DALTON TRANSACTIONS
·
2022
·Vol. 51
·期 48
·18562-18571
·
IF 4.569
Han Zhao,Longchun Bian,Junchen Du,Yunkun Zhao
The Pd distribution and the CeO2–Al2O3 combination are among the decisive factors for the performance of commercial three-way catalysts. Generally, the sufficient doping of Pd into ceria-based oxides and the intimate interaction between CeO2 and Al2O3 could both benefit the three-way catalytic reactions. However, in the present work, the moderate doping of Pd into CeO2 and less intimate CeO2–Al2O3 interaction were found to be responsible for the much higher catalytic activity (the decrease in T50 was 52, 119, or 55 °C for C3H6, CO, or NO) in PdCe/Al2O3-CP than PdCe/Al2O3-Imp, for which the Pd and Ce species were co-loaded onto Al2O3 through the co-precipitation or impregnation method, respectively. It was intriguing to find that the co-precipitated PdCeOx in PdCe/Al2O3-CP showed less sufficient doping of Pd into CeO2 than the co-impregnated PdCeOx in PdCe/Al2O3-Imp; as a result, both a higher fraction of highly active metallic Pd and a higher Pd dispersion were realized in PdCe/Al2O3-CP. Moreover, due to the less intimate CeO2–Al2O3 interaction, specifically the less severe penetration of the Pd and Ce species into Al2O3, PdCe/Al2O3-CP showed higher Pd dispersion, specific surface area, pore volume and size than PdCe/Al2O3-Imp. The presence of more abundant reactive Pd0, and the higher accessibility of the active Pd and CeO2 sites, together with improved redox properties and enriched oxygen vacancies contributed much to the enhanced three-way catalytic activity of PdCe/Al2O3-CP. Additionally, simultaneously optimizing the Pd distribution and the CeO2–Al2O3 combination in a single step, as reported in this work, is also highly desirable in industry.
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高影响因子
APPLIED CATALYSIS A-GENERAL
·
2022
·
IF 5.723
Yue Li,Huan Ren,Daolai Sun,Xinqiang Zhao,Satoshi Sato
Liquid-phase catalytic hydrodeoxygenation of 1,2-decanediol (1,2-DDO) to form 1-decanol was performed over various non-noble metal-loaded acidic catalysts, and Cu loaded on amorphous SiO 2 -Al 2 O 3 exhibited a high catalytic activity for the formation of 1-decanol. A high 1-decanol selectivity of 84.7% with a complete 1,2-DDO conversion was obtained within only 15 min over the Cu/SiO 2 -Al 2 O 3 at 250 °C under 10 MPa H 2 pressure. The temperature at 250 °C and the H 2 pressure higher than 3 MPa were conducive to the efficient production of 1-decanol from 1,2-DDO. In contrast to the previously reported noble metal catalysts, Cu/SiO 2 -Al 2 O 3 required a relatively high reaction temperature, while an extremely high 1-decanol productivity of 78 mmol g cat −1 h −1 could be achieved. Meanwhile, the hydrodeoxygenation of 1,2-decanediol over Cu/SiO 2 -Al 2 O 3 proceeded via a reaction mechanism in which decanal was formed as the intermediate. In addition, the Cu/SiO 2 -Al 2 O 3 catalyst was reusable at least five times without serious deactivation.
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Advanced Electronic Materials
·
2022
·Vol. 8
·期 9
·2200319
·
IF 7.633
Zhiguo Jiang,Weikun Wen,Zhijian Zhong,Liping Xia,Fangliang Gao,Yong Zhang,Jiang Wu,Said Nasir Khisro,Aiyun Zha,Qingbin Zha,Xinman Chen
Intrigued by the artificial intelligence and brain-like neural networks, the photoelectronic neuromorphic devices that can simulate synaptic functions have been attracting wide attention. However, equalizing excitation-inhibition has been seldom artificially realized despite its fundamental feature in a biological system. In this work, an artificial synapse is proposed based on a sandwiched Ag/Al 2 O 3 /graphene/ITO photodetector. The device exhibits a special ambipolar photoresponse at the millivoltage as a result of the interfacial trapping effects. Under the coupled light and electrical stimulus, the synaptic excitatory, inhibitory signals and their recovery are emulated on a single device via the positive and negative photoresponse, respectively. Further, the biologically dynamic balance of excitation and inhibition is reproduced on a simple analogous system integrating multiple photoelectronic synaptic cells. These remarkable results provide a potential foundation for building hardware units with neuromorphic architecture to mimic the complex human brain functionalities.
