In recent years,porous organic catalysts have been developed and become research hotspots in photo/electrocatalysis due to their inherent pores,high specific surface area,chemical and thermal stability,and diverse fun...In recent years,porous organic catalysts have been developed and become research hotspots in photo/electrocatalysis due to their inherent pores,high specific surface area,chemical and thermal stability,and diverse functional building blocks.Phenazine-linked organic catalysts,exhibited excellent conjugation,electrical conductivity,chemical,and thermal stability,could bring in N atoms with specific numbers and positions to regulate electron levels,anchor metals,and absorb near-infrared light,which expands solar energy utilization.These advantages of the phenazine-linked catalysts attracted our group and numerous researchers to conduct experimental and computational work on photo/electrocatalytic applications and mechanisms.This review summarizes the recent significant research progress,synthesis methods,photo/electrocatalytic performance,and applications of relative phenazine-linked catalysts.Furthermore,the photo/electrocatalytic mechanism was systematized and summarized by combining experiments and density functional theory calculations simultaneously.展开更多
One-pot direct conversion of cheap and abundant fructose to 2,5-diformylfuran (DFF) is highly desirable to achieve hundreds-fold value-increase and high atomic economy,yet it is still challenging due to the lack of su...One-pot direct conversion of cheap and abundant fructose to 2,5-diformylfuran (DFF) is highly desirable to achieve hundreds-fold value-increase and high atomic economy,yet it is still challenging due to the lack of suitable catalysts with cascade conversion ability.In this work,we developed a porous hybrid catalyst (i.e.PMo_(10)V_(2)@2Br-PIL) based on the assembly of polyoxometalates and porous polyionic liquids that can be applied in the one-pot conversion of fructose to DFF.The integration of PMo_(10)V_(2) with 2Br-PIL can impart both Brønsted acid and oxidation sites in the porous structure,thereby enabling the one-pot cascade conversion.As a result,PMo_(10)V_(2)@2Br-PIL demonstrated a remarkable DFF yield (95% yield),satisfying stability,recyclability and scale-up production ability (≈12.3 g in a batch experiment),demonstrating great potential for industrial production of DFF from fructose.Theoretical calculations revealed a synergistic effect of Brønsted acid sites and oxidation sites in PMo_(10)V_(2)@2Br-PIL,which promoted the one-pot conversion of fructose to DFF.This study enhances the understanding of biomass transformation over hybrid catalysts through synergetic acidic/oxidative catalysis,contributing to the development of highly active,selective,and multifunctional catalysts for one-pot biomass conversion.展开更多
Developing biomass platform compounds into high value-added chemicals is a key step in renewable resource utilization.Herein,we report porous carbon-supported Ni-ZnO nanoparticles catalyst(Ni-ZnO/AC)synthesized via lo...Developing biomass platform compounds into high value-added chemicals is a key step in renewable resource utilization.Herein,we report porous carbon-supported Ni-ZnO nanoparticles catalyst(Ni-ZnO/AC)synthesized via low-temperature coprecipitation,exhibiting excellent performance for the selective hydrogenation of 5-hydroxymethylfurfural(HMF).A linear correlation is first observed between solvent polarity(E_(T)(30))and product selectivity within both polar aprotic and protic solvent classes,suggesting that solvent properties play a vital role in directing reaction pathways.Among these,1,4-dioxane(aprotic)favors the formation of 2,5-bis(hydroxymethyl)furan(BHMF)with 97.5%selectivity,while isopropanol(iPrOH,protic)promotes 2,5-dimethylfuran production with up to 99.5%selectivity.Mechanistic investigations further reveal that beyond polarity,proton-donating ability is critical in facilitating hydrodeoxygenation.iPrOH enables a hydrogen shuttle mechanism where protons assist in hydroxyl group removal,lowering the activation barrier.In contrast,1,4-dioxane,lacking hydrogen bond donors,stabilizes BHMF and hinders further conversion.Density functional theory calculations confirm a lower activation energy in iPrOH(0.60 eV)compared to 1,4-dioxane(1.07 eV).This work offers mechanistic insights and a practical strategy for solvent-mediated control of product selectivity in biomass hydrogenation,highlighting the decisive role of solvent-catalyst-substrate interactions.展开更多
Regulating the local coordination of Fe active center can further improve the oxygen reduction reaction(ORR)performance of Fe-N-C catalyst to meet the practical application requirements of zinc-air batteries(ZABs).Her...Regulating the local coordination of Fe active center can further improve the oxygen reduction reaction(ORR)performance of Fe-N-C catalyst to meet the practical application requirements of zinc-air batteries(ZABs).Herein,carbon vacancies modified hollow porous catalysts(C-FeZ8@PDA-950)are constructed by microenvironment modulation,achieving the efficient utilization of active sites and optimization of elec-tronic structure.Density functional theory(DFT)calculations confirm that the defective-edge Fe-N_(4) sites can weaken the adsorption free energy of OH^(∗),and hinder the dissolution of Fe center,significantly accel-erating the ORR process for ZABs.The rechargeable liquid ZABs equipped with C-FeZ8@PDA-950 display high specific capacity(819.95 mAh g Zn^(−1))and excellent long-cycling life(over 500 h).Furthermore,the relevant flexible all-solid-state ZABs also display outstanding folding performance under various bending angles.This work will provide insights into optimizing the electronic structure to improve electrocatalytic performance in the energy conversion and storage area.展开更多
