Preparation and characterization of vanadium(IV) oxide supported on SBA-15 and its catalytic performance in benzene hydroxylation to phenol using molecular oxygen

Preparation of dispersed transition metal oxides catalyst with low oxidation state still remains a challenging task in heterogeneous catalysis.In this study,vanadium oxides supported on zeolite SBA-15 have been prepared under hydrothermal condition using V 2 O 5 and oxalic acid as sources of vanadium and reductant,respectively.The structures of samples,especially the oxidation state of vanadium,and the surface distribution of vanadium oxide species,have been thoroughly characterized using various techniques,including N 2-physisorption,X-ray diffraction（XRD）,transmission electron microscopy（TEM）,X-ray photoelectron spectroscopy（XPS）,UV-visible spectra（UV-Vis） and UV-visible-near infrared spectra（UV-Vis-NIR）.It is found that the majority of supported vanadium was in the form of vanadium（IV） oxide species with the low valence of vanadium.By adjusting hydrothermal treatment time,the surface distribution of vanadium（IV） oxide species can be tuned from vanadium（IV） oxide cluster to crystallites.These materials have been tested in the hydroxylation of benzene to phenol in liquid-phase with molecular oxygen in the absence of reductant.The catalyst exhibits high selectivity for phenol（61%） at benzene conversion of 4.6%,which is a relatively good result in comparison with other studies employing molecular oxygen as the oxidant.

Effect of Cu promoter on Ni-based SBA-15 catalysts for partial oxidation of methane to syngas

A series of Ni/SBA-15 catalysts with 5wt% to 15wt% Ni content as well as a series of 12.5%Ni/Cu/SBA-15 catalysts with 1% to 10% copper content were prepared by the impregnation method. The catalytic performance for partial oxidation of methane was investigated in a continuous flow microreactor under atmospheric pressure. The textural and chemical properties of the catalysts were characterized by XRD, TEM, BET and Hz-TPR techniques. The results indicated that the catalysts modified with Cu promoter showed better performance than those without modification. For the 12.5%Ni/2.5%/Cu/SBA-15 catalyst, at 850 ℃ the conversion of CH4 reached 97.9% and the selectivity of CO and H2 reached 98.0% and 96.0%, respectively. In XRD patterns of the Ni/Cu/SBA-15 catalyst with 7.5 to 10% Cu contents there were CuO characteristic peaks beside NiO characteristic peaks. The mesoporous structure of SBA-15 was retained in all of the catalysts. TPR analysis of the catalysts revealed that a strong interaction between Ni, Cu promoter and SBA-15 support may be existed. This interaction enhanced significantly the redox properties of the catalysts resulting in the higher catalytic activity.

Selective oxidation of ethane to aldehydes over SBA-15 supported molybdenum catalyst

SBA-15 supported Mo catalysts （Moy/SBA-15） were prepared by an ultrasonic assisted incipient-wetness impregnation method. The physical and chemical properties of the catalysts were characterized by means of N2-adsorption-desorption, XRD, TEM, UV-Vis, Raman, XANES and H2-TPR. The results showed that a trace amount of MoO3 was produced on high Mo content samples. Tum-over frequency （TOF） and product selectivity are dependent on the molybdenum content. Both Mo0.75/SBA-15 and Mo1.75/SBA-15 catalysts give the higher catalytic activity and the selectivity to the total aldehydes for the selective oxidation of C2H6. At the reaction temperature of 625℃, the maximum yield of aldehydes reached 4.2% over Mo0.75/SBA-15 catalyst. The improvement of the activity and selectivity was related with the state of MoOx species.

