Herein,three supported catalysts,CuO/Al_(2)O_(3),CeO_(2)/Al_(2)O_(3),and CuO-CeO_(2)/Al_(2)O_(3),were synthesized by the convenient impregnation method to reveal the effect of CeO_(2)addition on catalytic performance ...Herein,three supported catalysts,CuO/Al_(2)O_(3),CeO_(2)/Al_(2)O_(3),and CuO-CeO_(2)/Al_(2)O_(3),were synthesized by the convenient impregnation method to reveal the effect of CeO_(2)addition on catalytic performance and reaction mechanism for toluene oxidation.Compared with CuO/Al_(2)O_(3),the T_(50)and T_(90)(the temperatures at 50%and 90%toluene conversion,respectively)of CuO-CeO_(2)/Al_(2)O_(3)were reduced by 33 and 39°C,respectively.N_(2)adsorptiondesorption experiment,XRD,SEM,EDS mapping,Raman,EPR,H_(2)-TPR,O_(2)-TPD,XPS,NH_(3)-TPD,Toluene-TPD,and in-situ DRIFTS were conducted to characterize these catalysts.The excellent catalytic performance of CuO-CeO_(2)/Al_(2)O_(3)could be attributed to its strong coppercerium interaction and high oxygen vacancies concentration.Moreover,in-situ DRIFTS proved that CuO-CeO_(2)/Al_(2)O_(3)promoted the conversion of toluene to benzoate and accelerated the deep degradation path of toluene.This work provided valuable insights into the development of efficient and economical catalysts for volatile organic compounds.展开更多
Catalytic ozonation is an effective wastewater purification process.However,the low ozone mass transfer in packed bubble columns leads to low ozone utilization efficiency(OUE),poor organic degradation performance,and ...Catalytic ozonation is an effective wastewater purification process.However,the low ozone mass transfer in packed bubble columns leads to low ozone utilization efficiency(OUE),poor organic degradation performance,and high energy consumption.Therefore,there is an urgent need to develop efficient supported catalysts that can enhancemass transfer and performance.However,the reaction mechanism of the support on ozone mass transfer remains unclear,which hinders the development of catalytic ozonation applications.In this study,lava rocks(LR)-supported catalysts,specifically CuMn_(2)O_(4)@LR and MnO_(2)–Co_(3)O_(4)@LR,were proposed for catalytic ozonation of IBP degradation due to their superior catalytic activity,stability,and high OUE.Addition of CuMn_(2)O_(4)@LR or MnO_(2)–Co_(3)O_(4)@LR increased IBP removal efficiency from 85%to 91%or 88%,and reduced energy consumption from 2.86 to 2.14 kWh/m^(3)or 2.60 kWh/m^(3),respectively.This improvement was attributed to LRsupported catalysts enhancing mass transfer and promoting O3 decomposition to generate•OH and•O_(2)^(−),leading to IBP degradation.Furthermore,this study investigated the effects of ozone dose,supporter sizes,and catalyst components on ozone-liquid mass transfer.The results revealed that the size of the supporter influenced stacked porosity and consequently affected ozone mass transfer.Larger-sized LR(kLa=0.172 min^(−1))exhibited better mass transfer compared to smaller-sized supports.Based on these findings,it was concluded that both CuMn_(2)O_(4)@LR and MnO_(2)–Co_(3)O_(4)@LR are potential catalysts for catalytic ozonation in residual IBP degradation of pharmaceutical wastewater,and LR showed good credibility as a catalyst supporter.Understanding the effects of supporters and active components on ozone mass transfer provides a fundamental principle for designing supported catalysts in catalytic ozonation applications.展开更多
The simultaneous removal of SO_(2),NO_(x)and Hg^(0)from industrial exhaust flue gas has drawn worldwide attention in recent years.A particularly attractive technique is selective catalytic reduction,which effectively ...The simultaneous removal of SO_(2),NO_(x)and Hg^(0)from industrial exhaust flue gas has drawn worldwide attention in recent years.A particularly attractive technique is selective catalytic reduction,which effectively removes SO_(2),NO_(x)and Hg^(0)at low temperatures.This paper first reviews the simultaneous removal of SO_(2),NO_(x)and Hg^(0)by unsupported and supported catalysts.It then describes and compares the research progress of various carriers,eg.,carbon-based materials,metal oxides,silica,molecular sieves,metal-organic frameworks,and pillared interlayered clays,in the simultaneous removal of SO_(2),NO_(x)and Hg^(0).The effects of flue-gas components(such as O_(2),NH3,HCl,H2 O,SO_(2),NO and Hg^(0))on the removal of SO_(2),NOx,and Hg^(0)are discussed comprehensively and systematically.After summarizing the pollutantremoval mechanism,the review discusses future developments in the simultaneous removal of SO_(2),NOx and Hg^(0)by catalysts.展开更多
A simple and general strategy is described for preparing network supported catalyst through a one-pot synthetic procedure using supramolecular gel as template.This procedure directly attaches ligand to support during ...A simple and general strategy is described for preparing network supported catalyst through a one-pot synthetic procedure using supramolecular gel as template.This procedure directly attaches ligand to support during fabricating the support.Using this strategy,supported CuBr/di-（2-picolyl） amine catalyst with U-shaped fibrillar network was prepared and used in atom transfer radical polymerization of methyl methacrylate.XPS and SEM characterization of the catalyst revealed homogeneous distribution of ligand,sufficient reactive sites,adequate mechanical strength and macroporosity.The polymerization results demonstrated high activity and reusability of such catalyst.This strategy might be extended to other supported catalysts used in column reactors.展开更多
The supported catalysts for propylene polymerization were prepared by milling Mg (OEt)_2 with EB (ethylbenzoate) and treating with TiCl_4 solution. When TiCl_4/(Mg(OEt)_2/EB) (mol.) ratio was increased, decrease in co...The supported catalysts for propylene polymerization were prepared by milling Mg (OEt)_2 with EB (ethylbenzoate) and treating with TiCl_4 solution. When TiCl_4/(Mg(OEt)_2/EB) (mol.) ratio was increased, decrease in contents of-OEt and Ti of the catalysts was observed, while the content of EB increased. It is proved by analyses of IR, X-ray and XPS that during co-milling Mg(OEt)_2 with EB no reactions have taken place. But after treatment with TiCl_4 solution, Mg(OEt)_2 converts into MgCl_2 and EB coordinates on the resulting MgCl_2 carrier, a surface complex forms.The activity of catalysts,isotacticity and vicosimetric molecular weight of polypropylene increase with the decrease of the content of ethoxyl group. The kinetic curves of propene polymerization obtained with present catalysts system display decay curves. It is found from the triad tacticity calculated from the expanded spectra of methyl carbon region that, ethoxyl group in catalyst has an effect on the configuration of polymer chain.展开更多
