Frontiers in Chemistry
·
2022
·
IF 5.545
Huang Meng,Huang Wenbin,Li Anqi,Yang Han,Jia Yijing,Yu Zhiqing,Xu Zhusong,Wang Xiaohan,Zhou Yasong,Wei Qiang
Experiments were carried out to research the different contents of Ga2O3 modification effects on the hydrodesulfurization (HDS) performance of 4,6-dimethyldibenzothiophene (4,6-DMDBT) catalyzed by the stepwise impregnation method. Characterization techniques such as XRD, BET, HRTEM, NH3-TPD, and Py-FTIR were performed to determine the effects of each modification of the catalyst by Ga on the properties of the prepared supports and catalysts. The catalytic effect of gallium is reflected in the fact that the empty d-orbitals of Ga elements participate in the formation of molecular orbitals in the active center and change their orbital properties, thus generating a direct desulfurization active phase suitable for complex sulfides for endpoint adsorption. The characterization results indicated that the introduction of Ga2O3 with appropriate content (2 wt.%) promoted Ni and Mo species to disperse uniformly and doping of more Ni atoms into the MoS2 crystals, which also increased the average stacking number and the length of MoS2. As a result, more NiMoS active phases were favored to form in the system. The specific surface area and the amounts of acid sites were increased, facilitating the adsorption of reactant molecules and the HDS reactions. The HDS results also suggested the effects of Ga modification play a very important role in the catalytic performance of the corresponding catalysts. The catalyst Ga–Ni–Mo/Al2O3 exhibited the highest conversion rate towards 4,6-DMDBT HDS when the amount of Ga2O3 loading was 2 wt.% with an LHSV of 2.5 h−1 at 290°C and Ga modification also can effectively improve the direct desulfurization (DDS) route selectivity in varying degrees.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 12
·2753
·
IF 4.2
Yongzhen Gao,Wenjing Yi,Jingyi Yang,Kai Jiang,Tao Yang,Zhihan Li,Meng Zhang,Zhongyi Liu,Benlai Wu
The selective hydrogenation of the biomass platform molecule furfural (FAL) to produce furfuryl alcohol (FA) is of great significance to alleviate the energy crisis. Cu-based catalysts are the most commonly used catalysts, and their catalytic performance can be optimized by changing the preparation method. This paper emphasized the effect of calcination atmosphere on the performance of a Cu/Al2O3catalyst for the selective hydrogenation of FAL. The precursor of the Cu/Al2O3catalyst prepared by the ammonia evaporation method was treated with different calcination atmospheres (N2and air). On the basis of the combined results from the characterizations using in situ XRD, TEM, N2O titration, H2-TPR and XPS, the Cu/Al2O3catalyst calcined in the N2atmosphere was more favorable for the dispersion and reduction of Cu species and the reduction process could produce more Cu+and Cu0species, which facilitated the selective hydrogenation of FAL to FA. The experimental results showed that the N2calcination atmosphere improved the FAL conversion and FA selectivity, and the FAL conversion was further increased after reduction. Cu/Al2O3-N2-R exhibited the outstanding performance, with a high yield of 99.9% of FA after 2 h at 120 °C and an H2pressure of 1 MPa. This work provides a simple, efficient and economic method to improve the C=O hydrogenation performance of Cu-based catalysts.
研究领域:
催化化学
·
能源化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Sciences
·
2021
·
IF 5.565
Chang Cui,Yan Zhang,Wenpo Shan,Yunbo Yu,Hong He
Alumina supported Pd catalyst (Pd/Al 2 O 3 ) is active for complete oxidation of methane, while often suffers transient deactivation during the cold down process. Herein, heating and cooling cycle tests between 200 and 900°C and isothermal experiments at 650°C were conducted to investigate the influence of NO x on transient deactivation of Pd/θ-Al 2 O 3 catalyst during the methane oxidation. It was found that the co-fed of NO alleviated transient deactivation in the cooling ramp from 800 to 500°C, which was resulted from the in situ formation of NO 2 during the process of methane oxidation. Over the Pd/θ-Al 2 O 3 , thermogravimetric analysis and O 2 temperature programmed oxidation measurements confirmed that transient deactivation was due to the decomposition of PdO particles and the hysteresis of Pd reoxidation, while the metal Pd entities were less active for methane oxidation than the PdO ones. CO pulse chemisorption and scanning transmission electron microscopy characterizations rule out the NO 2 effect on Pd size change. Powder X-ray diffraction and X-ray photoelectron spectroscopy characterizations were used to obtain palladium status of Pd/θ-Al 2 O 3 before and after reactions, indicating that in lean conditions at 650°C, the presence of NO 2 increases the content of active PdO on the catalyst surface, thus benefits methane oxidation. Homogeneous reaction between CH 4 , O 2 , and NO x may be partially responsible for the alleviation above 650°C. The interesting research of alleviation in transient deactivation by NO x , the components co-existing in exhausts, are of great significance for the application.
