Study of nickel nanoparticles supported on activated carbon prepared by aqueous hydrazine reduction

Nickel nanoparticles were obtained by the reduction in hydrazine aqueous media of nickel acetate as a precursor supported on activated carbon of high surface area. Classical catalysts using nickel acetate or nitrate were prepared for comparison. The catalysts were characterized by N(2) physisorption, H(2)-TPR, H(2)-adsorption, TPD, TEM, and XRD, and tested in the gas phase hydrogenation of benzene. Hydrazine catalysts were found much more active in benzene hydrogenation than corresponding classically prepared catalysts. Remarkably, their reactivity is comparable (turn-over frequency of 0.2001-0.2539 s(-1) at 393 K) to that of Pt classical catalysts supported on activated carbon in the same conditions. Evidence is given for the existence of the hydrogen spillover effect in benzene hydrogenation, not reported before in the literature. As a result of the hydrogen spillover effect, catalysts performances can be explained by a combination of surface metal atom reactivity, metal-support interaction strength, and specific surface area extent. Maximum effect is observed with hydrazine preparation method, for 1% Ni content and nickel acetate as a precursor. Unexpectedly, it was also found that hydrazine preparation increases the specific area of the catalysts.     

Silica supported nanopalladium prepared by hydrazine reduction

Palladium catalysts (1–10 wt.% Pd) supported on silica were prepared by hydrazine reduction of palladium chloride at room temperature. They were characterized by XRD, TEM, EDX, H₂-adsorption, and H₂-TPD and tested in the gas phase hydrogenation of benzene in the temperature range 75–250 °C. A conventional catalyst (1 wt.% Pd) obtained by calcination then hydrogen reduction of the same metal precursor was studied for comparison. Metal particles with a size range 6.8–28.4 nm were obtained. Dispersion, hydrogen storage and activity in benzene hydrogenation increased with decreasing particle size. In comparison, the classical catalyst was found much more dispersed (mean particle size of 1.6 nm) and more active (specific rate 1.6–3.7 times higher) than the homolog hydrazine catalyst. However, unexpectedly, turnover frequency (TOF) calculations indicated a greater reactivity of the metal surface atoms for the hydrazine catalyst. It also stored more hydrogen. These contrasting results are discussed in relation with the metal particle morphology.     

Study of support effects on the reduction of Ni2+ ions in aqueous hydrazine

We have studied the effect of silica of quartz-type on the reducibility of nickel acetate in aqueous hydrazine (80 degrees C, pH = 10-12) and metal particle formation. The obtained materials were characterized by X-ray diffraction, transmission electron microscopy, and thermodesorption experiments. With nickel acetate alone, the reduction was partial (45%) and a metal film at the liquid-gas interface or a powdered metal precipitate with an average particle size of 120 nm was obtained. In the presence of silica as the surfactant, the reduction of nickel acetate was total and the nickel phase deposited as a film on the support with an average particle size of 25 nm. Supported nickel acetate was also totally reduced. Crystallites of a mean particle size of about 3 nm were obtained. Decreasing the nickel content or increasing the hydrazine/nickel ratio decreased the metal particle size. Whiskers were formed for low nickel loadings. Hydrogen thermal treatment of the reduced phase showed that the organic acetate fragment, belonging to the precursor salt, still remained strongly attached to the nickel phase. The amount of the retained organic matrix depended on the metal particle size. Surface defects are suggested as active sites, which enhanced nickel ion reduction in the presence of silica as the surfactant or support. Metal-support interactions and the nucleation/ growth rate were the main factors determining the size and morphology of the supported metal particles formed. The organic matrix covered the reduced nickel phase.     

PET/SiO2 nanocomposites prepared by cryomilling

The mixed powders of poly(ethylene terephthalate) (PET) and SiO₂ has been subjected to cryomilling. The evolution of microstructure with time was characterized using scanning electron microscope, transmission electron microscope, field emission scanning electron microscope, and laser diffraction particle size analyzer. It was shown that, upon cryomilling for 10 h, SiO₂ nano particles were well deconglomerated into single particles (～30 nm) that get homogeneously dispersed in PET matrix. The resulted PET/SiO₂ primary particles were flake‐shaped with a size of 400 nm. These primary composite particles agglomerated to form secondary composite particles with an average size about 7.6 μm. A three‐stage model was purposed for the formation mechanism of the nanocomposite structures induced by cryomilling. Our evidences suggest that cryomilling is a capable and promising technique for the production of polymer/inorganic nanocomposites. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1161–1167, 2006     