Catalyst supports have very important effects on catalyst performance.A novel expanded multilayered vermiculite（EML-VMT） is successfully used as the catalyst support for the acetylene hydrochlorination.By mixing car...Catalyst supports have very important effects on catalyst performance.A novel expanded multilayered vermiculite（EML-VMT） is successfully used as the catalyst support for the acetylene hydrochlorination.By mixing carbon on the surface of EML-VMT[i.e.,EML-VMT-C）,the HgCl2/EML-VMT-C achieved a high acetylene conversion of 97.3%,a vinyl chloride selectivity of 100%and a turn over frequency（TOF） value of 8.83 × 10^-3s^-1 at a temperature of 140 C,an acetylene gas hourly space velocity（GHSV） of 108 h^-1,and a feed volume ratio V（HC1）/V（C2H2） of 1.15.Moreover,the HgCl2/EML-VMT-C shows good stability.The EML-VMT also shows potential in the preparation of other EML-VMT-supported catalysts.展开更多
Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3...Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3)Fe oxide/PANI)with a robust hetero-interface,which significantly improves oxygen evolution activities with an overpotential of 270 mV at 10 mA cm^(-2)and specific activity of 2.08 mA cm_(ECSA)^(-2)at overpotential of 300 mV,3.84-fold that of Ni_(3)Fe oxide.It is revealed that the catalyst–support interaction between Ni_(3)Fe oxide and PANI support enhances the Ni–O covalency via the interfacial Ni–N bond,thus promoting the charge and mass transfer on Ni_(3)Fe oxide.Considering the excellent activity and stability,rechargeable Zn-air batteries with optimum Ni_(3)Fe oxide/PANI are assembled,delivering a low charge voltage of 1.95 V to cycle for 400 h at 10 mA cm^(-2).The regulation of the effect of catalyst–support interaction on catalytic activity provides new possibilities for the future design of highly efficient OER catalysts.展开更多
Carbon-supported mercury catalysts are extensivelyemployed in calcium carbide-based polyvinyl chloride(PVC)industries,but the usage of mercury-based catalysts can pose an environmental threat due to the release of mer...Carbon-supported mercury catalysts are extensivelyemployed in calcium carbide-based polyvinyl chloride(PVC)industries,but the usage of mercury-based catalysts can pose an environmental threat due to the release of mercury into the surrounding area during the operation period.In this study,a highly active and stable mercury-based catalyst was developed,utilizing the nitrogen atom of the support as the anchor site to enhance the interaction between active sites(HgCl_(2))and the carbon support(N-AC).Thermal loss rate testing and thermogravimetric analysis results demonstrate that,compared to commercial activated carbon,N-doped carbon can effectively increase the heat stability of HgCl_(2).The obtained mercury-based catalysts(HgCl_(2)/N-AC)exhibit significant catalytic performance,achieving 2.5 times the C2H2 conversion of conventional HgCl_(2)/AC catalysts.Experimental analysis combined with theoretical calculations reveals that,contrary to the Eley-Rideal(ER)mechanism of HgCl_(2)/AC,the HgCl_(2)/N-AC catalyst follows the Langmuir-Hinshelwood(LH)adsorption mechanism.The nitrogen sites and HgCl_(2) on the catalyst enhance the adsorption capabilities of the HCl and C2H2,thereby improving the catalytic performance.Based on the modification of the active center by these solid ligands,the loading amount of HgCl_(2) on the catalyst can be further reduced from the current 6.5%to 3%.Considering the absence of successful industrial applications for mercury-free catalysts,and based on the current annual consumption of commercial mercury chloride catalysts in the PVC industry,the widespread adoption of this technology could annually reduce the usage of chlorine mercury by 500 tons,making a notable contribution to mercury compliance,reduction,and emissions control in China.It also serves as a bridge between mercury-free and low-mercury catalysts.Moreover,this solid ligand technology can assist in the application research of mercury-free catalysts.展开更多
Volatile organic compounds(VOCs)exhausted from industrial processes are the major atmospheric pollutants,which could destroy the ecological environment and make hazards to human health seriously.Catalytic oxidation is...Volatile organic compounds(VOCs)exhausted from industrial processes are the major atmospheric pollutants,which could destroy the ecological environment and make hazards to human health seriously.Catalytic oxidation is regarded as the most competitive strategy for the efficient elimination of low-concentration VOCs.Supported noble metal catalysts are preferred catalysts due to their excellent low-temperature catalytic activity.To further lower the cost of catalysts,single atom catalysts(SAC)have been fabricated and extensively studied for application in VOCs oxidation due to their 100%atom-utilization efficiency and unique catalytic performance.In this review,we comprehensively summarize the recent advances in supported noble metal(e.g.,Pt,Pd,Au,and Ag)catalysts and SAC for VOCs oxidation since 2015.Firstly,this paper focuses on some important influencing factors that affect the activity of supported noble metal catalysts,including particle size,valence state and dispersion of noble metals,properties of the support,metal oxide/ion modification,preparation method,and pretreatment conditions of catalysts.Secondly,we briefly summarize the catalytic performance of SAC for typical VOCs.Finally,we conclude the key influencing factors and provide the prospects and challenges of VOCs oxidation.展开更多
Enhancing the stability of supported noble metal catalysts emerges is a major challenge in both science and industry.Herein,a heterogeneous Pd catalyst(Pd/NCF)was prepared by supporting Pd ultrafine metal nanoparticle...Enhancing the stability of supported noble metal catalysts emerges is a major challenge in both science and industry.Herein,a heterogeneous Pd catalyst(Pd/NCF)was prepared by supporting Pd ultrafine metal nanoparticles(NPs)on nitrogen-doped carbon;synthesized by using F127 as a stabilizer,as well as chitosan as a carbon and nitrogen source.The Pd/NCF catalyst was efficient and recyclable for oxidative carbonylation of phenol to diphenyl carbonate,exhibiting higher stability than Pd/NC prepared without F127 addition.The hydrogen bond between chitosan(CTS)and F127 was enhanced by F127,which anchored the N in the free amino group,increasing the N content of the carbon material and ensuring that the support could provide sufficient N sites for the deposition of Pd NPs.This process helped to improve metal dispersion.The increased metal-support interaction,which limits the leaching and coarsening of Pd NPs,improves the stability of the Pd/NCF catalyst.Furthermore,density functional theory calculations indicated that pyridine N stabilized the Pd^(2+)species,significantly inhibiting the loss of Pd^(2+)in Pd/NCF during the reaction process.This work provides a promising avenue towards enhancing the stability of nitrogen-doped carbon-supported metal catalysts.展开更多
