). BUT-29 can be used as an efficient adsorbent for the selective removal of organic cationic dyes in N,N0-dimethylformamide(DMF) solution. The adsorption capacities of BUT-29 toward methylene blue and crystal violet at 298 K can reach 1119 mg/g and 832 mg/g, respectively. Moreover, the adsorbed dyes can be released in the DMF solution of LiNO_3 gradually.展开更多
The fundamental insights of the reaction mechanism,especially the synergistic effect between oxygen vacancies and basic sites,are highly promising yet challenging for Ru-based catalysts during carbon dioxide(CO_(2))me...The fundamental insights of the reaction mechanism,especially the synergistic effect between oxygen vacancies and basic sites,are highly promising yet challenging for Ru-based catalysts during carbon dioxide(CO_(2))methanation.Herein,a series of Rubased catalysts were employed to study the mechanism of CO_(2) methanation.It is found that Ru/CeO_(2) catalyst exhibits a much higher CO_(2) conversion(86%)and CH4 selectivity(100%),as well as excellent stability of 30 h due to the existence of abundant oxygen vacancies and weak basic sites.Additionally,the in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and density functional theory(DFT)calculations reveal that the formate formation step dominated the hydrogenation route on Ru/CeO_(2) catalyst,and the b-HCOO^(*)could be the key intermediate due to b-HCOO^(*)is more easily hydrogenated to methane than m-HCOO^(*).The systematic study marks the significance of precise tailoring of the synergistic relationship between oxygen vacancies and basic sites for achieving the desired performance in CO_(2) methanation.展开更多
This study evaluated the site-specific effects of projected future climate conditions on the productivity of jack pine (Pinus banksiana Lamb.) plantations over the next 50 years (2011-2061). Climatic parameters as pre...This study evaluated the site-specific effects of projected future climate conditions on the productivity of jack pine (Pinus banksiana Lamb.) plantations over the next 50 years (2011-2061). Climatic parameters as predicted by the Canadian Global Climate Model in association with a regional spatial climatic model, under 3 emissions scenarios (no change (NC), B1 and A2), were used as input values to a biophysical-based site-specific height-age model that was integrated into the CROPLANNER model and associated algorithm. Plantations managed under a basic silvicultural intensity on two site qualities at each of two geographically separated sites (northeastern and northwestern Ontario, Canada) were assessed. The results indicated that the stands situated on low-to-medium quality sites at both locations were largely unaffected by the predicted increase in temperature and precipitation rates. Conversely, however, stands situated on good-to-excellent quality sites grown under the B1 and A2 scenarios experienced consequential declines in stand development rates resulting in decreases in rotational mean sizes, biomass yields, recoverable end-product volumes, and economic worth. In addition to providing a plausible range of site-specific climate change outcomes on jack pine productivity within the central portion of the species range, these results suggest that future predictions that do not account for potential climate changes effects may overes- timate merchantable productivity on the higher site qualities by approximately 15%. As demonstrated, in- corporating biophysical-based site index functions within existing forest productivity models may repre- sent a feasible approach when accounting for climate change effects on yield outcomes of boreal species.展开更多
As a typical process-intensive strategy,a tandem reaction driven by a multifunctional catalyst is a paragon of the green catalytic process.Two or more active sites are usually required and their rational spatial distr...As a typical process-intensive strategy,a tandem reaction driven by a multifunctional catalyst is a paragon of the green catalytic process.Two or more active sites are usually required and their rational spatial distribution is critical for the multi-functional catalyst to act independently or synergistically.Here,we present a simple and stepwise method to construct a trifunctional integrated catalyst simultaneously with spatially intimate acidic(phosphotungstic acid(HPW)),basic(amino)and metal(Pd nanoparticles(NPs))sites in hierarchically porous UiO-66-NH_(2).Through fine controlling the ratio of immobilized HPW and amino groups,we can easily tune its accessible acidic and basic properties,and the anchored HPW molecules can be effectively used to mediate the catalytic performance of Pd NPs and further stabilize the Pd sites.This well-designed integrated catalyst showed excellent catalytic activity and yield(>97%)towards onepot three-step Deacetalization-Knoevenagel-Hydrogenation(D-K-H)catalysis reactions owing to the synergetic catalysis and the intimate spatial arrangement of the acid,basic and metal sites.More importantly,the trifunctional catalyst could be recycled at least five times without significantly losing its activity due to the strong interaction between the MOF and the vip molecules.This work provides some important insights into the construction of multifunctional integrated catalysts,especially for the application in challenging tandem catalysis.展开更多
基金financially supported by the National Natural Science Foundation of China (NSFC, No. U1407119)
文摘In this paper, a new anionic metal-organic framework, [In(PBPTTBA)][(CH_3)_2 NH_2](BUT-29) has been synthesized through the reaction of tetratopic acid ligand with double Lewis pyridine sites, 4,4',4'',4'''-(4,4'-(1,4-phenylene)bis(pyridine-6,4,2-triyl)) tetrabenzoic acid(H_4 PBPTTBA) and In(NO_3)_2·5H_2O and fully characterized by single-crystal X-ray diffraction(SXRD), powder X-ray diffraction(PXRD),thermogravimetric analysis(TGA), infrared spectroscopy(IR), and elemental analysis(EA). BUT-29 can be used as an efficient adsorbent for the selective removal of organic cationic dyes in N,N0-dimethylformamide(DMF) solution. The adsorption capacities of BUT-29 toward methylene blue and crystal violet at 298 K can reach 1119 mg/g and 832 mg/g, respectively. Moreover, the adsorbed dyes can be released in the DMF solution of LiNO_3 gradually.