Surface properties of Ni-Pt/SiO2 catalysts for N2O decomposition and reduction by H2

The surface properties of bimetallic Ni-Pt/SiO2 catalysts with variable Ni/Ni + Pt atomic ratio (0.75, 0.50, and 0.25) were studied using N2O decomposition and N2O reduction by hydrogen reactions as probes. Catalysts were prepared by incipient wetness impregnation of the silica support with aqueous solutions of the metal precursors to a total metal loading of 2 wt %. For both model reactions, Pt/SiO2 catalyst was substantially more active than Ni/SiO2 catalyst. Mean particle size by TEM was about the same (in the range 6-8 nm) for all catalysts and truly bimetallic particles (more than 95%) were evidenced by EDS in the Ni-Pt/SiO2 catalysts. CO adsorption on the bimetallic catalysts showed differences in the linear CO absorption band as a function of the Ni/Pt atomic ratio. Bimetallic Ni-Pt/SiO2 catalysts showed, for the N2O decomposition, a catalytic behavior that points out an ensemble-size sensitive behavior for Ni-rich compositions. For the N2O + H2 reaction, the bimetallic catalysts were very active at low temperature. The following activity order at 300 K was observed: Ni75Pt25 > Ni25Pt75 approximately Ni50Pt50 > Pt. TOF values for these catalysts increased 2-5 times compared to the most active reference catalyst (Pt/SiO2). The enhancement of the activity in the Ni75Pt25 bimetallic catalysts is explained in terms of the presence of mixed Ni-Pt ensembles.     

液相还原法制备Cu/Zn/Al/Zr催化剂用于CO2加氢合成甲醇

近年来,由于大气CO2浓度增加引起的温室效应正日益威胁着人类的生存与发展,CO2的捕获与利用是有望解决温室效应和能源危机的有效途径.CO2催化转化为甲醇成为众多研究者关注的焦点,这是因为甲醇不仅是一种重要的基本化工原料,也是一种洁净的绿色燃料和能源载体.Cu基催化剂广泛应用于CO2加氢合成甲醇反应,并表现出良好的催化性能.通常,金属催化剂的制备是采用H2对金属氧化物进行还原.然而,传统的气相还原过程伴随着强烈的热效应,且需要在高温(473-573 K)下进行,会引起表面铜颗粒长大并加速其聚集烧结,使得活性组分利用率下降.近年来,以NaBH4为还原剂的液相还原法逐渐受到人们的重视,该方法操作简单、快捷且条件可控,反应在低温下进行,放出的热量可在液相环境中迅速得到转移,大大抑制了铜颗粒的聚集.因此,液相还原法可制备出高铜分散度、高活性的催化剂.焙烧温度对铜基催化剂结构和催化性能的影响已得到广泛探究,但这仅限于含二价铜物种催化剂,焙烧温度对含多种铜价态催化剂的影响未见报道.由于液相还原法制备的催化剂含有还原态的铜物种(Cu0和Cu+),它们比Cu2+具有更强的流动性,因此在后续的焙烧过程中催化剂更容易发生烧结和聚集.本文采用液相还原法合成了Cu/Zn/Al/Zr催化剂,分别于423,573,723和873 K焙烧后用于CO2加氢合成甲醇反应,考察了焙烧温度对制备的铜基催化剂结构性质和催化性能的影响,并与传统共沉淀法制备的催化剂进行了对比.结果显示,随着焙烧温度升高,铜物种聚集作用增强,金属铜颗粒尺寸增大,873 K时烧结出现显著增强.由于比表面积随焙烧温度升高而减小,高温度焙烧的催化剂具有小的表面碱性位数目.焙烧温度会影响催化剂中铜物种与其它组分的相互作用,进而影响催化剂的还原.随着焙烧温度的升高,催化剂的还原温度逐渐降低,表面Cu+/Cu0的比例先增后减.CO2加氢活性评价显示,液相还原法制备的催化剂具有更高的催化活性,尤其是甲醇选择性;随着焙烧温度升高,催化剂的CO2转化率和甲醇选择性先增后减,CZAZ-573催化剂具有最高活性,且在1000 h长周期活性测试中表现稳定.CO2转化率与催化剂暴露金属铜的比表面积密切相关.相比Cu0,产物甲醇更容易在Cu+表面催化生成,催化剂表面的Cu+/Cu0比与甲醇选择性的变化规律一致.通过调控焙烧温度可得到高Cu比表面积以及高Cu+/Cu0比的催化剂,有利于CO2加氢生成甲醇.     