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Wenjie Zhang,Jing Zhao,Linfeng Wang,Guofu Liu,Dekui Shen,Huiyan Zhang
The pyrolytic reforming of toluene to hydrogen and CNTs over the commercial and self-prepared Al 2 O 3 loaded with Fe through the impregnation method is investigated in a fixed bed reactor under the temperature from 600 °C to 800 °C. The physicochemical properties of Fe–Al 2 O 3 catalysts and Al 2 O 3 supports were characterized by XPS, H 2 -TPR, HRTEM and H 2 -pulse chemisorption . The reforming process over the catalyst of Fe loaded on self-prepared Al 2 O 3 gives the excellent H 2 yield of 27.8 mmol/(g-Fe) and graphite yield of 82.6 wt%, which is much higher than those from that over the catalyst of Fe loaded on the commercial Al 2 O 3 . It is evidenced by H 2 -pulse chemisorption that 5.1 % of Fe 0+ dispersion over the commercial Al 2 O 3 with mainly-exposed (110) facet while 11.2 % of Fe 0+ dispersion over self-prepared Al 2 O 3 with mainly-exposed (111) facet were obtained. The adsorption energy of iron cluster (Fe 4 ) with Al 2 O 3 (111) facet was estimated to be −14.5 eV through the DFT simulation, which is notably higher than that of iron cluster (Fe 4 ) with Al 2 O 3 (110) facet as −9.1 eV. With regard to the MD simulation along with XRD analysis of the Fe 3 C crystallite , Fe 0+ particles can be prominently molten at the high Fe 0+ dispersion over Al 2 O 3 facet, promoting the carbon solubility for the assembly of multi-wall CNTs without the deposition of unwanted amorphous carbon .
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2025
·
IF 7.5
Hong-Hui Gong,Xian-Yong Wei,Wen-Long Mo,Zhi-Min Zong,Guang-Hui Liu,Pei Liu,Kun-Peng Jiao
NiCs/Al 2 O 3 with medium-strong alkaline and the contents of Ni and Cs of 26.55 wt% and 0.02 wt%, respectively, was prepared by a three-step method and characterized with multiple tools. Oxydibenzene (ODB) and benzyloxybenzene (BOB) were used as low-rank coal-related model compounds and their catalytic hydroconversion (CHC) were investigated over NiCs/Al 2 O 3. Under mild conditions (MCs), NiCs/Al 2 O 3 can effectively activate H 2 to biatomic active hydrogen (H···H) and part of H···H can be effectively split to relative mobile H - and immobile H + on the NiCs/Al 2 O 3 surface. Both ODB and BOB can be completely converted and full hydrogenation (FH) of the benzene ring (BR) in −O-BR is the first step for the CHC of both ODB and BOB via H···H transfer to the BR under MCs. Subsequently, H - transfer to an ipso -carbon (IC) in the resulting oxydicyclohexane from the FH of ODB cleaves an −O-CH< bond to produce cyclohexane (CH I ) and cyclohexyloxy anion (CHOA), which abstracts H + from H···H to afford cyclohexanol (CH II ) followed by H - transfer to the IC in CH II and subsequent HO – release to yield CH I . As a result, CH I is the only final product from the CHC of ODB. In contrast, H - transfer preferentially proceeds to the carbon atom in the –CH 2 - of the resulting benzyloxycyclohexane from the FH of the BR in −O-BR of BOB to produce toluene and CHOA followed by the FH of toluene to get methylcyclohexane and the H + abstraction by CHOA from H···H to obtain CH II . Moreover, NiCs/Al 2 O 3 shows a distinguished recyclability and repeatability.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2019
·
IF 4.888
Lei Zhang,Hao Wang,Chengguang Yang,Xiaopeng Li,Jian Sun,Hui Wang,Peng Gao,Yuhan Sun
