Conversion of n-Pentanol and n-Butanol over Cu/AC Catalyst

It is already well known that availability of petroleum oil, as a world energy source, is running low. Much work has been done by experts to produce renewable energy, especially using vegetable oil as a raw material. Accordingly, this paper presents preparation and activity test of Cu catalyst using coconut shell activated carbon （AC） as a support, for conversion of n-pentanol and n-butanol to their alkenes as the first step of conversion of ethanol to biogasoline. This conversion is interesting due to any agriculture product containing sugar or starch can be converted to ethanol. Activated carbon was used as a catalyst support because this material is inert; hence, it would not yield unexpected side product, and pollution of environment with the used catalyst can be prevented because the used catalytic metal can easily be recovered. Results of the work showed that coconut shell carbon contained some metals, which disturbed in preparation catalyst by cation exchange process. Washing the carbon with ammonium acetate or HCI solution could reduce the metals content more compared to using water, with optimum concentration for ammonium acetate solution was 1.25 M. Application of Cu/AC in converting n-pentanol and n-butanol, based on qualitative analysis to the products using GLC, GC-MS, and FTIR, when n-pentanol and nitrogen gas were flowed into a reactor filled with Cu/AC catalyst, it could be converted to n-pentene with 200 ℃ as the optimal temperature. While when n-butanol and nitrogen gas were flowed into a reactor filled with more Cu/AC catalyst, the product was supposed to contain its aldehyde and butyl vinyl ether.

Mn-Cu复合催化过硫酸盐降解木质素类污染物的研究

本研究以二氧化锰、硝酸铜和二甲基咪唑为原料,采用共沉淀法制备了MnO_(2)-Cu(mIM)2双金属复合催化剂,利用该催化剂活化过硫酸盐以降解木质素模型物香草酸。采用单因素法及响应面法研究催化剂制备和反应条件对催化剂催化活化效率的影响,进一步探讨了催化剂的催化机理。研究表明,在催化剂用量0.387 g/L、氧化剂初始浓度1.3 mmol/L、pH值为6.1的条件下,可以降解94.23%的香草酸;三维荧光检测表明,该催化剂可以有效催化氧化降解对造纸废水中污染物;电子顺磁共振表征表明,该降解体系中的主要反应活性物质是^(1)O_(2)、·OH和SO_(4)^(-)·,其中非自由基^(1)O_(2)起主要作用。

Preparation, Characterization of CuO/CeO_2 and Cu/CeO_2 Catalysts and Their Applications in Low-Temperature CO Oxidation

CeO2 was synthesized via sol-gel process and used as supporter to prepare CuO/CeO2, Cu/CeO2 catalysts by impregnation method. The catalytic properties and characterization of CeO2, CuO/CeO2 and Cu/CeO2 catalysts were examined by means of a microreactor-GC system, HRTEM, XRD, TPR and XPS techniques. The results show that CuO has not catalytic activity and the activity of CeO2 is quite low for CO oxidation. However, the catalytic activity of CuO/CeO2 and Cu/ CeO2 catalysts increases significantly. Furthermore, the activity of CuO/CeO2 is higher than that of Cu/CeO2 catalysts.

Characterization and performance of Cu/ZnO/Al_2O_3 catalysts prepared via decomposition of M(Cu,Zn)-ammonia complexes under sub-atmospheric pressure for methanol synthesis from H_2 and CO_2

Methanol synthesis from hydrogenation of CO2 is investigated over Cu/ZnO/Al2O3 catalysts prepared by decomposition of M（Cu,Zn）-ammonia complexes （DMAC） at various temperatures.The catalysts were characterized in detail,including X-ray diffraction,N2 adsorption-desorption,N2O chemisorption,temperature-programmed reduction and evolved gas analyses.The influences of DMAC temperature,reaction temperature and specific Cu surface area on catalytic performance are investigated.It is considered that the aurichalcite phase in the precursor plays a key role in improving the physiochemical properties and activities of the final catalysts.The catalyst from rich-aurichalcite precursor exhibits large specific Cu surface area and high space time yield of methanol （212 g/（Lcat·h）;T=513 K,p=3MPa,SV=12000 h-1）.