Novel composite material with a wide pore distribution was synthesized by an in situ technique using spent FCC catalyst as raw material. The characterization results indicated that the composite material contained 56....Novel composite material with a wide pore distribution was synthesized by an in situ technique using spent FCC catalyst as raw material. The characterization results indicated that the composite material contained 56.7% of zeolite Y and exhibited a much larger specific surface area and pore volume as well as strong hydrothermal stability. Fluid catalytic cracking(FCC) catalyst was prepared based on the composite material. The results indicated that the as-prepared catalyst possessed a unique pore structure that was advantageous to the diffusion-controlled reactions. In addition, the attrition resistance, activity and hydrothermal stability of the studied catalyst were superior to those of the reference catalyst. The catalyst also exhibited excellent nickel and vanadium passivation performance, strong bottoms upgrading selectivity, and better gasoline and coke selectivity. In comparison to the reference catalyst, the yields of the gasoline and light oil increased by 1.61 and 1.31 percentage points, respectively, and the coke yield decreased by 0.22 percentage points, and the olefin content in the produced gasoline reduced by 2.51 percentage points, with the research octane number increased by 0.7 unit.展开更多
Single-atomic Fe-Nx sites have been widely accepted as active sites for the oxygen reduction reaction(ORR),while the roles played by other symbiotic Fe moieties(such as Fe clusters)are still contentious.Synthesis of F...Single-atomic Fe-Nx sites have been widely accepted as active sites for the oxygen reduction reaction(ORR),while the roles played by other symbiotic Fe moieties(such as Fe clusters)are still contentious.Synthesis of Fe-N-C catalysts possessing both Fe-N_(x) sites and Fe clusters and investigation of their cata-lytic mechanism are essential but challenging.Herein,the controlled synthesis of a model catalyst is suc-cessfully achieved using Fe(Ⅱ)-phenanthroline(Phen)complexes as the only precursor.Through a solid-phase preparation process,Fe-Phen complexes are synthesized on the surface of silica that is used as a hard template for introducing porosity into the carbon structure.The high density of Fe centers facilitates the simultaneous generation of single atomic Fe-N_(x) sites and Fe clusters,severe aggregation of which is impeded by the silica template.The as-prepared catalyst delivers an efficient ORR performance in an alka-line environment.Combining with computational analysis,the synergistic catalytic mechanism between the Fe-Nx sites and Fe clusters is revealed that the neighboring Fe clusters can increase the adsorption energy of OOH^(*)on the Fe atom of Fe-N_(x) sites and lower the energy barrier for the formation of the OOH intermediate,thus accelerating the catalytic process.This study provides insights into the future design and synthesis of efficient Fe-N-C catalysts.展开更多
Direct synthesis of high-value-added chemicals from low-carbon molecules is of great research importance.The C(sp^(3))–H bonds in alkanes exhibit a high bond dissociation energy and a very low polarity;consequently,a...Direct synthesis of high-value-added chemicals from low-carbon molecules is of great research importance.The C(sp^(3))–H bonds in alkanes exhibit a high bond dissociation energy and a very low polarity;consequently,achieving highly selective synthesis of esters through alkoxy carbonylation in heterogeneous catalysis is a particularly challenging process.Herein,we describe the immobilization of a single-atom palladium catalyst supported by porous organic polymers for highly selective ester formation in cycloalkane carbonylation,which achieves a selectivity as high as 82% and a benzyl alcohol conversion of up to 96%.Various catalytic characterization methods,including XRD,XPS,TEM,SEM,and FTIR,indicate that palladium species are uniformly distributed in the polymer.This work suggests a promising method for the design of hybrid catalytic systems and offers meaningful insights into the development of bifunctional catalysts for selective alkoxy carbonylation.展开更多