The present work reports on the promoting effects of rare earth elements (La, Ce and Y) to FeK/Al 2 O 3 catalysts on liquid hydrocarbons from CO 2 hydrogenation. The addition of La, Ce and Y can both improve the selectivity of C 5+ hydrocarbons and reduce the selectivity of CH 4 . The C 5+ selectivity can enhance to about 60 % with CH 4 selectivity of around 11 % at CO 2 conversions above 20 %. N 2 adsorption–desorption, in situ XRD, H 2 –TPR, CO 2 /H 2 –TPD, HRTEM and XPS are used to characterize the FeK/Al 2 O 3 and FeK/M-Al 2 O 3 (M = La, Ce, Y) catalysts. The results show that the introduction of rare earth elements into the FeK/Al 2 O 3 catalyst obviously reduces the adsorption of H 2 , which suppresses the CH 4 formation. On the other hand, rare earth elements also promote the adsorbed CO 2 species, which leads to the enhanced liquid hydrocarbons selectivity. Finally, the tailored CO 2 /H 2 ratio of CO 2 and H 2 adsorption on the catalyst surface can influence the catalyst activity and the product selectivity evidently.
研究领域:
催化化学
·
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 54
·48737-48744
·
IF 3.289
Danfeng Hou,Jiayu Xin,Xingmei Lu,Xiaonan Guo,Huixian Dong,Baozeng Ren,Suojiang Zhang
1,4-Cyclohexanedimethanol (CHDM) is a highly valued and widely used monomer in the polymer industry. Bis(2-hydroxyethylene terephthalate) (BHET), the product of glycolysis of waste PET, is an excellent raw material for the preparation of CHDM. Herein, a series of monometallic, bimetallic and trimetallic supported catalysts were prepared for the one-pot conversion of BHET into CHDM by the impregnation method and good performance was found over trimetallic RuPtSn/Al2O3 catalysts containing various active sites to catalyze the hydrogenation of the phenyl and carbonyl groups. The influences of various reaction parameters including temperature, pressure and time on the hydrogenation reaction were studied, and 100% conversion and 87.1% yield of CHDM were obtained with the trimetallic supported catalyst with Ru/Sn 1.5. Moreover, through the comparison between various methods for the preparation of CHDM, the conversion of BHET into CHDM by the one-pot method is considered one of the most competitive methods.
研究领域:
化学工程
·
材料科学
·
催化反应
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 44
·期 2
·549-555
·
IF 3.069
Jianjian Wang,Qingjie Tang,Shiwei Jin,Yanxin Wang,Ziliang Yuan,Quan Chi,Zehui Zhang
The development of new heterogeneous non-noble catalytic systems for the selective hydrogenation of nitriles into primary amines is a challenging task. In this study, a mesoporous Al2O3 supported Ni catalyst (denoted as Ni/Al2O3-600, where 600 represents the reduction temperature) demonstrated a high catalytic activity for the hydrogenation of nitriles under mild conditions (60–80 °C and 2.5 bar H2) with ammonia as the additive. This catalytic system has a wide substrate range and the Ni/Al2O3 catalyst demonstrated a good tolerance to other functional groups, which was possibly due to its high catalytic activity under mild conditions. A plausible reaction pathway was proposed for the hydrogenation of nitriles into primary amines, and it was found that ammonia played a great role in the enhancement of the selectivity of primary amines by the inhibition of the side reaction to generate secondary amines. In addition, the Ni/Al2O3-600 catalyst could be reused five times without activity loss through convenient magnetic recovery.