Nb-SBA-15的制备及催化氧化脱硫的研究

以纯硅介孔分子筛SBA-15为载体,铌酸为铌源,采用后合成法制备了催化剂Nb-SBA-15,通过X射线衍射(XRD)、BET分析、差热分析对所制样品进行了表征。以异辛烷的二苯并噻吩溶液为模拟汽油,对介孔分子筛催化剂Nb-SBA-15的制备条件以及催化氧化脱硫性能进行了研究。实验结果表明,当铌酸负载量小于30%时,催化剂Nb-SBA-15仍具有规则的二维六方介孔结构。介孔分子筛催化剂Nb-SBA-15具有较高的催化活性和稳定性,在铌酸负载量为15%、催化剂焙烧温度为300℃、反应温度为60℃、反应时间为60 min、氧化剂H_2O_2与硫摩尔比为3、剂(N-甲基吡咯烷酮、NMP)油体积比为1、催化剂用量为5%时,脱硫率可达96.30%。

MgO-SBA-15负载的Pd-Pb催化剂催化甲基丙烯醛氧化酯化生成甲基丙烯酸甲酯的反应（英文）

Novel Mg O–SBA-15 supported catalysts were prepared for oxidative esterification of methacrolein(MAL) with methanol to methyl methacrylate(MMA). The Mg O–SBA-15 supports were synthesized with different magnesia loadings from different magnesium precursors and hydrochloric acid molar concentrations. The Mg O–SBA-15 supports and Pd–Pb/Mg O–SBA-15 catalysts were characterized by several analysis methods. The results revealed that the addition of Mg O improved the ordered structure of SBA-15 supports and provided surface alkalinity of SBA-15 supports. The average size of the Pd3 Pb particles on magnesia-modified Pd–Pb/Mg O–SBA-15 catalysts was smaller than that on the pure silica-based Pd–Pb/SBA-15 catalysts. The experiments on catalyst performance showed that the magnesia-modified Pd–Pb/Mg O–SBA-15 catalysts had higher activity than pure silica-based Pd–Pb/SBA-15 catalysts, showing the strong dependence of catalytic activity on the average size of active particles. The difference of activity between Pd–Pb/SBA-15 catalysts and Pd–Pb/Mg O–SBA-15 catalysts was due to the discrepant structural properties and surface alkalinity provided by Mg O, which led to the different Pd3 Pb particle sizes and then resulted in the different number of active sites. Besides magnesia loadings, other factors, such as hydrochloric acid molar concentration and magnesium precursors, had considerable influences on the catalytic activity.

Catalytic Properties of Various Oxides and Mesoporous Materials Containing Niobium and Sulfate Ions, in the Oxidation Reaction of 1-Octanol

Several types of solid acid catalysts were prepared based on oxides like (ZrO2, TiO2, HfO2, MCM-41 and SBA-15). Each catalyst was subjected separately to two types of impregnations: sulfate ions and niobium. The catalytic activity of these solids was tested in the oxidation reaction of 1-octanol. These catalysts showed acidic and redox characters. MCM-41 and SBA-15 materials showed higher redox catalytic activities through the formation of (octyl octanoate, peroxyacetal and octanal). Our interest was focused on obtaining the ester (octyl octanoate) with high yields.

Solvent-free aerobic oxidation of ethylbenzene over supported Ni catalysts using molecular oxygen at atmospheric pressure

We investigated the aerobic oxidation of ethylbenzene in the absence of solvent or any additive carried out over Ni on different types of supports namely SiO2, hydroxyapatite, SBA-15, and USY Zeolites. The oxidation of ethylbenzene activities was measured in a round bottom flask immersed in oil bath at known reaction temperature. The physicochemical characteristics of the catalysts were examined by BET surface area, XRD, FT-IR and the oxidation activities were correlated with the acidities of the catalysts obtained by TPD of NH3. It was observed that both hydroxyapatite and USY （13% Na2O） supported Ni catalysts displayed higher ethylbenzene conversion and 80% selectivity towards acetophenone.

Oxidation Reactivities of Organic Sulfur Compounds in Fuel Oil Using Immobilized Heteropoly Acid as Catalyst

Heteropoly acid of Keggin structure phosphotungstic（HPW） and phosphomolybdic（HPMo） were chemically anchored to the modified SBA-15 channel. The materials were used as catalyst for oxidative desulfurization of organic sulfur compounds including benzothiophene （BT）, dibenzothiophene （DBT） and 4,6-dimethydibenzothiophene （4,6-DMDBT）. The experimental results show that the catalysts are efficient and reusable, the catalytic activity is hardly reduced even in the 5th cycle of use.