The selective oxidation of organic sulfides is a pivotal step in the preparation of sulfoxides that can act as synthetic intermediates when preparing fine chemicals,bioactive molecules,and asymmetric catalysis ligands...The selective oxidation of organic sulfides is a pivotal step in the preparation of sulfoxides that can act as synthetic intermediates when preparing fine chemicals,bioactive molecules,and asymmetric catalysis ligands.To construct high-performance heterogeneous catalysts for sulfide-sulfoxide transformations,herein,we designed and synthesized a supramolecular porous catalyst based onε-Keggin polyoxometalates(POMs),TBA_(2)H_(2)[Zn_(4)(im)(Him)_(2)][ε-PMo_(8)VMo_(4)VIO_(40)]·3H_(2)O(1,Him=1H-imidazole).Single-crystal X-ray diffraction analysis indicates that the porous framework of 1 can be obtained via the supramolecular stacking of one-dimensional helical chains alternately linked by Zn_(4)-ε-Keggin clusters and Him ligands.During the selective oxidation of methyl phenyl sulfide to methyl phenyl sulfoxide(MPSO),compound 1 achieved a>99%yield toward MPSO and 90.3%oxidant utilization efficiency within 10 min.The corresponding turnover frequency(TOF),expressing catalytic activity,was up to 1200 h^(-1).The catalyst also demonstrated extensive substrate tolerance during catalysis,and the corresponding yields of sulfoxides were satisfactory when only 1.2 equivalents of oxidant were used.Besides this,1 can also effectively degrade a sulfur mustard simulant(2-chloroethyl ethyl sulfide)to the nontoxic product 2-chloroethyl ethyl sulfoxide within 10 min at room temperature,with an oxidant utilization efficiency of up to 94.5%.Importantly,the excellent catalytic activity of compound 1 was also proven via comparison with an analogous 3D compound 2(TOF=800 h^(-1)at full MPS conversion),TBAH_(2)[K(Him)(im)][Zn_(4)(Him)(Hip)][ε-PMo_(8)VMo_(4)VIO_(40)](Hip=4-(1H-imidazol-2-yl)-pyridine),which was covalently assembled from one-dimensional Zn_(4)-ε-Keggin POM chains and metal-organic units.Moreover,the truly heterogeneous nature of 1 and 2 was confirmed via cycling and hot-filtration experiments,and their structural stability was verified based on Fourier-transform infrared spectra and powder X-ray diffractometry(PXRD)patterns.展开更多
Heterogeneous catalysts are promising candidates for use in organic reactions due to their advantages in separation, recovery, and environment compatibility. In this work, an active porous catalyst denoted as Pd embed...Heterogeneous catalysts are promising candidates for use in organic reactions due to their advantages in separation, recovery, and environment compatibility. In this work, an active porous catalyst denoted as Pd embedded in porous carbon （Pd@CMK-3） has been prepared by a strategy involving immersion, ammonia- hydrolysis, and heating procedures. Detailed characterization of the catalyst revealed that Pd（0） and Pd（I1） species co-exist and were embedded in the matrix of the porous carbon （CMK-3）. The as-prepared catalyst has shown high activity toward Suzuki reactions. Importantly, if the reaction mixture was homogenized by two minutes of ultrasonication rather than magnetic stirring before heating, the resistance to mass transfer in the pore channels was significantly reduced. As a result, the reactions proceeded more rapidly and a four-fold increase in the turnover frequency （TOF） could be obtained. When the ultrasonication was employed throughout the entire reaction process, the conversion could also exceed 90% even without the protection of inert gas, and although the reaction temperature was lowered to 30 ℃. This work provides a method for fabricating highly active porous carbon encapsulated Pd catalysts for Suzuki reactions and proves that the problem of mass transfer in porous catalysts can be conveniently resolved by ultrasonication without any chemical modification being necessary.展开更多
MoS_(2)nanoflowers are favored for their potential in the production of elemental sulfur due to abundant surface area and good catalytic performance for reducing SO_(2).A novel synthetic strategy of porous Al_(2)O_(3)...MoS_(2)nanoflowers are favored for their potential in the production of elemental sulfur due to abundant surface area and good catalytic performance for reducing SO_(2).A novel synthetic strategy of porous Al_(2)O_(3)supported on the MoS_(2)with nanoflower structure was proposed.The effects of preparation concentration,calcination atmosphere,Al_(2)O_(3)contents on the growth of catalysts with nanoflower structure were systematically studied via X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),transmission electron microscopy(TEM),Fourier transform infrared(FTIR)spectroscopy,Brunauer–Emmett–Teller(BET).The surface area was increased to 295.502 m^(2)/g and the amount of Lewis acid on the surface of the Al_(2)O_(3)/MoS_(2)catalyst was increased by adjusting the ratio of Al/Mo.The porous and nanoflower structures of Al_(2)O_(3)/MoS_(2)catalysts promoted the sulfur selectivity without inhibiting the catalytic performance of MoS_(2).The conversion of SO_(2)and the selectivity of sulfur were 100%and 92%after 100 h life evaluation.展开更多
Five isostructural,new bimetallic ZIF precursors with various Zn/Co ratios were successfully synthesized to derive a series of N-doped porous carbons embedded with Co nanoparticles.We systematically investigated the e...Five isostructural,new bimetallic ZIF precursors with various Zn/Co ratios were successfully synthesized to derive a series of N-doped porous carbons embedded with Co nanoparticles.We systematically investigated the effect of different bimetal ratios in ZIF precursors on the electrocatalytic properties of the obtained porous carbon catalysts.展开更多