研究领域:
催化化学
·
有机合成
✓ 已验证
DOI
高影响因子
ChemCatChem
·
2024
·
IF 3.8
Huan Yang,Xu Wang,Haowei Wang,Ya-Dong Xie,An-Hui Lu
Graphical The Sn species doped by coprecipitation with Al precursor introduces additional acidic sites on Sn-doped alumina, which after loading with Pt species exhibits superior reactivity and stability for propane dehydrogenation. Alumina-supported PtSn catalysts have been industrialized as the major catalysts for propane dehydrogenation, where Sn serves as an essential promoter. Herein, we synthesized a variety of Sn-doped alumina supports by regulating the precipitation order of Sn and Al precursors as follows: Sn precursor precipitated before Al, coprecipitated with Al, precipitated immediately after Al, or precipitates after 2 h of Al. The effect of Sn promoter on the surface acidic properties of alumina and, ultimately, on propane dehydrogenation was further investigated. The Sn species introduced by coprecipitation in alumina created additional surface strong acid sites, attributed to more Sn 4+ species on the surface, which are able to remain stable during the subsequent treatment. Consequently, the coprecipitated Sn species in the corresponding catalyst donate more electrons to Pt and reduce the metal particle size. As a result, the catalyst with Pt supported on the coprecipitated support (Sn+Al) exhibits superior initial propane conversion (43.2%) and stability ( k d = 0.035 h −1 ). This study provides new insight into the interaction between the two key components, tin promoter and alumina support, of Pt/Sn-Al 2 O 3 catalysts.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 13
·2959
·
IF 4.2
Hejingying Niu,Jinhua Ma,Lina Gan,Kezhi Li
In this study, a PtSn/Al2O3catalyst with bimetallic uniform distribution in the sphere was synthesized. The PDH performance and characterization analyses, such as with FTIR, XPS, and NH3-TPD, were investigated. The effects of acid on the PDH performance were analyzed. Citric acid (CA) acted as a competing adsorbent in the preparation process of the PtSn/Al2O3catalyst to synthesize the uniform catalyst. Water washing and alkali-treated samples were also studied. SEM line scanning revealed that increased the apparent concentration of Pt metal from 0.23 to 0.30 with citric acid. In contrast to the fresh PtSn/Al2O3catalyst, the addition of citric acid increased the PDH selectivity from 74% to 93%. After alkali or water washing treatments, the catalyst’s selectivity further increased to 96%. Strong acid sites promoted the breaking of C–C bonds during the PDH reaction, resulting in more methane and ethylene byproducts, and decreased catalyst selectivity for fresh PtSn/Al2O3. From the PDH reaction thermodynamic analysis, a relatively sub-atmospheric pressure environment with a lower propane pressure could be the reasonable choice.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of CO2 Utilization
·
2024
·
IF 7.2
Luqman Abdullahi Sani,Haolong Bai,Zifu Xu,Liangliang Fu,Yining Sun,Xiaorui Huang,He Gao,Xuejing Liu,Dingrong Bai,Zhanguo Zhang,Fabing Su,Jiao Liu,Guangwen Xu
Ni/Al 2 O 3 catalysts (noted as Ni/Al-350, Ni/Al-500, and Ni/Al-700, respectively) were synthesized by a facile solution combustion method but at different combustion temperatures (350 °C, 500 °C, and 700 °C, respectively). For comparison, Ni/Al 2 O 3 (noted as Ni/Al-100) was also prepared by the impregnation method and applied in the methanation reaction. The Ni/Al 2 O 3 synthesized at the combustion temperature of 350 °C showed better performance than the others at higher combustion temperatures, and the activity for CO 2 methanation followed an order of Ni/Al-350 > Ni/Al-500 > Ni/Al-700 > Ni/Al-100. The increase in the combustion temperature decreased active sites for the H 2 and CO 2 adsorption, which could be associated with the reduced Ni dispersion and basic sites, thus lowering its activity and increasing its carbon deposition rate.
研究领域:
催化化学
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Cheng Wang,Fengsheng Zhan,Shan Wang,Yi Wei,Jianbing Ji
Methane pyrolysis is a promising sustainable technology for CO 2 -free hydrogen production. However, the development of stable methods for methane pyrolysis to produce hydrogen at lower temperatures has presented significant challenges. This study presents a reaction system that combines molten carbonate with Ni/Al 2 O 3 catalyst and investigates methane pyrolysis using this system in a bubble-cap reactor. Remarkably, this system exhibited a low activation energy of 145.8 kJ per mole, enabling the achievement of a methane conversion of 92.5 % at 580 °C by employing a double-layer bubble cap tray configuration. Furthermore, the system showcases sustained activity for a duration of up to 72 h.
研究领域:
化学工程
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）