Developing the alternative supported noble metal catalysts with low cost,high catalytic efficiency,and good resistance toward carbon dioxide and water vapor is critically demanded for the oxidative removal of volatile...Developing the alternative supported noble metal catalysts with low cost,high catalytic efficiency,and good resistance toward carbon dioxide and water vapor is critically demanded for the oxidative removal of volatile organic compounds(VOCs).In this work,we prepared the mesoporous chromia-supported bimetallic Co and Ni single-atom(Co_(1)Ni_(1)/meso-Cr_(2)O_(3))and bimetallic Co and Ni nanoparticle(Co_(NP)Ni_(NP)/mesoCr_(2)O_(3))catalysts adopting the one-pot polyvinyl pyrrolidone(PVP)-and polyvinyl alcohol(PVA)-protecting approaches,respectively.The results indicate that the Co_(1)Ni_(1)/meso-Cr_(2)O_(3)catalyst exhibited the best catalytic activity for n-hexane(C_(6)H_(14))combustion(T_(50%)and T_(90%)were 239 and 263℃ at a space velocity of 40,000 mL g^(-1)h^(-1);apparent activation energy and specific reaction rate at 260℃ were 54.7 kJ mol^(-1)and 4.3×10^(-7)mol g^(-1)_(cat)s^(-1),respectively),which was associated with its higher(Cr^(5+)+Cr^(6+))amount,large n-hexane adsorption capacity,and good lattice oxygen mobility that could enhance the deep oxidation of n-hexane,in which Ni_(1) was beneficial for the enhancements in surface lattice oxygen mobility and low-temperature reducibility,while Co_(1) preferred to generate higher contents of the high-valence states of chromium and surface oxygen species as well as adsorption and activation of n-hexane.n-Hexane combustion takes place via the Mars van Krevelen(MvK)mechanism,and its reaction pathways are as follows:n-hexane→olefins or 3-hexyl hydroperoxide→3-hexanone,2-hexanone or 2,5-dimethyltetrahydrofuran→2-methyloxirane or 2-ethyl-oxetane→acrylic acid→CO_x→CO_(2)and H_(2)O.展开更多
The selective hydrogenation of dimethyl toluene-2,4-dicarbamate(TDC)to methyl cyclohexyl-2,4-dicarbamate(also called hydrogenated TDC,HTDC)is an essential process for non-phosgene synthesis of methylcyclohexane-2,4-di...The selective hydrogenation of dimethyl toluene-2,4-dicarbamate(TDC)to methyl cyclohexyl-2,4-dicarbamate(also called hydrogenated TDC,HTDC)is an essential process for non-phosgene synthesis of methylcyclohexane-2,4-diisocyanate.Herein,we prepared a series of supported Rh-based catalysts by the excessive impregnation method and investigated their catalytic performance for the selective hydrogenation of TDC.The emphasis was put on the influence of support properties on the catalytic performance.Among the prepared catalysts,Rh/g-Al_(2)O_(3)performed the best:a HTDC yield of 88.4%was achieved with a 100%conversion of TDC under the conditions of 100℃,3 MPa and 1 h.Furthermore,Rh/γ-Al_(2)O_(3)could be repetitively used for 4 times without a significant loss of its catalytic activity.TEM,XRD,N_(2)adsorption-desorption,H_(2)-TPR,NH_(3)/CO_(2)-TPD,XPS and ICP characterizations were employed to distinguish the properties of the prepared catalysts and the results were correlated with their catalytic performance.It is indicated that the yield of HTDC shows a positive relevance with the percentage of moderate-to-strong acid sites and the content of Rh^(n+)(n≥3)in the catalysts.High values of the percentage and the content can promote a strong interaction between Rh nanoparticles and the supports,facilitating both the transfer of electrons from Rh to the support and the formation of Rh^(n+)species.This is conducive to activating the benzene ring of TDC and thereby improving the yield of HTDC.展开更多
In this study,supported Pd catalysts were prepared and used as heterogeneous catalysts for the activation of peroxymonosulfate(PMS)which successfully degrade bisphenol F(BPF).Among the supported catalysts(i.e.,Pd/SiO_...In this study,supported Pd catalysts were prepared and used as heterogeneous catalysts for the activation of peroxymonosulfate(PMS)which successfully degrade bisphenol F(BPF).Among the supported catalysts(i.e.,Pd/SiO_(2),Pd/CeO_(2),Pd/TiO_(2)and Pd/Al2O3),Pd/TiO_(2)exhibited the highest catalytic activity due to the high isoelectric point and high Pd0 content.Pd/TiO_(2)prepared by the deposition method leads to high Pd dispersion,which are the key factors for efficient BPF degradation.The influencing factors were investigated during the reaction process and two possible degradation pathways were proposed.Density functional theory(DFT)calculations demonstrate that stronger BPF adsorption and BPF degradation with lower reaction barrier occurs on smaller Pd particles.The catalytic activities are strongly dependent on the structural features of the catalysts.Both experiments and theoretical calculations prove that the reaction is actuated by electron transfer rather than radicals.展开更多
Maintaining high metal dispersion of supported metal catalysts to achieve superior reactivity under harsh conditions poses one of the main challenges for their practical applications.Constructing and regulating the st...Maintaining high metal dispersion of supported metal catalysts to achieve superior reactivity under harsh conditions poses one of the main challenges for their practical applications.Constructing and regulating the strong metal-support interactions(SMSI)by diverse methodologies has emerged as one of the promising approaches to fabricating robust supported metal catalysts.In this study,we report an L-ascorbic acid(AA)-inducing strategy to generate SMSI on a titania-supported gold(Au)catalyst after high-temperature treatment in an inert atmosphere(600℃,N_(2)).The AA-induced SMSI can efficiently stabilize Au nanoparticles(NPs)and preserve their catalytic performance.The detailed study reveals that the key to realizing this SMSI is the generation of oxygen vacancies within the TiO_(2) support induced by the adsorbed AA,which drives the formation of the Ti Oxpermeable layer onto the Au NPs.The strategy could be extended to TiO_(2)-supported Au catalysts with different crystal phases and platinum group metals,such as Pt,Pd,and Rh.This work offers a promising novel route to design stable and efficient supported noble metal catalysts by constructing SMSI using simple reducing organic adsorbent.展开更多