In this study,a porous hybrid catalyst with carbon-confined Ni_(2)P porous nanosheet arrays supported on nickel foam(Ni_(2)P@C NAs/NF)was developed via a one-step phosphorization of NiMOF precursor.Remarkably,the as-f...In this study,a porous hybrid catalyst with carbon-confined Ni_(2)P porous nanosheet arrays supported on nickel foam(Ni_(2)P@C NAs/NF)was developed via a one-step phosphorization of NiMOF precursor.Remarkably,the as-fabricated Ni_(2)P@C NAs/NF exhibited superior oxygen evolution reaction(OER)performance and only required a small overpotential of 243 mV to deliver a current density of 15 mA cm−2,which surpassed most reported noble-metal-free based OER catalysts working in alkaline media.Such striking results could be ascribed to the synergistic effect between the interconnected macroporous structure(facilitating mass transport and exposing rich accessible catalytic centers)and the modulated electronic states induced by electron transfer from the carbon matrix to nickel phosphide(optimizing its intrinsic electrocatalytic property).In particular,the alkaline two-electrode water electrolyser,which was assembled by simultaneously utilizing Ni_(2)P@C NAs/NF as the cathode and anode,showed considerable water-splitting activity and durability.Additionally,systematic post-electrolysis structural study confirmed the in situ formation of a γ-NiOOH film on the Ni_(2)P surface at the anode.This work provides a deep insight into the post-electrolysis structure of nickel-containing catalyst materials and would be helpful for the design of three-dimensional porous hybrid nanocatalysts.展开更多
For the first time a mathematical modelling of porous catalyst particles subject to both internal mass concentration gradients as well as temperature gradients, in endothermic or exothermic reactions has been reported...For the first time a mathematical modelling of porous catalyst particles subject to both internal mass concentration gradients as well as temperature gradients, in endothermic or exothermic reactions has been reported. This model contains a non-linear mass balance equation which is related to rate expression. This paper presents an approximate analytical method (Modified Adomian decomposition method) to solve the non-linear differential equations for chemical kinetics with diffusion effects. A simple and closed form of expressions pertaining to substrate concentration and utilization factor is presented for all value of diffusion parameters. These analytical results are compared with numerical results and found to be in good agreement.展开更多
To commercialize fuel cells and metal-air batteries, cost-effective, highly active catalysts for the oxygen reduction reaction （ORR） must be developed. Herein, we describe the development of low-cost, heteroatom （N...To commercialize fuel cells and metal-air batteries, cost-effective, highly active catalysts for the oxygen reduction reaction （ORR） must be developed. Herein, we describe the development of low-cost, heteroatom （N, P, Fe） ternary-doped, porous carbons （HDPC）. These materials are prepared by one-step pyrolysis of natural tea leaves treated with an iron salt, without any chemical and physical activation. The natural structure of the tea leaves provide a 3D hierarchical porous structure after carbonization. Moreover, heteroatom containing organic compounds in tea leaves act as precursors to functionalize the resultant carbon frameworks. In addition, we found that the polyphenols present in tea leaves act as ligands, reacting with Fe ions to form coordination compounds; these complexes acted as the precursors for Fe and N active sites. After pyrolysis, the as-prepared HDPC electrocatalysts, especially HDPC-800 （pyrolyzed at 800℃）, had more positive onsets, half-wave potentials, and higher catalytic activities for the ORR, which proceeds via a direct four-electron reaction pathway in alkaline media, similar to commercial Pt/C catalysts. Furthermore, HDPC-X also showed enhanced durability and better tolerance to methanol crossover and CO poisoning effects in comparison to commercial Pt/C, making them promising alternatives for state-of-the-art ORR electrocatalysts for electrochemical energy conversion. The method used here provides valuable guidelines for the design of high-performance ORR electrocatalysts from natural sources at the industrial scale.展开更多
Hydroformylation has been widely used in industry to manufacture high value-added aldehydes and alcohols, and is considered as the largest homogenously catalyzed process in industry. However, this process often suffer...Hydroformylation has been widely used in industry to manufacture high value-added aldehydes and alcohols, and is considered as the largest homogenously catalyzed process in industry. However, this process often suffers from complicated operation and the difficulty in catalyst recycling. It is highly desirable to develop a heterogeneous catalyst that enables the catalyst recovery without sacrificing the activity and selectivity. There are two strategies to afford such a catalyst for the hydrofromylation： immobilized catalysts on solid support and porous organic ligand （POL）-supported catalysts. In the latter, high concentration of phosphine ligands in the catalyst framework is favorable for the high dispersion of rhodium species and the formation of Rh-P multiple bonds, which endow the catalysts with high activity and stability respectively. Besides, the high linear regioselectivity could be achieved through the copolymerization of vinyl functionalized bidentate ligand （vinyl biphephos） and monodentate ligand （3vPPh3） into the catalyst framework. The newly-emerging POL-supported catalysts have great perspectives in the industrial hydroformylation.展开更多
基金supported by the Natural Science Foundation of China(52273288 and U2102211)the Natural Science Foundation of Heilongjiang Province of China(LH2021B014)the Fundamental Research Foundation for Universities of Heilongjiang Province(2021-KYYWF-0004).