Reactivity of RuO species in RuO2/CeO2 catalysts prepared by a wet reduction method

The paper deals with the reactivity of RuO₂/CeO₂ prepared by a wet reduction method: ruthenium was supported on Ce(OH)₃, which was precipitated by alkali-hydrolysis of Ce(NO₃)₃, under a reduction condition with formaldehyde at pH 11 and transformed into RuO₂/CeO₂ catalysts by calcination in air at 773 K. The catalysts were investigated with an ESR technique and were tested for oxidation of propylene. They had no ESR signals by themselves at room temperature, but gave two sets of anisotropic signals upon contact with propylene. These signals were derived from the reaction products between RuO and propylene. The intensities of the signals were kept unchanged at room temperature for more than 1 h in the absence of excess propylene. The signals decayed in the presence of excess propylene and the upfield signal decayed more rapidly. A prior heating of the catalyst in air at 473 K or above caused the increase in the intensity of the upfield signal. The time course of the signal changes discriminated between ethylene and olefins with allylic hydrogen toward RuO species.     

由亲水和疏水硅胶制备的Co/Ru/SiO2催化剂的表征及催化性能研究

以亲水硅胶Degussa A300和疏水硅胶Degussa R106作为催化剂载体,采用等体积浸渍法制备了一系列钴基催化剂。利用MS、XRD、BET、FT-IR、TPR等手段考察了载体热稳定性,催化剂表面物相结构和还原性能等物化性能。结果表明,载体表面有机基团对催化剂中Co3O4尺寸大小有影响,有机基团对载体表面羟基的取代使得金属钴与载体的作用力减弱,有利于金属团聚为较大的颗粒。费-托反应结果表明,亲水硅胶性制得的催化剂通过后处理引入甲基后,造成催化剂活性下降,C18+的选择性下降,但使烃分布集中在C5～C18,这是由于表面甲基的空间位阻作用不利于反应中的吸附过程和链增长过程。由疏水载体制备的催化剂虽然钴颗粒较大,但是由于催化剂制备过程中部分有机基团的烧结,对催化剂活性产生了较大的负面影响,使催化活性降低,重质烃选择性明显降低。     

Surface oxidation states in Si/SiO2 nanostructures prepared from Si/SiO2 mixtures

Silica nanospheres have been produced by a novel technique where surface Si oxidation states can be adjusted using the ratio of metalloid ions/metalloid atoms in the starting mixture. When the proportions of Si4+/Si0 are equal in the synthesis, the resulting solid is considerably more reactive than Cab-O-Sil toward the phenol hydroxylation reaction and the surface shows an average Si oxidation state of +3. On the other hand, those silica nanospheres, produced from a mixture of Si4+/Si0 = 0.25, showed a lower reactivity comparable to that of Cab-O-Sil which XPS demonstrates has a surprisingly low average Si oxidation state close to +1. We speculate that the silicon surface oxidation state and the number of surface silanol groups play important roles in determining the activity of the solid toward the phenol hydroxylation reaction. In expanding our earlier report4 on the copper-silica system, we establish that the surface chemistry of the silica nanospheres is apparently different from that of fumed, amorphous silica. These results suggest that we are developing a technique that can be generalized to create supported, mixed metal oxides having tunable average surface oxidation states.     