A series of Pd catalysts were prepared on different supports（Fe2O3,SiO2,ZnO,MgO,Al2O3,carbon,and Amberlyst-45） and used in the selective hydrogenation of phenol to cyclohexanone in water.The Amberlyst-45 supported P...A series of Pd catalysts were prepared on different supports（Fe2O3,SiO2,ZnO,MgO,Al2O3,carbon,and Amberlyst-45） and used in the selective hydrogenation of phenol to cyclohexanone in water.The Amberlyst-45 supported Pd catalyst（Pd/A-45） was highly active and selective under mild conditions（40-100 ℃,0.2-1 MPa）,giving a selectivity of cyclohexanone higher than 89%even at complete conversion of phenol.Experiments with different Pd loadings（or different particle sizes） confirmed that the formation of cyclohexanone was a structure sensitive reaction,and Pd particles of12-14 nm on Amberlyst-45 gave better selectivity and stability.展开更多
Most of volatile organic compounds （VOCs） are harmful to the atmosphere and human health. Cata‐lytic combustion is an effective way to eliminate VOCs. The key issue is the availability of high per‐formance catalys...Most of volatile organic compounds （VOCs） are harmful to the atmosphere and human health. Cata‐lytic combustion is an effective way to eliminate VOCs. The key issue is the availability of high per‐formance catalysts. Many catalysts including transition metal oxides, mixed metal oxides, and sup‐ported noble metals have been developed. Among these catalysts, the porous ones attract much attention. In this review, we focus on recent advances in the synthesis of ordered mesoporous and macroporous transition metal oxides, perovskites, and supported noble metal catalysts and their catalytic oxidation of VOCs. The porous catalysts outperformed their bulk counterparts. This excel‐lent catalytic performance was due to their high surface areas, high concentration of adsorbed oxy‐gen species, low temperature reducibility, strong interaction between noble metal and support and highly dispersed noble metal nanoparticles and unique porous structures. Catalytic oxidation of carbon monoxide over typical catalysts was also discussed. We made conclusive remarks and pro‐posed future work for the removal of VOCs.展开更多
The reductive transformation of furfural （FAL） into furfuryl alcohol （FOL） is an attractive route for the use of renewable bio‐sources but it suffers from the heavy use of H2. We describe here a highly efficient ...The reductive transformation of furfural （FAL） into furfuryl alcohol （FOL） is an attractive route for the use of renewable bio‐sources but it suffers from the heavy use of H2. We describe here a highly efficient reduction protocol for converting aqueous FAL to FOL. A single phase rutile TiO2 support with a gold catalyst （Au/TiO2‐R） that used CO/H2O as the hydrogen source catalyze this reduction efficiently under mild conditions. By eliminating the consumption of fossil fuel‐derived H2, our pro‐cess has the benefit afforded by using CO as a convenient and cost competitive reducing reagent.展开更多
Nickel and nickel-ceria catalysts supported on high surface area silica, with 6 wt% Ni and 20 wt% CeO2 were prepared by microwave assisted(co) precipitation method. The catalysts were investigated by XRD,TPR and XPS a...Nickel and nickel-ceria catalysts supported on high surface area silica, with 6 wt% Ni and 20 wt% CeO2 were prepared by microwave assisted(co) precipitation method. The catalysts were investigated by XRD,TPR and XPS analyses and they were tested in partial oxidation of methane(CPO). The catalytic reaction was carried out at atmospheric pressure in a temperature range of 400–800℃ with a feed gas mixture containing methane and oxygen in a molecular ratio CH4/O2=2. The Ni catalyst exhibited 60% methane conversion with 60% selectivity to CO already at 500℃. On the contrary, the Ni–Ce catalyst was inert to CPO up to 700℃. Moreover, the former catalyst reproduced its activity at the descending temperatures maintaining a good stability at 600℃, over a reaction time of 80 h, whereas the latter one completely deactivated. Test of CH4 temperature programmed surface reaction(CH4-TPSR) revealed a higher methane activation temperature(> 100℃) for the Ni–Ce catalyst as compared to the Ni one. Noticeable improvement of the ceria containing catalyst occurred when the reaction test started at a temperature higher than the methane decomposition temperature. In this case, the sample achieved the same catalytic behavior of the Ni catalyst. As confirmed by XPS analyses, the distinct electronic state of the supported nickel was responsible for the differences in catalytic behavior.展开更多
An ultrasound-assisted heterogeneous catalytic oxidation process was applied to eliminate sulfur from commercial diesel fuel oil.The studied variables were catalyst concentration,type of catalyst(homogeneous or hetero...An ultrasound-assisted heterogeneous catalytic oxidation process was applied to eliminate sulfur from commercial diesel fuel oil.The studied variables were catalyst concentration,type of catalyst(homogeneous or heterogeneous),oxidizing agent concentration,and the application of ultrasound energy.Supported catalysts were prepared by impregnation of coal fly ash with an iron(Ⅱ)sulfate aqueous solution using ultrasound energy.After drying,the catalyst was calcined at 500℃for 4 h.The oxidizing agent was hydrogen peroxide.Ultrasound energy was applied with a frequency of 47 kHz and an intensity of 147 W.Ethanol was employed for extracting the oxidized compounds from the hydrocarbon mixture.Coal fly ash and ethanol were used with the purpose of applying low-cost raw materials in chemical processes.It was found that under the studied conditions,increasing oxidizing agent concentration and the application of ultrasound energy can enhance the sulfur removal from commercial diesel fuel oil.Catalyst concentration did not play a significant role in the process.Similar results were obtained using homogeneous or heterogeneous catalyst,which is important since the heterogeneous catalyst could be recovered,reactivated,and used in many cycles.展开更多
Polyethylene (PE) grafting 4-vinylpyridine copolymers has been produced as powders of different rushes by theirradiation method. After treatment with methylaluminoxane (MAO), the copolymers were used as supports for C...Polyethylene (PE) grafting 4-vinylpyridine copolymers has been produced as powders of different rushes by theirradiation method. After treatment with methylaluminoxane (MAO), the copolymers were used as supports for Cp_2ZrCl_2catalyst Results of X-ray photoelectron spectroscopy, Fourier transforms infrared spectroscopy, ultraviolet spectroscopy andscanning electron microscope measurements show that the catalytic sites have been linked through MAO on the PE-graft-4-vinylpyridine (PEVP). The percentages of grafting 4-vinylpyridine and supported Cp_2ZrCl_2 depend on the size ofpolyethylene powder. The smaller the polyethylene powder, the more percent of 4-vinylpyridine groups and Cp_2ZrCl_2 existon the polyethylene chains, and the PEVP-supported catalyst has a relatively high activity for ethylene polymerization.展开更多
基金supported by the Science and Technology Program of Guangzhou,China(No.202002020020)the National Natural Science Foundation of China(Nos.51878292 and 42002035).