Interfacial oxidized Pd species dominate catalytic hydrogenation of polar unsaturated bonds

The determination of catalytically active sites is crucial for the design of efficient and stable catalysts toward desired reactions.However,the complexity of supported noble metal catalysts has led to controversy over the locations of catalytically active sites(e.g.,metal,support,and metal/support interface).Here we develop a structurally controllable catalyst system(Pd/SBA-15)to reveal the catalytic active sites for the selective hydrogenation of ketones to alcohol using acetophenone hydrogenation as model reaction.Systematic investigations demonstrated that unsupported Pd nanocrystals have no catalytic activity for acetophenone hydrogenation.However,oxidized Pd species were catalytically highly active for acetophenone hydrogenation.The catalytic activity decreased with the decreased oxidation state of Pd.This work provides insights into the hydrogenation mechanism of ketones but also other unsaturated compounds containing polar bonds,e.g.,nitrobenzene,N-benzylidene-benzylamine,and carbon dioxide.

Catalytic Aerobic Oxidation of Acetaldehyde over Keggin-type Molybdovanadophosphoric Acid/SBA-15 under Ambient Condition

Keggin-type molybdovanadophosphoric acids （HPA）, H4PMo11VO40 （1）, H5PMo10V2O40 （2） and H6PMo9V3O40 （3） were anchored onto γ-aminopropyltriethoxysilane （APTS） aminosilylated silica mesoporous SBA-15 through acid-base neutralization and the resulting HPA/APTS/SBA-15 were characterized by BET, TEM, XRD, ICP, FFIR and ^31p MAS NMR. The characterization results indicate that the Keggin-structure of these HPAs is preserved within the mesoporous silica host. The samples were tested for catalytic aerobic oxidation of acetaldehyde heterogeneously in liquid phase under ambient condition. The electrostatic force between heteropoly acid and amino groups grafted on the silica channel surface leads to strong immobilization of HPA inside SBA-15 which is against the leaching during the reaction. The good catalytic performance and easy recycle of these catalysts make them as potential environmental friendly catalysts for elimination of indoor air pollutants.

加入Si粉对低碳铝镁碳材料性能的影响

以82%（质量分数,下同）的电熔白刚玉（3-0.088mm）、10%的镁铝尖晶石（≤0.088mm）、5%的氧化铝微粉（d50=2.4μm）、3%的电熔镁砂（≤0.088mm）以及占总粉体质量5%的酚醛树脂结合剂为基础配方,分别用2%、4%、6%的Si粉（≤0.088mm）取代等量的白刚玉,分别于1400℃3h和1600℃3h埋炭烧成后制备了不同Si粉含量的低碳铝镁碳材料,对材料的显气孔率、体积密度、强度、抗热震性、抗氧化性及抗渣性进行了检测,并借助XRD、SEM和EDAX研究了材料的物相组成和显微结构。结果表明：随着Si粉加入量的增加,经1400℃3h和1600℃3h埋炭烧成后,材料的体积密度逐渐降低,显气孔率增大,耐压强度明显提高（但Si粉加入量超过4%后材料的耐压强度有所降低）,高温抗折强度（1400℃）逐渐提高,抗热震性得到改善,抗氧化性能增强,抗渣性能明显提高。材料性能的这种变化主要同材料中酚醛树脂的残碳与Si粉原位生成β-SiC,以及材料气孔中有Mg-Si-Al-O-N物相生成相关。

Preparation and evaluation of aminopropyl-functionalized manganese-loaded SBA-15 for copper removal from aqueous solution