醇预处理载体制备的 Ir-Re/SiO2催化剂上甘油氢解反应

甘油是生物柴油的副产物,将其转化为高附加值的化学品,能提高生物柴油产业的经济性.1,3-丙二醇是聚酯和聚氨酯的单体,也用于合成医药和用作有机合成中间体,甘油直接催化氢解反应制1,3-丙二醇极具发展潜力.另外,甘油是生物质转化的重要平台分子之一,与目标产物的分子结构相比较,生物质平台分子通常含有过多的含氧基团,尤其是多余的羟基,通过甘油氢解反应研究多羟基的选择性活化和脱除,可以加深对生物质脱氧规律的认识.因此,研究甘油氢解反应制1,3-丙二醇催化剂和工艺,不仅具有潜在的应用前景,而且具有重要理论价值.然而,目前的甘油氢解催化剂性能还不够高,我们希望通过一些表面改性的方法处理载体硅胶,从而改变金属前驱体与载体表面的作用.因此,本文使用 C1–C4的正构醇处理硅胶载体,其负载的 Ir-Re催化剂上甘油氢解反应转化率从42.7%提高到59.5%,仲羟基脱除收率从21.6%提高到28.3%.研究发现,当处理载体所用正构醇的碳数从1增加到3时,对应催化剂上甘油转化率逐渐增加至最高;但当使用更正丁醇时,对应催化剂上甘油转化率下降.为了探究催化剂活性改变的原因,我们首先采用红外光谱(FT-IR)和氮气物理吸附确定烷氧基基团嫁接到硅胶载体上.程序升温还原结果发现,预处理载体相应的催化剂开始还原温度降低,表明在这些催化剂上形成了颗粒尺寸较小的Ir粒子. X-射线衍射分析发现,在新鲜的和使用后的催化剂上均未检测出Re物种的衍射峰,说明Re高度分散于催化剂表面.吸附吡啶的FT-IR结果表明,未处理和丙醇预处理硅胶负载的催化剂上均没有强酸位,它们的B/L酸比值相近,约为3.3.催化剂的吸附COFT-IR结果表明, CO线性吸附于Ir/SiO2催化剂上的主要吸收峰位置在2084 cm–1;而Re的加入使得该吸收峰红移,表明Ir和ReOx物种之间存在相互作用.透射电镜(TEM)、H2-程序升温脱附和NH3-程序升温脱附结果发现,醇预处理催化剂上具有更多的Ir-ReOx界面,而界面位点的数量与甘油转化率大小一致,表明Ir-ReOx位点可能就是甘油氢解的活性中心.反应后催化剂的TEM结果表明,醇预处理催化剂上的Ir颗粒要小于未处理催化剂的,其中丙醇预处理硅胶负载的催化剂上Ir粒径最小.这是由于醇处理催化剂上存在很多孤立的Si–OH,它们与金属前驱体相互作用有利于形成较小的金属颗粒.这些孤立的Si-OH则是由于表面烷氧基基团的隔离作用所形成的.当处理载体所用正构醇的碳数从1增加到3时,烷氧基的碳链变长,分隔作用越好,阻止金属前驱体聚集的程度越强,因而Ir物种和Re物种的分散度增加.但是当处理醇的碳数增加到4时,形成的表面烷氧基基团可能阻止了Re物种和Ir物种间相互作用,从而使得Ir和Re物种的分散度均降低,相应催化剂活性随之降低.     

Structure of Pd/SiO2 sol-gel and impregnated catalysts

Palladium catalysts were prepared by sol-gel and impregnation techniques both in acid and basic media. The sol-gel catalysts resulted in larger PdO crystallites than the impregnated catalysts. In both preparation methods, an acid medium promoted the formation of small metal crystallites which provided catalytic activity. A stronger metal-support interaction was found in sol-gel catalysts synthesized from a square planar palladium complex. Deactivation results in phenylacetylene hydrogenation have been attributed to palladium hydrate formation or to deposition of carbonaceous compounds. The preparation mode determined the contribution of each deactivating reaction.     

Ethylene polymerization initiated by SiO2-supported neodymocene catalysts

Some SiO₂-supported neodymocene catalysts were prepared and polymerization of ethylene was conducted with them using alkylaluminiums, methylaluminoxane (MAO), BuLi and Bu MgEt (Bu: butyl, Et: ethyl) as cocatalysts. The lifetime of these catalysts was found to be very long. Catalytic activity as well as molecular weight of the produced polymer are strongly dependent upon kind and amount of cocatalyst used. With increasing polymerization temperature, the activity increases monotonously up to 80°C. The use of BuMgEt and Al(i-C₄H₉)₃ as cocatalyst gives the highest activity and highest molecular weight, respectively.     

The gamma-ray induced chemisorption of oxygen on perovskite type catalysts: Determination by reduction with hydrazine sulphate/hydroxylamine hydrochloride

Chemisorbed oxygen can be determined quantitatively by the measurement of gaseous N₂/N₂O liberated by treatment with hydrazine sulphate/hydroxylamine hydrochloride. The amount of chemisorbed oxygen depends on the degree of dispersion during irradiation and also the -dose. The chemisorption is enhanced in the presence of moisture. The partial reduction of the transition metal ion favours the formation of chemisorbed oxygen.     