文摘Herein,three supported catalysts,CuO/Al_(2)O_(3),CeO_(2)/Al_(2)O_(3),and CuO-CeO_(2)/Al_(2)O_(3),were synthesized by the convenient impregnation method to reveal the effect of CeO_(2)addition on catalytic performance and reaction mechanism for toluene oxidation.Compared with CuO/Al_(2)O_(3),the T_(50)and T_(90)(the temperatures at 50%and 90%toluene conversion,respectively)of CuO-CeO_(2)/Al_(2)O_(3)were reduced by 33 and 39°C,respectively.N_(2)adsorptiondesorption experiment,XRD,SEM,EDS mapping,Raman,EPR,H_(2)-TPR,O_(2)-TPD,XPS,NH_(3)-TPD,Toluene-TPD,and in-situ DRIFTS were conducted to characterize these catalysts.The excellent catalytic performance of CuO-CeO_(2)/Al_(2)O_(3)could be attributed to its strong coppercerium interaction and high oxygen vacancies concentration.Moreover,in-situ DRIFTS proved that CuO-CeO_(2)/Al_(2)O_(3)promoted the conversion of toluene to benzoate and accelerated the deep degradation path of toluene.This work provided valuable insights into the development of efficient and economical catalysts for volatile organic compounds.
基金supported by the National Key Research and Development Program of China(No.2021YFE0100800)the National Natural Science Foundation of China(Nos.22076012,52100002,52200035,and 51878047)+4 种基金the Beijing Forestry University Outstanding Young Talent Cultivation Project(No.2019JQ03008)the Yangtze River Joint Research Phase II Program(Nos.2022-LHYJ-02-0510-02,and 2022-LHYJ-02-0502-02-06)the Open Project of State Key Laboratory of Urban Water Resources and Environment(No.HC202328)the Fundamental Research Funds for the Central Universities(No.BLX202153)the China Postdoctoral Science Foundation(No.2021M700448).
文摘Catalytic ozonation is an effective wastewater purification process.However,the low ozone mass transfer in packed bubble columns leads to low ozone utilization efficiency(OUE),poor organic degradation performance,and high energy consumption.Therefore,there is an urgent need to develop efficient supported catalysts that can enhancemass transfer and performance.However,the reaction mechanism of the support on ozone mass transfer remains unclear,which hinders the development of catalytic ozonation applications.In this study,lava rocks(LR)-supported catalysts,specifically CuMn_(2)O_(4)@LR and MnO_(2)–Co_(3)O_(4)@LR,were proposed for catalytic ozonation of IBP degradation due to their superior catalytic activity,stability,and high OUE.Addition of CuMn_(2)O_(4)@LR or MnO_(2)–Co_(3)O_(4)@LR increased IBP removal efficiency from 85%to 91%or 88%,and reduced energy consumption from 2.86 to 2.14 kWh/m^(3)or 2.60 kWh/m^(3),respectively.This improvement was attributed to LRsupported catalysts enhancing mass transfer and promoting O3 decomposition to generate•OH and•O_(2)^(−),leading to IBP degradation.Furthermore,this study investigated the effects of ozone dose,supporter sizes,and catalyst components on ozone-liquid mass transfer.The results revealed that the size of the supporter influenced stacked porosity and consequently affected ozone mass transfer.Larger-sized LR(kLa=0.172 min^(−1))exhibited better mass transfer compared to smaller-sized supports.Based on these findings,it was concluded that both CuMn_(2)O_(4)@LR and MnO_(2)–Co_(3)O_(4)@LR are potential catalysts for catalytic ozonation in residual IBP degradation of pharmaceutical wastewater,and LR showed good credibility as a catalyst supporter.Understanding the effects of supporters and active components on ozone mass transfer provides a fundamental principle for designing supported catalysts in catalytic ozonation applications.
基金supported by the National Natural Science Foundation of China(Nos.52000093,51968034,41807373 and21667015)National Key R&D Program of China(No.2018YFC0213400)+1 种基金China Postdoctoral Science Foundation(Nos.2020T130271,2019M663911XB)Open Fund of National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2019B03)。
文摘The simultaneous removal of SO_(2),NO_(x)and Hg^(0)from industrial exhaust flue gas has drawn worldwide attention in recent years.A particularly attractive technique is selective catalytic reduction,which effectively removes SO_(2),NO_(x)and Hg^(0)at low temperatures.This paper first reviews the simultaneous removal of SO_(2),NO_(x)and Hg^(0)by unsupported and supported catalysts.It then describes and compares the research progress of various carriers,eg.,carbon-based materials,metal oxides,silica,molecular sieves,metal-organic frameworks,and pillared interlayered clays,in the simultaneous removal of SO_(2),NO_(x)and Hg^(0).The effects of flue-gas components(such as O_(2),NH3,HCl,H2 O,SO_(2),NO and Hg^(0))on the removal of SO_(2),NOx,and Hg^(0)are discussed comprehensively and systematically.After summarizing the pollutantremoval mechanism,the review discusses future developments in the simultaneous removal of SO_(2),NOx and Hg^(0)by catalysts.
基金support from the National Natural Science Foundation of China(Nos.20574041 and 20874055)Hi-tech Research and Development Program(863 plan) of China(No.2009AA062903)
文摘A simple and general strategy is described for preparing network supported catalyst through a one-pot synthetic procedure using supramolecular gel as template.This procedure directly attaches ligand to support during fabricating the support.Using this strategy,supported CuBr/di-（2-picolyl） amine catalyst with U-shaped fibrillar network was prepared and used in atom transfer radical polymerization of methyl methacrylate.XPS and SEM characterization of the catalyst revealed homogeneous distribution of ligand,sufficient reactive sites,adequate mechanical strength and macroporosity.The polymerization results demonstrated high activity and reusability of such catalyst.This strategy might be extended to other supported catalysts used in column reactors.
文摘The supported catalysts for propylene polymerization were prepared by milling Mg (OEt)_2 with EB (ethylbenzoate) and treating with TiCl_4 solution. When TiCl_4/(Mg(OEt)_2/EB) (mol.) ratio was increased, decrease in contents of-OEt and Ti of the catalysts was observed, while the content of EB increased. It is proved by analyses of IR, X-ray and XPS that during co-milling Mg(OEt)_2 with EB no reactions have taken place. But after treatment with TiCl_4 solution, Mg(OEt)_2 converts into MgCl_2 and EB coordinates on the resulting MgCl_2 carrier, a surface complex forms.The activity of catalysts,isotacticity and vicosimetric molecular weight of polypropylene increase with the decrease of the content of ethoxyl group. The kinetic curves of propene polymerization obtained with present catalysts system display decay curves. It is found from the triad tacticity calculated from the expanded spectra of methyl carbon region that, ethoxyl group in catalyst has an effect on the configuration of polymer chain.