文摘In recent years,porous organic catalysts have been developed and become research hotspots in photo/electrocatalysis due to their inherent pores,high specific surface area,chemical and thermal stability,and diverse functional building blocks.Phenazine-linked organic catalysts,exhibited excellent conjugation,electrical conductivity,chemical,and thermal stability,could bring in N atoms with specific numbers and positions to regulate electron levels,anchor metals,and absorb near-infrared light,which expands solar energy utilization.These advantages of the phenazine-linked catalysts attracted our group and numerous researchers to conduct experimental and computational work on photo/electrocatalytic applications and mechanisms.This review summarizes the recent significant research progress,synthesis methods,photo/electrocatalytic performance,and applications of relative phenazine-linked catalysts.Furthermore,the photo/electrocatalytic mechanism was systematized and summarized by combining experiments and density functional theory calculations simultaneously.
基金financially supported by the National Natural Science Foundation of China(No.21871125,22475074,22171139 and 22201116)Natural Science Foundation of Guangdong Province(No.2023B1515020076)+2 种基金Natural Science Foundation of Shandong Province(No.ZR2022QB066 and ZR2023MB018)Dongying City School Cooperation Fund Key Project(SXHZ-2023-02-15)college Student Innovation and Entrepreneurship Training Plan of Liaocheng University(cxcy089).
文摘One-pot direct conversion of cheap and abundant fructose to 2,5-diformylfuran (DFF) is highly desirable to achieve hundreds-fold value-increase and high atomic economy,yet it is still challenging due to the lack of suitable catalysts with cascade conversion ability.In this work,we developed a porous hybrid catalyst (i.e.PMo_(10)V_(2)@2Br-PIL) based on the assembly of polyoxometalates and porous polyionic liquids that can be applied in the one-pot conversion of fructose to DFF.The integration of PMo_(10)V_(2) with 2Br-PIL can impart both Brønsted acid and oxidation sites in the porous structure,thereby enabling the one-pot cascade conversion.As a result,PMo_(10)V_(2)@2Br-PIL demonstrated a remarkable DFF yield (95% yield),satisfying stability,recyclability and scale-up production ability (≈12.3 g in a batch experiment),demonstrating great potential for industrial production of DFF from fructose.Theoretical calculations revealed a synergistic effect of Brønsted acid sites and oxidation sites in PMo_(10)V_(2)@2Br-PIL,which promoted the one-pot conversion of fructose to DFF.This study enhances the understanding of biomass transformation over hybrid catalysts through synergetic acidic/oxidative catalysis,contributing to the development of highly active,selective,and multifunctional catalysts for one-pot biomass conversion.
基金the National Nature Science Foundation of China for Excellent Young Scientists Fund(32222058)Fundamental Research Foundation of CAF(CAFYBB2022QB001).
文摘Developing biomass platform compounds into high value-added chemicals is a key step in renewable resource utilization.Herein,we report porous carbon-supported Ni-ZnO nanoparticles catalyst(Ni-ZnO/AC)synthesized via low-temperature coprecipitation,exhibiting excellent performance for the selective hydrogenation of 5-hydroxymethylfurfural(HMF).A linear correlation is first observed between solvent polarity(E_(T)(30))and product selectivity within both polar aprotic and protic solvent classes,suggesting that solvent properties play a vital role in directing reaction pathways.Among these,1,4-dioxane(aprotic)favors the formation of 2,5-bis(hydroxymethyl)furan(BHMF)with 97.5%selectivity,while isopropanol(iPrOH,protic)promotes 2,5-dimethylfuran production with up to 99.5%selectivity.Mechanistic investigations further reveal that beyond polarity,proton-donating ability is critical in facilitating hydrodeoxygenation.iPrOH enables a hydrogen shuttle mechanism where protons assist in hydroxyl group removal,lowering the activation barrier.In contrast,1,4-dioxane,lacking hydrogen bond donors,stabilizes BHMF and hinders further conversion.Density functional theory calculations confirm a lower activation energy in iPrOH(0.60 eV)compared to 1,4-dioxane(1.07 eV).This work offers mechanistic insights and a practical strategy for solvent-mediated control of product selectivity in biomass hydrogenation,highlighting the decisive role of solvent-catalyst-substrate interactions.
基金supported by the National Natural Science Foundation of China(Nos.22078028,21978026,22209016)the International Scientific and Technological Cooperation Program of Changzhou(No.CZ20220028)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX23_3025).