Exafs and electron-microscopy studies on V/SiO2 catalysts

Extended x-ray-absorption fine structure and scanning electron microscopy have been applied to the structure of the vanadium oxide layers on impregnated and grafted vanadium aerosils. When aerosil is impregnated with NH₄VO₃ solution, V₂O₅ crystals are formed; when vanadium is grafted by reacting the oxychloride with carrier OH groups, there are no visible crystals. On the other hand, the EXAFS spectra for the grafted specimens show all the oscillations found for crystalline V₂O₅. It is concluded that the vanadium oxide layers in these grafted materials have a long-range order similar to that in V₂O₅ and contain microcrystals having sizes up to 5 nm.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 23, No. 5, pp. 652–655, September–October, 1987.     

基于FeWOx/SiO2载氧体的甲烷化学链部分氧化反应

甲烷具有价格低廉且储量丰富的优点,因此将甲烷转化为合成气(一种H2:CO为2的混合物),从而进一步合成有价值的化学品和液体燃料引起了人们的极大关注.化学链甲烷部分氧化(CLPOM)技术能避免甲烷与空气直接接触而引起爆炸的危险,可以降低后续对合成气与氮气分离操作所带来的费用,因此日益受到关注.CLOPM过程主要分为两步:第一步,CH4被载氧体所携带的氧部分氧化,载氧体被还原;第二步,利用氧化剂(例如空气)将被还原的载氧体再氧化恢复.因此,载氧体在CLOPM过程中起到至关重要的作用.载氧体的选择主要存在两个问题:(1)甲烷被活化所产生含碳产物的能力与晶格氧的给氧能力不匹配所带来的严重碳沉积;(2)金属离子间扩散速率不匹配而造成载氧体在氧化还原过程中结构的不可逆变化.基于上述两个问题,本文设计了FeWOx/SiO2载氧体用于CLPOM.与未改性的WO3/SiO2载氧体相比,甲烷的转化率和合成气的收率都有显著提高.FeWOx/SiO2在900℃、1 atm反应条件下表现出62%的甲烷转化率、93%的CO气相选择性、94%的H2选择性和2.4的H2/CO比值,同时在50个循环中表现出优异的催化活性和稳定性.本工作利用CH4脉冲反应研究了FeWOx/SiO2的甲烷表面反应过程;采用CH4-TPR和H2-TPR相结合探究了甲烷活化速率与晶格氧扩散速率之间的关系;通过XPS和XRD对FeWOx/SiO2在氧化还原过程中的结构稳定性进行了探讨.综合上述实验结果,对FeWOx/SiO2应用于CLPOM的反应机理进行了阐述.H2-TPR结果表明,在FeWOx/SiO2中,相较于Fe2O3/SiO2,Fe-O的活性受到抑制,使其更倾向于与甲烷发生部分氧化反应;相较于WO3/SiO2,W-O的活性得到明显提升,因此更多的晶格氧可以参与到部分氧化反应中来氧化积碳,从而使合成气收率大幅度提升.从CH4-TPR结果可以看出,对于FeWOx/SiO2,CO与H2的生成温度最接近,意味着晶格氧的传输速率较快并且能够与甲烷活化产生含碳中间物种的速率相匹配,将其及时氧化生成CO,避免由于积碳造成的催化剂失活.结合XPS和XRD结果可以得出,在甲烷还原过程中,FeWOx经历一步还原形成Fe-W合金,由于其间存在强相互作用,因而抑制了还原过程中催化剂相分离现象的发生.同时,根据铁钨离子在空气条件下扩散速率的公式计算可以得出,其相近的离子氧化速率也保证了在氧化过程中催化剂结构的稳定性.本工作为进一步构建用于甲烷化学链部分氧化制合成气的复合金属氧化物载氧体提供了研究思路.     