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CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Xianfu Chen,Chaowen Dai,Tianyu Zhang,Peng Xu,Wei Ke,Jian Wu,Minghui Qiu,Kaiyun Fu,Yiqun Fan
Membrane separation has been proven to be a promising technology for waste-oil purification. However, the efficient preparation of hydrophobic and strong membrane materials has always been one of the bottlenecks and the object of research focus in the field. Here, we developed an efficient construction method for preparing a hydrophobic membrane with a robust polytetrafluoroethylene (PTFE) top layer. The macroporous ceramic substrate was applied instead of the ceramic membrane as the support of the PTFE layer. Meanwhile, two-dimensional graphene oxide was introduced to partially pre-fill the large pores on the surface of the substrate. Resultantly, the binding depth between the membrane layer and the substrate was properly tailored. The excessive infiltration of the PTFE membrane layer was avoided, and there was a strong binding between the membrane layer and the ceramic substrate. The effects of the graphene oxide and PTFE loadings and thermal treatment on the microstructure and performance of the composite membrane were systematically studied. The optimized PTFE/alumina composite membrane exhibited a water contact angle of ∼ 135°, an average pore size of ∼ 200 nm, and a layer thickness of 6.5 μm. Additionally, the prepared composite membrane exhibited excellent separation performance for emulsified water and particle suspensions in oil.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2022
·
IF 7.139
Yang Xu,Yingying Zhu,Pengfei Shen,Geng Chen,Xinbao Li
An improved method for hydrogen production by the steam reforming of phenol over novel fly ash-based catalysts is investigated. The Ni/Al 2 O 3 -ash catalysts are prepared by an equal-volume impregnation method and characterized by XRD , FESEM , BET and H 2 -TPR techniques. The effects of various process parameters including mixing ratio of fly ash, temperature, support, gas hourly space velocity (GHSV) and steam-to-carbon molar ratio (S/C) on the catalytic activity are investigated. The results show that fly ash mixing at 50 wt% and choosing γ-Al 2 O 3 as the support own the best performance. A maximum hydrogen yield of 83.8% is achieved at 450 °C with a S/C of 10 and a GHSV of 4968 h −1 with a maximum phenol conversion of 98.6%. The stability of the Ni-ash1-γA1 catalyst is further investigated and it is shown to continuously and stably react for more than 20 h at 450 °C with excellent catalytic reaction stability.
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Crystals
·
2023
·Vol. 13
·期 8
·1261
·
IF 2.7
Zhen Pei,Haixiao Huang,Xingzhong Guo,Jinming Zhang,Mingxing Chen
MgO–Al2O3–SiO2(MAS) glass–ceramics with controllable crystalline phases were successfully prepared using the melting method followed by heat treatment. The effects of the main components of glass on the crystallisation kinetics, nucleation, crystallisation and properties of glass–ceramics were investigated in detail. As the Al2O3and MgO contents increase and SiO2content decreases, the crystallisation peak temperature and activation energy of MAS glass decrease, while the crystal growth tends to follow a homogeneous nucleation crystallisation. The MAS glass nucleation temperature and time increase with higher concentrations of Al2O3and MgO and with a lower SiO2concentration. Mg2(Al4Si5O18) indialite and MgAl2O4spinel precipitate simultaneously in the MAS glass after crystallisation; the relative proportion of crystalline phases is related to the composition and crystallisation temperature. A higher SiO2content allows the formation of a dominant indialite phase, while higher MgO and Al2O3contents promote the formation of a dominant spinel phase. The MAS glass ceramic with a greater indialite phase has good dielectric properties with a dielectric constant of 6.499 and dielectric loss of 0.0064, while that of a higher spinel phase possesses improved mechanical properties, with a Vickers hardness of 715 Hv and a bending strength of 244.9 MPa.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Yang Li,Yuchang Qing,Haoyang Yao,Hailong Xu,Hongjing Wu
High-performance microwave absorption coatings are critically required in the stealth defense system of military platforms. Regrettably, just optimizing the property but neglecting the application feasibility seriously inhibits its practical application in the field of microwave absorption. To face this challenge, the Ti 4 O 7 /carbon nanotubes (CNTs)/Al 2 O 3 coatings were successfully fabricated by a plasma-sprayed method. For the different oxygen vacancy-induced Ti 4 O 7 coatings, the enhanced ε' and ε'' values in the frequency of X-band is due to the synergistic manipulation of conductive path, defects and interfacial polarization. The optimal reflection loss of Ti 4 O 7 /CNTs/Al 2 O 3 sample (0 wt% CNTs) is −55.7 dB (8.9 GHz of 2.41 mm), while the electromagnetic interference shielding effectiveness of Ti 4 O 7 /CNTs/Al 2 O 3 sample (5 wt% CNTs) increases to 20.5 dB as the enhanced electrical conductivity. In special, the flexural strength of Ti 4 O 7 /CNTs/Al 2 O 3 coatings first increases from 48.59 MPa (0 wt% CNTs) to 67.13 MPa (2.5 wt% CNTs) and then decreases to 38.31 MPa (5 wt% CNTs), demonstrating that an appropriate amount of CNTs evenly dispersed in the Ti 4 O 7 /Al 2 O 3 ceramic matrix can effectively play the role of CNTs as the strengthening phase of the coatings. This research will provide a strategy by tailoring synergistic effect of dielectric loss and conduction loss for oxygen vacancy-mediated Ti 4 O 7 material to broaden the application of absorbing or shielding ceramic coatings.