基金financially supported by National Natural Science Foundation of China(Nos.21163015,21366027)the Doctor Foundation of Bingtuan(No.2014BB004)+2 种基金the National Basic Research Program of China(973Program,No. 2012CB720300)the Program for Changjiang Scholars,Innovative Research Team in University(No.IRT1161)the Program of Science and Technology Innovation Team in Bingtuan(No.2011CC001)
文摘Catalyst supports have very important effects on catalyst performance.A novel expanded multilayered vermiculite（EML-VMT） is successfully used as the catalyst support for the acetylene hydrochlorination.By mixing carbon on the surface of EML-VMT[i.e.,EML-VMT-C）,the HgCl2/EML-VMT-C achieved a high acetylene conversion of 97.3%,a vinyl chloride selectivity of 100%and a turn over frequency（TOF） value of 8.83 × 10^-3s^-1 at a temperature of 140 C,an acetylene gas hourly space velocity（GHSV） of 108 h^-1,and a feed volume ratio V（HC1）/V（C2H2） of 1.15.Moreover,the HgCl2/EML-VMT-C shows good stability.The EML-VMT also shows potential in the preparation of other EML-VMT-supported catalysts.
基金Research Institute for Smart Energy(CDB2)the grant from the Research Institute for Advanced Manufacturing(CD8Z)+4 种基金the grant from the Carbon Neutrality Funding Scheme(WZ2R)at The Hong Kong Polytechnic Universitysupport from the Hong Kong Polytechnic University(CD9B,CDBZ and WZ4Q)the National Natural Science Foundation of China(22205187)Shenzhen Municipal Science and Technology Innovation Commission(JCYJ20230807140402006)Start-up Foundation for Introducing Talent of NUIST and Natural Science Foundation of Jiangsu Province of China(BK20230426).
文摘Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3)Fe oxide/PANI)with a robust hetero-interface,which significantly improves oxygen evolution activities with an overpotential of 270 mV at 10 mA cm^(-2)and specific activity of 2.08 mA cm_(ECSA)^(-2)at overpotential of 300 mV,3.84-fold that of Ni_(3)Fe oxide.It is revealed that the catalyst–support interaction between Ni_(3)Fe oxide and PANI support enhances the Ni–O covalency via the interfacial Ni–N bond,thus promoting the charge and mass transfer on Ni_(3)Fe oxide.Considering the excellent activity and stability,rechargeable Zn-air batteries with optimum Ni_(3)Fe oxide/PANI are assembled,delivering a low charge voltage of 1.95 V to cycle for 400 h at 10 mA cm^(-2).The regulation of the effect of catalyst–support interaction on catalytic activity provides new possibilities for the future design of highly efficient OER catalysts.
基金supported by the National Key Research and Development Program of China(2024YFC3907904).
文摘Carbon-supported mercury catalysts are extensivelyemployed in calcium carbide-based polyvinyl chloride(PVC)industries,but the usage of mercury-based catalysts can pose an environmental threat due to the release of mercury into the surrounding area during the operation period.In this study,a highly active and stable mercury-based catalyst was developed,utilizing the nitrogen atom of the support as the anchor site to enhance the interaction between active sites(HgCl_(2))and the carbon support(N-AC).Thermal loss rate testing and thermogravimetric analysis results demonstrate that,compared to commercial activated carbon,N-doped carbon can effectively increase the heat stability of HgCl_(2).The obtained mercury-based catalysts(HgCl_(2)/N-AC)exhibit significant catalytic performance,achieving 2.5 times the C2H2 conversion of conventional HgCl_(2)/AC catalysts.Experimental analysis combined with theoretical calculations reveals that,contrary to the Eley-Rideal(ER)mechanism of HgCl_(2)/AC,the HgCl_(2)/N-AC catalyst follows the Langmuir-Hinshelwood(LH)adsorption mechanism.The nitrogen sites and HgCl_(2) on the catalyst enhance the adsorption capabilities of the HCl and C2H2,thereby improving the catalytic performance.Based on the modification of the active center by these solid ligands,the loading amount of HgCl_(2) on the catalyst can be further reduced from the current 6.5%to 3%.Considering the absence of successful industrial applications for mercury-free catalysts,and based on the current annual consumption of commercial mercury chloride catalysts in the PVC industry,the widespread adoption of this technology could annually reduce the usage of chlorine mercury by 500 tons,making a notable contribution to mercury compliance,reduction,and emissions control in China.It also serves as a bridge between mercury-free and low-mercury catalysts.Moreover,this solid ligand technology can assist in the application research of mercury-free catalysts.
基金supported by Beijing Natural Science Foundation(No.8244060)China Postdoctoral Science Foundation(No.2023M730143)+3 种基金the National Natural Science Foundation of China(No.22425601)the National Key R&D Program of China(No.2023YFB3810801)Beijing Nova Program(No.20240484659)the R&D Program of Beijing Municipal Education Commission(No.KZ202210005011).
文摘Volatile organic compounds(VOCs)exhausted from industrial processes are the major atmospheric pollutants,which could destroy the ecological environment and make hazards to human health seriously.Catalytic oxidation is regarded as the most competitive strategy for the efficient elimination of low-concentration VOCs.Supported noble metal catalysts are preferred catalysts due to their excellent low-temperature catalytic activity.To further lower the cost of catalysts,single atom catalysts(SAC)have been fabricated and extensively studied for application in VOCs oxidation due to their 100%atom-utilization efficiency and unique catalytic performance.In this review,we comprehensively summarize the recent advances in supported noble metal(e.g.,Pt,Pd,Au,and Ag)catalysts and SAC for VOCs oxidation since 2015.Firstly,this paper focuses on some important influencing factors that affect the activity of supported noble metal catalysts,including particle size,valence state and dispersion of noble metals,properties of the support,metal oxide/ion modification,preparation method,and pretreatment conditions of catalysts.Secondly,we briefly summarize the catalytic performance of SAC for typical VOCs.Finally,we conclude the key influencing factors and provide the prospects and challenges of VOCs oxidation.
基金support by the National Natural Science Foundation of China(U21A20306,U20A20152)Natural Science Foundation of Hebei Province(B2022202077).
文摘Enhancing the stability of supported noble metal catalysts emerges is a major challenge in both science and industry.Herein,a heterogeneous Pd catalyst(Pd/NCF)was prepared by supporting Pd ultrafine metal nanoparticles(NPs)on nitrogen-doped carbon;synthesized by using F127 as a stabilizer,as well as chitosan as a carbon and nitrogen source.The Pd/NCF catalyst was efficient and recyclable for oxidative carbonylation of phenol to diphenyl carbonate,exhibiting higher stability than Pd/NC prepared without F127 addition.The hydrogen bond between chitosan(CTS)and F127 was enhanced by F127,which anchored the N in the free amino group,increasing the N content of the carbon material and ensuring that the support could provide sufficient N sites for the deposition of Pd NPs.This process helped to improve metal dispersion.The increased metal-support interaction,which limits the leaching and coarsening of Pd NPs,improves the stability of the Pd/NCF catalyst.Furthermore,density functional theory calculations indicated that pyridine N stabilized the Pd^(2+)species,significantly inhibiting the loss of Pd^(2+)in Pd/NCF during the reaction process.This work provides a promising avenue towards enhancing the stability of nitrogen-doped carbon-supported metal catalysts.