文摘Regulating the local coordination of Fe active center can further improve the oxygen reduction reaction(ORR)performance of Fe-N-C catalyst to meet the practical application requirements of zinc-air batteries(ZABs).Herein,carbon vacancies modified hollow porous catalysts(C-FeZ8@PDA-950)are constructed by microenvironment modulation,achieving the efficient utilization of active sites and optimization of elec-tronic structure.Density functional theory(DFT)calculations confirm that the defective-edge Fe-N_(4) sites can weaken the adsorption free energy of OH^(∗),and hinder the dissolution of Fe center,significantly accel-erating the ORR process for ZABs.The rechargeable liquid ZABs equipped with C-FeZ8@PDA-950 display high specific capacity(819.95 mAh g Zn^(−1))and excellent long-cycling life(over 500 h).Furthermore,the relevant flexible all-solid-state ZABs also display outstanding folding performance under various bending angles.This work will provide insights into optimizing the electronic structure to improve electrocatalytic performance in the energy conversion and storage area.
基金provided by the National Natural Science Foundation of China(No.21371055)the Hunan provincial Natural Science Foundation of China(No.11JJ2008)the Hunan provincial Colleges and Universities Innovation Platform Open Fund Project(No.15K049)
文摘Novel composite material with a wide pore distribution was synthesized by an in situ technique using spent FCC catalyst as raw material. The characterization results indicated that the composite material contained 56.7% of zeolite Y and exhibited a much larger specific surface area and pore volume as well as strong hydrothermal stability. Fluid catalytic cracking(FCC) catalyst was prepared based on the composite material. The results indicated that the as-prepared catalyst possessed a unique pore structure that was advantageous to the diffusion-controlled reactions. In addition, the attrition resistance, activity and hydrothermal stability of the studied catalyst were superior to those of the reference catalyst. The catalyst also exhibited excellent nickel and vanadium passivation performance, strong bottoms upgrading selectivity, and better gasoline and coke selectivity. In comparison to the reference catalyst, the yields of the gasoline and light oil increased by 1.61 and 1.31 percentage points, respectively, and the coke yield decreased by 0.22 percentage points, and the olefin content in the produced gasoline reduced by 2.51 percentage points, with the research octane number increased by 0.7 unit.
基金upported by the National Natural Science Foundation of China(Grant no.21875285,22171288,22005340)the Key Research and Development Projects of Shandong Province(2019JZZY010331)+1 种基金the Natural Science Foundation of Shandong Province(ZR2020MB017)the PetroChina Innovation Foundation(2019D-5007-0411).
文摘Single-atomic Fe-Nx sites have been widely accepted as active sites for the oxygen reduction reaction(ORR),while the roles played by other symbiotic Fe moieties(such as Fe clusters)are still contentious.Synthesis of Fe-N-C catalysts possessing both Fe-N_(x) sites and Fe clusters and investigation of their cata-lytic mechanism are essential but challenging.Herein,the controlled synthesis of a model catalyst is suc-cessfully achieved using Fe(Ⅱ)-phenanthroline(Phen)complexes as the only precursor.Through a solid-phase preparation process,Fe-Phen complexes are synthesized on the surface of silica that is used as a hard template for introducing porosity into the carbon structure.The high density of Fe centers facilitates the simultaneous generation of single atomic Fe-N_(x) sites and Fe clusters,severe aggregation of which is impeded by the silica template.The as-prepared catalyst delivers an efficient ORR performance in an alka-line environment.Combining with computational analysis,the synergistic catalytic mechanism between the Fe-Nx sites and Fe clusters is revealed that the neighboring Fe clusters can increase the adsorption energy of OOH^(*)on the Fe atom of Fe-N_(x) sites and lower the energy barrier for the formation of the OOH intermediate,thus accelerating the catalytic process.This study provides insights into the future design and synthesis of efficient Fe-N-C catalysts.
基金supported by the National Natural Science Foundation of China (U22A20393,22202216)the Lanzhou Institute of Chemical Physics (E40199SR)。
文摘Direct synthesis of high-value-added chemicals from low-carbon molecules is of great research importance.The C(sp^(3))–H bonds in alkanes exhibit a high bond dissociation energy and a very low polarity;consequently,achieving highly selective synthesis of esters through alkoxy carbonylation in heterogeneous catalysis is a particularly challenging process.Herein,we describe the immobilization of a single-atom palladium catalyst supported by porous organic polymers for highly selective ester formation in cycloalkane carbonylation,which achieves a selectivity as high as 82% and a benzyl alcohol conversion of up to 96%.Various catalytic characterization methods,including XRD,XPS,TEM,SEM,and FTIR,indicate that palladium species are uniformly distributed in the polymer.This work suggests a promising method for the design of hybrid catalytic systems and offers meaningful insights into the development of bifunctional catalysts for selective alkoxy carbonylation.
基金supported by the National Natural Science Foundation of China(21371027,20901013)the Natural Science Foundation of Liaoning Province(2015020232)the Fundamental Research Funds for the Central Universities(DUT19LK01,DUT15LN18).