In_2O_3-modified Cu/SiO_2 as an active and stable catalyst for the hydrogenation of methyl acetate to ethanol

A series of indium oxide‐modified Cu/SiO2catalysts were synthesized and used to produce ethanol via methyl acetate hydrogenation.In‐Cu/SiO2catalyst containing1.0wt%In2O3exhibited the best catalytic activity and stability.The physicochemical properties of the synthesized catalysts were investigated using several characterization methods and the results showed that introducing suitable indium to Cu/SiO2increased the copper dispersion,diminished the copper crystallite size,and enriched the surface Cu+concentration.Furthermore,the Cu/SiO2catalyst gradually deactivated during the stability test,which was mainly attributed to copper sintering and the valence change in surface copper species.In contrast,indium addition can inhibit the thermal transmigration and accumulation of copper nanoparticles to stabilize the catalyst.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.

Selective hydrogenolysis of furfuryl alcohol to 1,5-and 1,2-pentanediol over Cu-LaCoO_3 catalysts with balanced Cu^O-CoO sites

Selective hydrogenolysis of biomass‐derived furfuryl alcohol(FFA)to 1,5‐and 1,2‐pentanediol(PeD)was conducted over Cu‐LaCoO3 catalysts with different Cu loadings;the catalysts were derived from perovskite structures prepared by a one‐step citrate complexing method.The catalytic performances of the Cu‐LaCoO3 catalysts were found to depend on the Cu loading and pretreatment conditions.The catalyst with 10 wt%Cu loading exhibited the best catalytic performance after prereduction in 5%H2‐95%N2,achieving a high FFA conversion of 100%and selectivity of 55.5%for 1,5‐pentanediol(40.3%)and 1,2‐pentanediol(15.2%)at 413 K and 6 MPa H2.This catalyst could be reused four times without a loss of FFA conversion but it resulted in a slight decrease in pentanediol selectivity.Correlation between the structural changes in the catalysts at different states and the simultaneous variation in the catalytic performance revealed that cooperative catalysis between Cu0 and CoO promoted the hydrogenolysis of FFA to PeDs,especially to 1,5‐PeD,while Co0 promoted the hydrogenation of FFA to tetrahydrofurfuryl alcohol(THFA).Therefore,it is suggested that a synergetic effect between balanced Cu0 and CoO sites plays a critical role in achieving a high yield of PeDs with a high 1,5‐/1,2‐pentanediol selectivity ratio during FFA hydrogenolysis.

Cu/AC催化湿式氧化降解苯酚废水性能研究

以前驱体浸渍法制备铜基碳材料(Cu/AC)为催化剂,考察固定床反应器中不同操作条件对催化湿式氧化(CWAO)降解苯酚性能的影响。利用N_(2)-吸附脱附、XRD、XPS、热重技术,对反应前后Cu/AC结构进行表征,探究Cu/AC失活原因。结果表明,Cu/AC催化CWAO反应的最优操作条件为反应温度180℃,反应压力3.0 MPa,液时空速15 mL(g·h),气时空速4.5 L/(g·h),在反应5 h时苯酚、化学需氧量(COD)转化率分别达到97.0%、89.4%。Cu/AC催化剂失活的原因主要为Cu组分流失和表面沉积物的生成。反应过程中,Cu^(+)和Cu^(0)被氧化为更易流失的Cu^(2+),导致Cu组分流失,降低催化活性;此外,部分中间产物沉积在Cu/AC表面,造成催化剂孔道堵塞,暴露的活性位点减少,使得催化活性进一步降低。

Catalytic activity of Cu/ZnO catalysts mediated by MgO promoter in hydrogenation of methyl acetate to ethanol

Hydrogenation of methyl acetate is a key step in ethanol synthesis from dimethyl ether carbonylation and Cu-based catalysts are widely studied.We report here that the hydrogenation activity of Cu/ZnO catalysts can be enhanced by the addition of MgO promoter.The evolution of crystal phases during coprecipitation and the physicochemical properties of calcined and reduced catalysts by X-ray diffraction(XRD),thermogravimetric(TG)-mass spectrometry(MS),Brunauer-Emmett-Teller(BET),transmission electron microscopy(TEM),N_(2)O titration,in situ CO-Fourier transform infrared spectroscopy(FTIR)and H_(2)-temperature programmed reduction(H_(2)-TPR)reveal that the promoter effect likely lies in the presence of Mg^(2+).A proper amount of Mg^(2+)mediates the precipitation process of Cu and Zn,leading to preferable formation of aurichalcite(Cu_(x)Zn_(1-x))5(CO_(3))_(2)(OH)_(6) crystal phase and a small amount of basic carbonates such as hydrozincite Zn_(5)(CO_(3))_(2)(OH)_(6) and malachite Cu_(2) CO_(3)(OH)_(2).The presence of aurichalcite strengthens the interaction between Cu and Zn species,and thus enhances the dispersity of CuO species and helps generation of Cu^(+)species on reduced catalysts.Furthermore,the performance of Cu/ZnO catalysts exhibits an optimal dependence on the Mg loading,i.e.,17.5%.However,too much Mg^(2+)in the precipitation liquid prohibits formation of aurichalcite but enhances formation of basic nitrates,leading to a dramatically reduced hydrogenation activity.These findings may find applications for optimization of other Cu-based catalysts in a wider range of hydrogenation reactions.