A zirconium modified Co/SiO2 Fischer-Tropsch catalyst prepared by dielectric-barrier discharge plasma

Co/SiO₂ and zirconium promoted Co/Zr/SiO₂ catalysts were prepared using dielectric-barrier discharge (DBD) plasma instead of the conventional thermal calcination method. Fischer-Tropsch Synthesis (FTS) performances of the catalyst were evaluated in a fixed bed reactor. The results indicated that the catalyst treated by DBD plasma shows the higher FTS activity and yield of heavy hydrocarbons as compared with that treated by the conventional thermal calcination method. Increase in CO conversion was unnoticeable on the Co/SiO₂ catalyst, but significant on the Co/Zr/SiO₂ catalyst, both prepared by DBD plasma. On the other hand, heavy hydrocarbon selectivity and chain growth probability (α value) were enhanced on all the catalysts prepared by the DBD plasma. In order to study the effect of the DBD plasma treatment on the FTS performance, the catalysts were characterized by N₂-physisorption, H₂-temperature programed reduction (H₂-TPR), H₂-temperature-programmed desorption (H₂-TPD) and oxygen titration, transmission electron microscope (TEM) and X-ray diffraction (XRD). It was proved that, compared with the traditional calcination method, DBD plasma not only could shorten the precursor decomposition time, but also could achieve better cobalt dispersion, smaller Co₃O₄ cluster size and more uniform cobalt distribution. However, cobalt reducibility was hindered to some extent in the Co/SiO₂ catalyst prepared by DBD plasma, while the zirconium additive prevented significantly the decrease in cobalt reducibility and increased cobalt dispersion as well as the FTS performance.     

Production of hydrogen by oxidative steam reforming of methanol over Cu/SiO2 catalysts

Selective production of hydrogen by oxidative steam reforming of methanol (OSRM) was studied over Cu/SiO₂ catalyst using fixed bed flow reactor. Textural and structural properties of the catalyst were analyzed by various instrumental methods. TPR analysis illustrates that the reduction temperature peak was observed between 510?K and 532?K at various copper loadings and calcination temperatures and the peaks shifted to higher temperature with increasing copper loading and calcination temperature. The XRD and XPS analysis demonstrates that the copper existed in different oxidation states at different conditions: Cu₂O, Cu⁰, CuO and Cu(OH)₂ in uncalcined sample; CuO in calcined sample: Cu₂O and metallic Cu after reduction at 600?K and Cu⁰ and CuO after catalytic test. TEM analysis reveals that at various copper loadings, the copper particle size is in the range between 3.0?nm and 3.8?nm. The Cu particle size after catalytic test increased from 3.6 to 4.8?nm, which is due to the formation of oxides of copper as evidenced from XRD and XPS analysis. The catalytic performance at various Cu loadings shows that with increasing Cu loading from 4.7 to 17.3?wt%, the activity increases and thereafter it decreases. Effect of calcination shows that the sample calcined at 673?K exhibited high activity. The O₂/CH₃OH and H₂O/CH₃OH molar ratios play important role in reaction rate and product distribution. The optimum molar ratios of O₂/CH₃OH and H₂O/CH₃OH are 0.25 and 0.1, respectively. When the reaction temperature varied from 473 to 548?K, the methanol conversion and H₂ production rate are in the range of 21.9–97.5% and 1.2–300.9?mmol?kg^?1?s^?1, respectively. The CO selectivity is negligible at these temperatures. Under the optimum conditions (17.3?wt%, Cu/SiO₂; calcination temperature 673?K; 0.25 O₂/CH₃OH molar ratio, 0.5 H₂O/CH₃OH molar ratio and reaction temperature 548?K), the maximum hydrogen yield obtained was 2.45?mol of hydrogen per mole of methanol. The time on stream stability test showed that the Cu/SiO₂ catalyst is quite stable for 48?h.     

Adsorption property of congo red from aqueous solution by Cu-BTC/SiO 2 composite

The adsorption behavior of congo red from aqueous solution on Cu-BTC/SiO2 was investigated. Cu-BTC/SiO2 with mesoporous structure and large surface area was prepared by loading Cu-BTC into the mesoporous silica using in-situ synthesis method. The X-ray diffraction, scanning electron microscopy, and nitrogen adsorption–desorption analysis were used to characterize the structure and morphology of the prepared materials. The adsorption studies showed that the adsorption isotherm of congo red on Cu-BTC/SiO2 fitted well with Freundlich adsorption model and congo red is easy to be adsorbed by Cu-BTC/SiO2. The thermodynamic study showed that the adsorption behavior of congo red on Cu-BTC/SiO2 is an exothermic process at temperature under investigation.