文摘The selective oxidation of organic sulfides is a pivotal step in the preparation of sulfoxides that can act as synthetic intermediates when preparing fine chemicals,bioactive molecules,and asymmetric catalysis ligands.To construct high-performance heterogeneous catalysts for sulfide-sulfoxide transformations,herein,we designed and synthesized a supramolecular porous catalyst based onε-Keggin polyoxometalates(POMs),TBA_(2)H_(2)[Zn_(4)(im)(Him)_(2)][ε-PMo_(8)VMo_(4)VIO_(40)]·3H_(2)O(1,Him=1H-imidazole).Single-crystal X-ray diffraction analysis indicates that the porous framework of 1 can be obtained via the supramolecular stacking of one-dimensional helical chains alternately linked by Zn_(4)-ε-Keggin clusters and Him ligands.During the selective oxidation of methyl phenyl sulfide to methyl phenyl sulfoxide(MPSO),compound 1 achieved a>99%yield toward MPSO and 90.3%oxidant utilization efficiency within 10 min.The corresponding turnover frequency(TOF),expressing catalytic activity,was up to 1200 h^(-1).The catalyst also demonstrated extensive substrate tolerance during catalysis,and the corresponding yields of sulfoxides were satisfactory when only 1.2 equivalents of oxidant were used.Besides this,1 can also effectively degrade a sulfur mustard simulant(2-chloroethyl ethyl sulfide)to the nontoxic product 2-chloroethyl ethyl sulfoxide within 10 min at room temperature,with an oxidant utilization efficiency of up to 94.5%.Importantly,the excellent catalytic activity of compound 1 was also proven via comparison with an analogous 3D compound 2(TOF=800 h^(-1)at full MPS conversion),TBAH_(2)[K(Him)(im)][Zn_(4)(Him)(Hip)][ε-PMo_(8)VMo_(4)VIO_(40)](Hip=4-(1H-imidazol-2-yl)-pyridine),which was covalently assembled from one-dimensional Zn_(4)-ε-Keggin POM chains and metal-organic units.Moreover,the truly heterogeneous nature of 1 and 2 was confirmed via cycling and hot-filtration experiments,and their structural stability was verified based on Fourier-transform infrared spectra and powder X-ray diffractometry(PXRD)patterns.
文摘Heterogeneous catalysts are promising candidates for use in organic reactions due to their advantages in separation, recovery, and environment compatibility. In this work, an active porous catalyst denoted as Pd embedded in porous carbon （Pd@CMK-3） has been prepared by a strategy involving immersion, ammonia- hydrolysis, and heating procedures. Detailed characterization of the catalyst revealed that Pd（0） and Pd（I1） species co-exist and were embedded in the matrix of the porous carbon （CMK-3）. The as-prepared catalyst has shown high activity toward Suzuki reactions. Importantly, if the reaction mixture was homogenized by two minutes of ultrasonication rather than magnetic stirring before heating, the resistance to mass transfer in the pore channels was significantly reduced. As a result, the reactions proceeded more rapidly and a four-fold increase in the turnover frequency （TOF） could be obtained. When the ultrasonication was employed throughout the entire reaction process, the conversion could also exceed 90% even without the protection of inert gas, and although the reaction temperature was lowered to 30 ℃. This work provides a method for fabricating highly active porous carbon encapsulated Pd catalysts for Suzuki reactions and proves that the problem of mass transfer in porous catalysts can be conveniently resolved by ultrasonication without any chemical modification being necessary.
基金the National Natural Science Fund for Distinguished Young Scholars of China(No.22025803).
文摘MoS_(2)nanoflowers are favored for their potential in the production of elemental sulfur due to abundant surface area and good catalytic performance for reducing SO_(2).A novel synthetic strategy of porous Al_(2)O_(3)supported on the MoS_(2)with nanoflower structure was proposed.The effects of preparation concentration,calcination atmosphere,Al_(2)O_(3)contents on the growth of catalysts with nanoflower structure were systematically studied via X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),transmission electron microscopy(TEM),Fourier transform infrared(FTIR)spectroscopy,Brunauer–Emmett–Teller(BET).The surface area was increased to 295.502 m^(2)/g and the amount of Lewis acid on the surface of the Al_(2)O_(3)/MoS_(2)catalyst was increased by adjusting the ratio of Al/Mo.The porous and nanoflower structures of Al_(2)O_(3)/MoS_(2)catalysts promoted the sulfur selectivity without inhibiting the catalytic performance of MoS_(2).The conversion of SO_(2)and the selectivity of sulfur were 100%and 92%after 100 h life evaluation.
基金financially supported by the National Natural Science Foundation of China(21571076 and 21571079)the“111”project(BP0719036).
文摘Five isostructural,new bimetallic ZIF precursors with various Zn/Co ratios were successfully synthesized to derive a series of N-doped porous carbons embedded with Co nanoparticles.We systematically investigated the effect of different bimetal ratios in ZIF precursors on the electrocatalytic properties of the obtained porous carbon catalysts.