Cu single-atom electrocatalyst on nitrogen-containing graphdiyne for CO_(2) electroreduction to CH_(4)

Developing Cu single-atom catalysts(SACs)with well-defined active sites is highly desirable for producing CH4 in the electrochemical CO_(2) reduction reaction and understanding the structure-property relationship.Herein,a new graphdiyne analogue with uniformly distributed N_(2)-bidentate(note that N_(2)-bidentate site=N^N-bidentate site;N_(2)≠dinitrogen gas in this work)sites are synthesized.Due to the strong interaction between Cu and the N_(2)-bidentate site,a Cu SAC with isolated undercoordinated Cu-N_(2) sites(Cu1.0/N_(2)-GDY)is obtained,with the Cu loading of 1.0 wt%.Cu1.0/N_(2)-GDY exhibits the highest Faradaic efficiency(FE)of 80.6% for CH_(4) in electrocatalytic reduction of CO_(2) at-0.96 V vs.RHE,and the partial current density of CH_(4) is 160 mA cm^(-2).The selectivity for CH_(4) is maintained above 70% when the total current density is 100 to 300 mA cm^(-2).More remarkably,the Cu1.0/N_(2)-GDY achieves a mass activity of 53.2 A/mgCu toward CH4 under-1.18 V vs.RHE.In situ electrochemical spectroscopic studies reveal that undercoordinated Cu-N_(2) sites are more favorable in generating key ^(*)COOH and ^(*)CHO intermediate than Cu nanoparticle counterparts.This work provides an effective pathway to produce SACs with undercoordinated Metal-N_(2) sites toward efficient electrocatalysis.

Electronic and geometric structure of the copper-ceria interface on Cu/CeO2 catalysts

The atomic structure of the active sites in Cu/CeO2 catalysts is intimately associated with the copper-ceria interaction. Both the shape of ceria and the loading of copper affect the chemical bonding of copper species on ceria surfaces and the electronic and geometric character of the relevant interfaces. Nanostructured ceria, including particles(polyhedra), rods, and cubes, provides anchoring sites for the copper species. The atomic arrangements and chemical properties of the(111),(110) and(100) facets, preferentially exposed depending on the shape of ceria, govern the copper-ceria interactions and in turn determine their catalytic properties. Also, the metal loading significantly influences the dispersion of copper species on ceria with a specific shape, forming copper layers, clusters, and nanoparticles. Lower copper contents result in copper monolayers and/or bilayers while higher copper loadings lead to multi-layered clusters and faceted particles. The active sites are usually generated via interactions between the copper atoms in the metal species and the oxygen vacancies on ceria, which is closely linked to the number and density of surface oxygen vacancies dominated by the shape of ceria.

Chemical deactivation of Cu-SAPO-18 deNO_x catalyst caused by basic inorganic contaminants in diesel exhaust

Contaminants(K,Na,Ca,and Mg)were introduced into Cu-SAPO-18 via incipient wetness impregnation to investigate their effect on the selective catalytic reduction of NOx with NH3(NH3-SCR)over Cu-SAPO-18.After the introduction of contaminants into Cu-SAPO-18,the quantity of acidic sites and Cu^2+ species in catalyst decreases owing to the replacement of H^+ and Cu^2+ by K^+,Na^+,Ca^2+,and Mg^2+.Furthermore,the loss of isolated Cu^2+ induces the generation of CuO and CuAl2O4-like phases,which causes further loss in the Brunauer-Emmett-Teller surface area of the catalyst.Consequently,the deNOx performance of the contaminated Cu-SAPO-18 catalysts drops.Such decline in NH3-SCR performance becomes more pronounced by increasing the contaminant contents from 0.5 to 1.0 mmol/gcatal.In addition,the deactivation influence of the contaminants on Cu-SAPO-18 is presented in the order of K>Na>Ca>Mg,which is consistent with the order of reduction of acidic sites.To a certain degree,the effect of the acidic sites on the deactivation of Cu-SAPO-18 might be more significant than that of isolated Cu2+ and the catalyst framework.Moreover,kinetic analysis of NH3-SCR was conducted,and the results indicate that there is no influence of contaminants on the NH3-SCR mechanism.