基金supported by the National Natural Science Committee of China-Liaoning Provincial People's Government Joint Fund(U1908204)National Natural Science Foundation of China(21876006,21976009,and 21961160743)+2 种基金Foundation on the Creative Research Team Construction Promotion Project of Beijing Municipal Institutions(IDHT20190503)Natural Science Foundation of Beijing Municipal Commission of Education(KM201710005004)Development Program for the Youth Outstanding-Notch Talent of Beijing Municipal Commission of Education(CIT&TCD201904019)。
文摘Developing the alternative supported noble metal catalysts with low cost,high catalytic efficiency,and good resistance toward carbon dioxide and water vapor is critically demanded for the oxidative removal of volatile organic compounds(VOCs).In this work,we prepared the mesoporous chromia-supported bimetallic Co and Ni single-atom(Co_(1)Ni_(1)/meso-Cr_(2)O_(3))and bimetallic Co and Ni nanoparticle(Co_(NP)Ni_(NP)/mesoCr_(2)O_(3))catalysts adopting the one-pot polyvinyl pyrrolidone(PVP)-and polyvinyl alcohol(PVA)-protecting approaches,respectively.The results indicate that the Co_(1)Ni_(1)/meso-Cr_(2)O_(3)catalyst exhibited the best catalytic activity for n-hexane(C_(6)H_(14))combustion(T_(50%)and T_(90%)were 239 and 263℃ at a space velocity of 40,000 mL g^(-1)h^(-1);apparent activation energy and specific reaction rate at 260℃ were 54.7 kJ mol^(-1)and 4.3×10^(-7)mol g^(-1)_(cat)s^(-1),respectively),which was associated with its higher(Cr^(5+)+Cr^(6+))amount,large n-hexane adsorption capacity,and good lattice oxygen mobility that could enhance the deep oxidation of n-hexane,in which Ni_(1) was beneficial for the enhancements in surface lattice oxygen mobility and low-temperature reducibility,while Co_(1) preferred to generate higher contents of the high-valence states of chromium and surface oxygen species as well as adsorption and activation of n-hexane.n-Hexane combustion takes place via the Mars van Krevelen(MvK)mechanism,and its reaction pathways are as follows:n-hexane→olefins or 3-hexyl hydroperoxide→3-hexanone,2-hexanone or 2,5-dimethyltetrahydrofuran→2-methyloxirane or 2-ethyl-oxetane→acrylic acid→CO_x→CO_(2)and H_(2)O.
基金financially supported by National Natural Science Foundation of China(U21A20306,21978066)Hebei Province Fig.7.Reaction mechanism of selective hydrogenation of TDC over Rh-based catalysts.Graduate Innovation Funding Project(CXZZBS2023033).
文摘The selective hydrogenation of dimethyl toluene-2,4-dicarbamate(TDC)to methyl cyclohexyl-2,4-dicarbamate(also called hydrogenated TDC,HTDC)is an essential process for non-phosgene synthesis of methylcyclohexane-2,4-diisocyanate.Herein,we prepared a series of supported Rh-based catalysts by the excessive impregnation method and investigated their catalytic performance for the selective hydrogenation of TDC.The emphasis was put on the influence of support properties on the catalytic performance.Among the prepared catalysts,Rh/g-Al_(2)O_(3)performed the best:a HTDC yield of 88.4%was achieved with a 100%conversion of TDC under the conditions of 100℃,3 MPa and 1 h.Furthermore,Rh/γ-Al_(2)O_(3)could be repetitively used for 4 times without a significant loss of its catalytic activity.TEM,XRD,N_(2)adsorption-desorption,H_(2)-TPR,NH_(3)/CO_(2)-TPD,XPS and ICP characterizations were employed to distinguish the properties of the prepared catalysts and the results were correlated with their catalytic performance.It is indicated that the yield of HTDC shows a positive relevance with the percentage of moderate-to-strong acid sites and the content of Rh^(n+)(n≥3)in the catalysts.High values of the percentage and the content can promote a strong interaction between Rh nanoparticles and the supports,facilitating both the transfer of electrons from Rh to the support and the formation of Rh^(n+)species.This is conducive to activating the benzene ring of TDC and thereby improving the yield of HTDC.
基金supported by the National Natural Science Foundation of China(NSFC)(No.21978137).
文摘In this study,supported Pd catalysts were prepared and used as heterogeneous catalysts for the activation of peroxymonosulfate(PMS)which successfully degrade bisphenol F(BPF).Among the supported catalysts(i.e.,Pd/SiO_(2),Pd/CeO_(2),Pd/TiO_(2)and Pd/Al2O3),Pd/TiO_(2)exhibited the highest catalytic activity due to the high isoelectric point and high Pd0 content.Pd/TiO_(2)prepared by the deposition method leads to high Pd dispersion,which are the key factors for efficient BPF degradation.The influencing factors were investigated during the reaction process and two possible degradation pathways were proposed.Density functional theory(DFT)calculations demonstrate that stronger BPF adsorption and BPF degradation with lower reaction barrier occurs on smaller Pd particles.The catalytic activities are strongly dependent on the structural features of the catalysts.Both experiments and theoretical calculations prove that the reaction is actuated by electron transfer rather than radicals.
基金supported by the National Natural Science Foundation of China(NSFC)the Japan Society for the Promotion of Science(JSPS)under the Joint Research Program(Nos.NSFC21961142006 and JPJSJRP20191804)+3 种基金NSFC(Nos.U22A20394 and 22375200)the DICP.CAS-Cardiff Joint Research Units(No.121421ZYLH20230008)the International Partnership Program of Chinese Academy of Sciences(No.028GJHZ2023097GC)the China Postdoctoral Science Foundation(No.2022M723086)。
文摘Maintaining high metal dispersion of supported metal catalysts to achieve superior reactivity under harsh conditions poses one of the main challenges for their practical applications.Constructing and regulating the strong metal-support interactions(SMSI)by diverse methodologies has emerged as one of the promising approaches to fabricating robust supported metal catalysts.In this study,we report an L-ascorbic acid(AA)-inducing strategy to generate SMSI on a titania-supported gold(Au)catalyst after high-temperature treatment in an inert atmosphere(600℃,N_(2)).The AA-induced SMSI can efficiently stabilize Au nanoparticles(NPs)and preserve their catalytic performance.The detailed study reveals that the key to realizing this SMSI is the generation of oxygen vacancies within the TiO_(2) support induced by the adsorbed AA,which drives the formation of the Ti Oxpermeable layer onto the Au NPs.The strategy could be extended to TiO_(2)-supported Au catalysts with different crystal phases and platinum group metals,such as Pt,Pd,and Rh.This work offers a promising novel route to design stable and efficient supported noble metal catalysts by constructing SMSI using simple reducing organic adsorbent.