基金supported by the National Key Research and Development Program of China(2017YFA0206500 and 2017YFA0206801)the National Natural Science Foundation of China(21671163,21773190,21721001,and 21931009).
文摘In this study,a porous hybrid catalyst with carbon-confined Ni_(2)P porous nanosheet arrays supported on nickel foam(Ni_(2)P@C NAs/NF)was developed via a one-step phosphorization of NiMOF precursor.Remarkably,the as-fabricated Ni_(2)P@C NAs/NF exhibited superior oxygen evolution reaction(OER)performance and only required a small overpotential of 243 mV to deliver a current density of 15 mA cm−2,which surpassed most reported noble-metal-free based OER catalysts working in alkaline media.Such striking results could be ascribed to the synergistic effect between the interconnected macroporous structure(facilitating mass transport and exposing rich accessible catalytic centers)and the modulated electronic states induced by electron transfer from the carbon matrix to nickel phosphide(optimizing its intrinsic electrocatalytic property).In particular,the alkaline two-electrode water electrolyser,which was assembled by simultaneously utilizing Ni_(2)P@C NAs/NF as the cathode and anode,showed considerable water-splitting activity and durability.Additionally,systematic post-electrolysis structural study confirmed the in situ formation of a γ-NiOOH film on the Ni_(2)P surface at the anode.This work provides a deep insight into the post-electrolysis structure of nickel-containing catalyst materials and would be helpful for the design of three-dimensional porous hybrid nanocatalysts.
文摘For the first time a mathematical modelling of porous catalyst particles subject to both internal mass concentration gradients as well as temperature gradients, in endothermic or exothermic reactions has been reported. This model contains a non-linear mass balance equation which is related to rate expression. This paper presents an approximate analytical method (Modified Adomian decomposition method) to solve the non-linear differential equations for chemical kinetics with diffusion effects. A simple and closed form of expressions pertaining to substrate concentration and utilization factor is presented for all value of diffusion parameters. These analytical results are compared with numerical results and found to be in good agreement.
基金Acknowledgements The authors thank the financial support by the National Natural Science Foundation of China （No. 51273008 and 51473008）, the National High-Tech Research and Development Program （No. 2012AA030305）, the National Basic Research Program （No. 2012CB933200）, and NSF （No. CMMI-1400274 and AIR-IIP-1343270）.
文摘To commercialize fuel cells and metal-air batteries, cost-effective, highly active catalysts for the oxygen reduction reaction （ORR） must be developed. Herein, we describe the development of low-cost, heteroatom （N, P, Fe） ternary-doped, porous carbons （HDPC）. These materials are prepared by one-step pyrolysis of natural tea leaves treated with an iron salt, without any chemical and physical activation. The natural structure of the tea leaves provide a 3D hierarchical porous structure after carbonization. Moreover, heteroatom containing organic compounds in tea leaves act as precursors to functionalize the resultant carbon frameworks. In addition, we found that the polyphenols present in tea leaves act as ligands, reacting with Fe ions to form coordination compounds; these complexes acted as the precursors for Fe and N active sites. After pyrolysis, the as-prepared HDPC electrocatalysts, especially HDPC-800 （pyrolyzed at 800℃）, had more positive onsets, half-wave potentials, and higher catalytic activities for the ORR, which proceeds via a direct four-electron reaction pathway in alkaline media, similar to commercial Pt/C catalysts. Furthermore, HDPC-X also showed enhanced durability and better tolerance to methanol crossover and CO poisoning effects in comparison to commercial Pt/C, making them promising alternatives for state-of-the-art ORR electrocatalysts for electrochemical energy conversion. The method used here provides valuable guidelines for the design of high-performance ORR electrocatalysts from natural sources at the industrial scale.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China （Grant Nos. 21273227 and 21403258） and the Strategic Priority Research Program of the Chinese Academy of Science （Grant Nos XDB 17020400）.
文摘Hydroformylation has been widely used in industry to manufacture high value-added aldehydes and alcohols, and is considered as the largest homogenously catalyzed process in industry. However, this process often suffers from complicated operation and the difficulty in catalyst recycling. It is highly desirable to develop a heterogeneous catalyst that enables the catalyst recovery without sacrificing the activity and selectivity. There are two strategies to afford such a catalyst for the hydrofromylation： immobilized catalysts on solid support and porous organic ligand （POL）-supported catalysts. In the latter, high concentration of phosphine ligands in the catalyst framework is favorable for the high dispersion of rhodium species and the formation of Rh-P multiple bonds, which endow the catalysts with high activity and stability respectively. Besides, the high linear regioselectivity could be achieved through the copolymerization of vinyl functionalized bidentate ligand （vinyl biphephos） and monodentate ligand （3vPPh3） into the catalyst framework. The newly-emerging POL-supported catalysts have great perspectives in the industrial hydroformylation.