Low-Temperature Denitrification Performance of Cu2O/Activated Carbon Catalysts for Selective Catalytic Reduction of NOx by CO

To improve the denitrification performance of carbon-based materials for sintering flue gas,we prepared a composite catalyst comprising coconut shell activated carbon(AC)modified by thermal oxidation air.The microstructure,the specific surface area,the pore volume,the crystal structure,and functional groups presented in the prepared Cu2O/AC catalysts were thoroughly characterized.By using scanning electron microscopy(SEM),nitrogen adsorption/desorption isotherms,Fourier-transform infrared(FTIR)spectroscopy and X-ray diffractometry(XRD),the effects of Cu2O loading and calcination temperature on Cu2O/AC catalysts were investigated at low temperature(150℃).The research shows that Cu on the Cu2O/AC catalyst is in the form of Cu2O with good crystalline performance and is spherical and uniformly dispersed on the AC surface.The loading of Cu2O increases the active sites and the specific surface area of the reaction gas contact,which is conducive to the rapid progress of the carbon monoxide selective catalytic reduction(CO-SCR)reaction.When the loading of Cu2O was 8%and the calcination temperature was 500℃,the removal rate of NOx facilitated by the Cu2O/AC catalyst reached 97.9%.These findings provide a theoretical basis for understanding the denitrification of sintering flue gas.

Metal-doped(Cu,Zn)Fe2O4 from integral utilization of toxic Zn-containing electric arc furnace dust: An environment-friendly heterogeneous Fenton-like catalyst

Pure metal-doped(Cu,Zn)Fe2O4 was synthesized from Zn-containing electric arc furnace dust(EAFD)by solid-state reaction using copper salt as additive.The effects of pretreated EAFD-to-Cu2(OH)2CO3·6H2O mass ratio,calcination time,and calcination temperature on the structure and catalytic ability were systematically studied.Under the optimum conditions,the decolorization efficiency and total organic carbon(TOC)removal efficiency of the as-prepared ferrite for treating a Rhodamine B solution were approximately 90.0%and 45.0%,respectively,and the decolorization efficiency remained 83.0%after five recycles,suggesting that the as-prepared(Cu,Zn)Fe2O4 was an efficient heterogeneous Fenton-like catalyst with high stability.The high catalytic activity mainly depended on the synergistic effect of iron and copper ions occupying octahedral positions.More importantly,the toxicity characteristic leaching procedure(TCLP)analysis illustrated that the toxic Zncontaining EAFD was transformed into harmless(Cu,Zn)Fe2O4 and that the concentrations of toxic ions in the degraded solution were all lower than the national emission standard(GB/31574-2015),further confirming that the as obtained sample is an environment-friendly heterogeneous Fenton-like catalyst.

High Activity and Selectivity of Cu/SiO_2 Catalyst for the Direct Synthesis of Indole

Copper supported over silica exhibited very high activity and selectivity for the direct synthesis of indole at atmospheric pressure. Under the reaction temperature of 325C,the yield of indole could obtain 88%.

Effects of ZrO_2 Content on Structure and Performance of Cu/CeO_2-ZrO_2 Catalysts for Water-Gas Shift Reaction

Cu/CeO2-ZrO2 catalysts for water-gas shift （WGS） reaction were prepared with co-precipitation method, and the influence of ZrO2 content on the catalytic structure and properties was investigated by the techniques of N2 physical adsorption analysis, XRD and H2-TPR. The results indicate that the BET surface areas of the catalysts are increased in varying degrees due to the presence of ZrO2. With increasing ZrO2 content, the pore size distribution is centered on 1.9 nm. ZrO2 can efficiently restrain the growth of Cu crystal particles. The appropriate amount of ZrO2 in the Cu/CeO2 catalysts can help the catalyst keep better copper dispersion in the WGS reaction, which can lead to both higher catalytic activity and better thermal stability. When ZrO2 content is 10% （atom fraction）, Cu/CeO2-Zr02 catalyst reaches a CO conversion rate of 73.7% at the reaction temperature of 200℃.