A novel material, aminopropyl-functionalized manganese-loaded SBA-15（NH2-Mn-SBA-15）, was synthesized by bonding 3-aminopropyl trimethoxysilane（APTMS） onto manganeseloaded SBA-15（Mn-SBA-15） and used as a Cu2＋adsorbent in aqueous solution. Fourier transform infrared spectroscopy（FT-IR）, X-ray diffraction spectra（XRD）, N2adsorption/desorption isotherms, high resolution field emission scanning electron microscopy（FESEM）and X-ray photoelectron spectroscopy（XPS） were used to characterize the NH2-Mn-SBA-15.The ordered mesoporous structure of SBA-15 was remained after modification. The manganese oxides were mainly loaded on the internal surface of the pore channels while the aminopropyl groups were mainly anchored on the external surface of SBA-15. The adsorption of Cu2＋on NH2-Mn-SBA-15 was fitted well by the Langmuir equation and the maximum adsorption capacity of NH2-Mn-SBA-15 for Cu2＋was over two times higher than that of Mn-SBA-15 under the same conditions. The Elovich equation gave a good fit for the adsorption process of Cu2＋by NH2-Mn-SBA-15 and Mn-SBA-15. Both the loaded manganese oxides and the anchored aminopropyl groups were found to contribute to the uptake of Cu2＋. The NH2-Mn-SBA-15 showed high selectivity for copper ions. Consecutive adsorption–desorption experiments showed that the NH2-Mn-SBA-15 could be regenerated by acid treatment without altering its properties.

碳硅复合固体酸催化剂的制备及其催化性能研究

以氧化硅(SBA-15)为载体,蔗糖为碳源,通过碳化、磺化法制备碳硅复合固体酸催化剂,利用XRD、BET、TG等对催化剂进行表征分析,并将其用于催化松节油水合反应,考察催化剂制备条件和水合反应条件对产品中松油醇含量的影响.适宜的催化剂制备条件为:碳用量40%,碳化时间15 h,磺化时间9 h.最佳催化合成工艺条件为:催化剂用量0.3 g,n(α-蒎烯):n(一氯乙酸):n(H_2O)=1:1.5:1.5,反应温度70℃,反应时间3 h,在该反应条件下,α-蒎烯转化率为100%,产物中α-松油醇含量为85.81%.

Preparation,Characterization and Catalytic Activity of Palladium Nanoparticles Embedded in the Mesoporous Silica Matrices

Novel in-situ reduction approach was applied for the synthesis of palladium nanoparticles in the pores of mesoporous silica materials with grafted siliconhydride groups. Matrices possessing different structural properties (MCM-41, SBA-15 and Silochrom) were used. Samples were studied by nitrogen adsorption-desorption method, low-angle X-ray diffraction, transmission electron microscopy (TEM) and FT-IR/PAS spectroscopy. The temperature-programmed oxidation (TPO) and reduction (TPR) methods were applied to examine reducibility of palladium species. Palladium containing catalysts were tested in methane oxidation reaction. It was demonstrated that relatively large pores in SBA-15 type silica facilitated formation of well-dispersed palladium nanoparticles confined in the pores channels. In the case of MCM-41 support, metallic palladium nanoparticles were formed on the external surface. The obtained materials showed high catalytic activity. Lower activity of the samples containing small crystallites located in the pore volume at high temperatures was related to worse accessibility of active sites to the reation mixture.

Effect of Structural Properties of Mesoporous Co3O4 Catalysts on Methane Combustion

Highly ordered 2D and 3D-Co3O4 catalysts were prepared using SBA-15 and KIT-6 as templates. Na- no-Co304 catalyst was obtained by calcination of cobalt nitrate as a comparison. The BET surface area of nano- CO304, 2D-Co3O4 and 3D-Co3O4 catalysts was 16.2, 63.9 and 75.1 mE/g, respectively. All the catalysts were tested for the total combustion of methane and their catalytic performance was in the order of 3D-Co3O4（T90=355℃）〉 2D-CoaO4（T90=383℃）〉nano-Co3O4（T90=455℃）. It was also found that the order of the areal specific reaction rates for the combustion of methane followed the same order of total activity. The characterization result demonstrates that enhanced catalytic performance of methane of the 2D-Co3O4 and 3D-Co3O4 catalysts is due to their pronounced reducibility and abundant active Co3O4 species, which was caused by the preferential exposure of {220} crystal planes in 3D-Co3O4 and 2D-Co3O4 catalysts compared to the nano-Co3O4.