基金the National Natural Science Foundation of China(No.22102215)the Fundamental Research Funds for the Central Universities(Nos.21CX06013A and 22CX03001A)the State Key Laboratory of Heavy Oil Processing and the Key Project of China National Key R&D Plan(No.2018YFE0118200).
文摘The fundamental insights of the reaction mechanism,especially the synergistic effect between oxygen vacancies and basic sites,are highly promising yet challenging for Ru-based catalysts during carbon dioxide(CO_(2))methanation.Herein,a series of Rubased catalysts were employed to study the mechanism of CO_(2) methanation.It is found that Ru/CeO_(2) catalyst exhibits a much higher CO_(2) conversion(86%)and CH4 selectivity(100%),as well as excellent stability of 30 h due to the existence of abundant oxygen vacancies and weak basic sites.Additionally,the in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and density functional theory(DFT)calculations reveal that the formate formation step dominated the hydrogenation route on Ru/CeO_(2) catalyst,and the b-HCOO^(*)could be the key intermediate due to b-HCOO^(*)is more easily hydrogenated to methane than m-HCOO^(*).The systematic study marks the significance of precise tailoring of the synergistic relationship between oxygen vacancies and basic sites for achieving the desired performance in CO_(2) methanation.
文摘This study evaluated the site-specific effects of projected future climate conditions on the productivity of jack pine (Pinus banksiana Lamb.) plantations over the next 50 years (2011-2061). Climatic parameters as predicted by the Canadian Global Climate Model in association with a regional spatial climatic model, under 3 emissions scenarios (no change (NC), B1 and A2), were used as input values to a biophysical-based site-specific height-age model that was integrated into the CROPLANNER model and associated algorithm. Plantations managed under a basic silvicultural intensity on two site qualities at each of two geographically separated sites (northeastern and northwestern Ontario, Canada) were assessed. The results indicated that the stands situated on low-to-medium quality sites at both locations were largely unaffected by the predicted increase in temperature and precipitation rates. Conversely, however, stands situated on good-to-excellent quality sites grown under the B1 and A2 scenarios experienced consequential declines in stand development rates resulting in decreases in rotational mean sizes, biomass yields, recoverable end-product volumes, and economic worth. In addition to providing a plausible range of site-specific climate change outcomes on jack pine productivity within the central portion of the species range, these results suggest that future predictions that do not account for potential climate changes effects may overes- timate merchantable productivity on the higher site qualities by approximately 15%. As demonstrated, in- corporating biophysical-based site index functions within existing forest productivity models may repre- sent a feasible approach when accounting for climate change effects on yield outcomes of boreal species.
基金supported by the National Natural Science Foundation of China(21706199,U1662134 and 51861135313)the National Key R&D Program of China(2017YFC1103800)the NRC(Nanostructure Research Centre),Wuhan University of Technology,Wuhan,430070,PR China.
文摘As a typical process-intensive strategy,a tandem reaction driven by a multifunctional catalyst is a paragon of the green catalytic process.Two or more active sites are usually required and their rational spatial distribution is critical for the multi-functional catalyst to act independently or synergistically.Here,we present a simple and stepwise method to construct a trifunctional integrated catalyst simultaneously with spatially intimate acidic(phosphotungstic acid(HPW)),basic(amino)and metal(Pd nanoparticles(NPs))sites in hierarchically porous UiO-66-NH_(2).Through fine controlling the ratio of immobilized HPW and amino groups,we can easily tune its accessible acidic and basic properties,and the anchored HPW molecules can be effectively used to mediate the catalytic performance of Pd NPs and further stabilize the Pd sites.This well-designed integrated catalyst showed excellent catalytic activity and yield(>97%)towards onepot three-step Deacetalization-Knoevenagel-Hydrogenation(D-K-H)catalysis reactions owing to the synergetic catalysis and the intimate spatial arrangement of the acid,basic and metal sites.More importantly,the trifunctional catalyst could be recycled at least five times without significantly losing its activity due to the strong interaction between the MOF and the vip molecules.This work provides some important insights into the construction of multifunctional integrated catalysts,especially for the application in challenging tandem catalysis.
基金Supported by the National Natural Science Foundation of China(20906051)the Jiangsu Province Fundamental ResearchPlan(BK2009478)the Key Discipline Fund of Nanjing University of Technology