基金supported by the National Natural Science Foundation of China(21473155,21273198,21073159)the Natural Science Foundation of Zhejiang Province(LZ12B03001)~~
文摘A series of Pd catalysts were prepared on different supports（Fe2O3,SiO2,ZnO,MgO,Al2O3,carbon,and Amberlyst-45） and used in the selective hydrogenation of phenol to cyclohexanone in water.The Amberlyst-45 supported Pd catalyst（Pd/A-45） was highly active and selective under mild conditions（40-100 ℃,0.2-1 MPa）,giving a selectivity of cyclohexanone higher than 89%even at complete conversion of phenol.Experiments with different Pd loadings（or different particle sizes） confirmed that the formation of cyclohexanone was a structure sensitive reaction,and Pd particles of12-14 nm on Amberlyst-45 gave better selectivity and stability.
基金supported by the National High Technology Research and Development Program (863 Program,2015AA034603)the National Natural Science Foundation of China (21377008,201077007,20973017)+1 种基金Foundation on the Creative Research Team Construction Promotion Project of Beijing Municipal InstitutionsScientific Research Base Construction-Science and Technology Creation Platform National Materials Research Base Construction~~
文摘Most of volatile organic compounds （VOCs） are harmful to the atmosphere and human health. Cata‐lytic combustion is an effective way to eliminate VOCs. The key issue is the availability of high per‐formance catalysts. Many catalysts including transition metal oxides, mixed metal oxides, and sup‐ported noble metals have been developed. Among these catalysts, the porous ones attract much attention. In this review, we focus on recent advances in the synthesis of ordered mesoporous and macroporous transition metal oxides, perovskites, and supported noble metal catalysts and their catalytic oxidation of VOCs. The porous catalysts outperformed their bulk counterparts. This excel‐lent catalytic performance was due to their high surface areas, high concentration of adsorbed oxy‐gen species, low temperature reducibility, strong interaction between noble metal and support and highly dispersed noble metal nanoparticles and unique porous structures. Catalytic oxidation of carbon monoxide over typical catalysts was also discussed. We made conclusive remarks and pro‐posed future work for the removal of VOCs.
基金supported by the National Natural Science Foundation of China (21273044, 21473035, 91545108)the Research Fund for the Doctoral Program of Higher Education (2012007000011)+2 种基金SINOPEC (X514005)Science & Technology Commission of Shanghai Municipality (08DZ2270500)the Open Project of State Key Laboratory of Chemical Engineering (SKL-ChE-15C02)~~
文摘The reductive transformation of furfural （FAL） into furfuryl alcohol （FOL） is an attractive route for the use of renewable bio‐sources but it suffers from the heavy use of H2. We describe here a highly efficient reduction protocol for converting aqueous FAL to FOL. A single phase rutile TiO2 support with a gold catalyst （Au/TiO2‐R） that used CO/H2O as the hydrogen source catalyze this reduction efficiently under mild conditions. By eliminating the consumption of fossil fuel‐derived H2, our pro‐cess has the benefit afforded by using CO as a convenient and cost competitive reducing reagent.
基金The Executive Programme for Cooperation between Italy and India (Prot.No.MAE01054762017)。
文摘Nickel and nickel-ceria catalysts supported on high surface area silica, with 6 wt% Ni and 20 wt% CeO2 were prepared by microwave assisted(co) precipitation method. The catalysts were investigated by XRD,TPR and XPS analyses and they were tested in partial oxidation of methane(CPO). The catalytic reaction was carried out at atmospheric pressure in a temperature range of 400–800℃ with a feed gas mixture containing methane and oxygen in a molecular ratio CH4/O2=2. The Ni catalyst exhibited 60% methane conversion with 60% selectivity to CO already at 500℃. On the contrary, the Ni–Ce catalyst was inert to CPO up to 700℃. Moreover, the former catalyst reproduced its activity at the descending temperatures maintaining a good stability at 600℃, over a reaction time of 80 h, whereas the latter one completely deactivated. Test of CH4 temperature programmed surface reaction(CH4-TPSR) revealed a higher methane activation temperature(> 100℃) for the Ni–Ce catalyst as compared to the Ni one. Noticeable improvement of the ceria containing catalyst occurred when the reaction test started at a temperature higher than the methane decomposition temperature. In this case, the sample achieved the same catalytic behavior of the Ni catalyst. As confirmed by XPS analyses, the distinct electronic state of the supported nickel was responsible for the differences in catalytic behavior.
文摘An ultrasound-assisted heterogeneous catalytic oxidation process was applied to eliminate sulfur from commercial diesel fuel oil.The studied variables were catalyst concentration,type of catalyst(homogeneous or heterogeneous),oxidizing agent concentration,and the application of ultrasound energy.Supported catalysts were prepared by impregnation of coal fly ash with an iron(Ⅱ)sulfate aqueous solution using ultrasound energy.After drying,the catalyst was calcined at 500℃for 4 h.The oxidizing agent was hydrogen peroxide.Ultrasound energy was applied with a frequency of 47 kHz and an intensity of 147 W.Ethanol was employed for extracting the oxidized compounds from the hydrocarbon mixture.Coal fly ash and ethanol were used with the purpose of applying low-cost raw materials in chemical processes.It was found that under the studied conditions,increasing oxidizing agent concentration and the application of ultrasound energy can enhance the sulfur removal from commercial diesel fuel oil.Catalyst concentration did not play a significant role in the process.Similar results were obtained using homogeneous or heterogeneous catalyst,which is important since the heterogeneous catalyst could be recovered,reactivated,and used in many cycles.
基金National Natural Science Foundation of China (No. 20272062)
文摘Polyethylene (PE) grafting 4-vinylpyridine copolymers has been produced as powders of different rushes by theirradiation method. After treatment with methylaluminoxane (MAO), the copolymers were used as supports for Cp_2ZrCl_2catalyst Results of X-ray photoelectron spectroscopy, Fourier transforms infrared spectroscopy, ultraviolet spectroscopy andscanning electron microscope measurements show that the catalytic sites have been linked through MAO on the PE-graft-4-vinylpyridine (PEVP). The percentages of grafting 4-vinylpyridine and supported Cp_2ZrCl_2 depend on the size ofpolyethylene powder. The smaller the polyethylene powder, the more percent of 4-vinylpyridine groups and Cp_2ZrCl_2 existon the polyethylene chains, and the PEVP-supported catalyst has a relatively high activity for ethylene polymerization.