Revealing the Promoting Eff ect of CeO_(2)on the Cu/ZnO Catalyst for Methanol Steam Reforming

Cu-based catalysts have been extensively used in methanol steam reforming(MSR)reactions because of their low cost and high effi ciency.ZnO is often used in commercial Cu-based catalysts as both a structural and an electronic promoter to stabilize metal Cu nanoparticles and modify metal–support interfaces.Still,the further addition of chemical promoters is essential to further enhance the MSR reaction performance of the Cu/ZnO catalyst.In this work,CeO_(2)-doped Cu/ZnO catalysts were prepared using the coprecipitation method,and the eff ects of CeO_(2)on Cu-based catalysts were systematically investigated.Doping with appropriate CeO_(2)amounts could stabilize small Cu nanoparticles through a strong interaction between CeO_(2)and Cu,leading to the formation of more Cu+–ZnO x interfacial sites.However,higher CeO_(2)contents resulted in the formation of larger Cu nanoparticles and an excess of Cu+–CeO x interfacial sites.Consequently,the Cu/5CeO_(2)/ZnO catalyst with maximal Cu–ZnO interfaces exhibited the highest H 2 production rate of 94.6 mmolH2/(gcat·h),which was 1.5 and 10.2 times higher than those of Cu/ZnO and Cu/CeO_(2),respectively.

Preparation and characterization of ultrafine Fe-Cu-based catalysts for CO hydrogenation

The ultrafine particles of a new style Fe-Cu-based catalysts for CO hydrogenation were prepared by impregnating the organic sol of Fe（OH）3 and Cu（OH）2 onto the activated Al2O3, in which the organic sol of Fe（OH）3 and Cu（OH）2 were prepared in the microemulsion of dodecylbenzenesulfonic acid sodium（S）/n-butanol（A）/toluene（O）/water with V（A）/V（O） = 0.25 and W（A）/W（S） = 1.50. This catalyst was characterized by particle size analysis, XRD and TG. The results of particle size analysis showed that Fe（OH）3 particles with a mean size of 17.1 nm and Cu（OH）2 particles with an average size of 6.65 um were obtained. TG analysis and XRD patterns suggested that 673 K is the optimal calcination temperature. CO hydrogenation produced C＋OH with a high selectivity above 58 wt% by using the ultrafine particles as catalyst, and the total alcohol yield of 0.250 g·ml^-1 ·h^-1 was obtained when the contents of Al2O3 and K were 88.61 wt% and 1.60 wt%, respectively.

Cu-Fe Catalysts Modified by Rare Earths for Preparation of High Alcohols from Fatty Acid Esters Reduction

In order to increase activity of Cu Fe catalyst and use the mixture of nitrogen and hydrogen directly for preparation of high alcohols by reducing fatty acid esters, rare earths were used to modify the catalyst. Experiments show that yield of high alcohols increases by 3% as 1% Sm 2O 3 is added to the catalyst when the reduction is carried out under pure hydrogen. The yield greatly decreases when the reduction is carried out under the mixture of hydrogen and nitrogen. Catalysts activities modified by Y and Nd can be evidently improved and even enhanced. The yields increase by 33% and 29% when 1% Y 2O 3 and 1% Nd 2O 3 are added to the catalyst, respectively.

Facile One-step Synthesis of Cu2O@Cu Nano-sheet Composites as Reduced Catalyst

Cu2O@Cu nanocomposite was prepared by a simple high temperature calcination reaction in N2 atmosphere.The as-prepared samples were characterized by XRD,SEM and TEM,which indicated that the product formed by nano-sheets stacking had a high specific surface area.The as-synthesized material shows efficient catalytic activity for the reduction of organic compound in aqueous medium,in which 4-nitrophenol can be reduced to p-aminophenol and Congo red can be degraded to colorless solution.

Some insight on the structure/activity relationship of metal nanoparticles in Cu/SiO2 catalysts

The activity of two Cu/SiO2 catalysts prepared by the chemisorption hydrolysis technique has been tested in the hydrogenation reaction of 3-methyl-cyclohexanone. Both catalysts were found to be very active at 60 ℃ and 1 atm of H2. Characterization of the materials by FT-IR of adsorbed CO and TEM put in light the presence of well formed Cu cristallites. By assuming a cuboctahedral model we could show that the hydrogenation activity is linked to high coordination sites on the metal particle. A comparison is also reported with a sample prepared by ammonia evaporation that was found to be inactive in the hydrogenation reaction under the same experimental conditions.