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2023
·Vol. 47
·期 21
·10397-10408
·
IF 3.3
Ning Gao,Xuanyu Gu,Jining Liu,Mengjie Fan,Yingwen Chen
At present, it is challenging to improve the activity and humidity resistance of ozone catalysts. Herein, an integrated MnOx–Al2O3 aerogel was prepared by a sol–gel method in this study, and its application in catalytic ozonation of toluene was explored preliminarily. Compared with the MnOx–SiO2 aerogel and impregnation catalysts (MnOx–silicalite-1 and MnOx–γ-Al2O3), the MnOx–Al2O3 aerogel exhibited superior performance in toluene removal and enhanced ozone utilization efficiency under optimal conditions (room temperature, O3 : C7H8 = 14 : 1, GHSV = 45 000 h−1 and 120 ppm C7H8). After reacting for 360 min, the 5 wt% MnOx–Al2O3 aerogel still showed stable catalytic ability, with the efficiency of toluene removal and ozone degradation maintained at 64.1% and 62.7%, respectively. Based on SEM characterization, the MnOx–Al2O3 aerogel demonstrated low MnOx agglomeration. From XPS and NH3-TPD analyses, it was found that the catalyst had a high content of Mn3+/Mn, Oβ/O, oxygen vacancies and acid sites, which was positively related to ozone degradation. Among them, an increase in the number of weak acid and moderately strong acid sites could prolong the life of active oxygen, which was the key to promoting the deep oxidation of toluene effectively. In addition, the MnOx–Al2O3 aerogel exhibited remarkable load-adjustability and humidity resistance. Therefore, the development of aerogel catalysts for catalytic ozonation of toluene is an effective strategy to alleviate the current ozone catalyst problem.
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高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2021
·Vol. 168
·期 10
·103508
·
IF 4.316
Donghua Tian,Mingyong Wang,Jingxiu Wang,Jiguo Tu,Shuqiang Jiao
USTB technology is widely considered as a low-cost and environmentally-friendly method for titanium extraction from a consumable TiCxOy anode. It is expected to directly prepare TiCxOy by selective carbothermal reduction of titanium ores, not pure TiO2. However, impurities in titanium ores, particularly Al2O3, may affect the electrochemical dissolution of TiCxOy and Ti extraction. In this work, the effects of Al2O3 impurity on the preparation and dissolution behaviors of Ti2CO are studied. It is found that the existence form of Al2O3 is not changed during carbothermal reduction. With the increase of Al2O3 content, the conductivity of Ti2CO anode slightly decreases from 143.1 to 131.6 S cm−1 and the anodic polarization curves of Ti2CO@Al2O3 shifts to the positive direction due to the increase of dissolution resistances. Al2O3 in Ti2CO@Al2O3 anode will drop into molten salts to form anode slime during USTB process. On both liquid Zn and solid nickel cathodes, Ti is electrodeposited, which is not affected by Al2O3 impurity. Therefore, it is confirmed that typical Al2O3 impurity has no obvious effect on the electrochemical dissolution of Ti2CO anode and Ti extraction. The advanced USTB process is expectedly developed by the selective carbothermal reduction of titanium ores to prepare Ti2CO anode.
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Molecular Catalysis
·
2023
·
IF 4.6
Bowen Wu,Yixi Chen,Mingtai Liu,Yi Tang,Gengfeng Zheng,Linping Qian
The surface properties of CoMg/Al 2 O 3 were evaluated in the aerobic oxidation of p -cresol. The surface interaction is enhanced greatly after Co and Mg impregnation with the mole ratio of Co/Mg from 2 : 1 and 2 : 3. The strongest interaction for the nonpolarity and benzene ring was found on CoMg/Al 2 O 3 with Co/Mg of 2 : 3. But for the interaction with p -π group bonding with negative anion, the highest value appears on the catalyst with the Co/Mg of 2 : 2. In aerobic oxidation of p -cresol, the conversion is significantly increased with Co addition and reaches around 60 % after 24 h' reaction at 338 K. The highest selectivity of p -hydroxybenzaldehyde of 99 % is achieved on Al 2 O 3 with the co-impregnation mole ratio of Co/Mg of 2 : 2. It is suggested that medium adsorption of the reactants and strong stabilization of the intermediates facilitate the aerobic oxidation of p -cresol to p -hydroxybenzaldehyde.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Binbin Zhao,Jieqi Zou,Chen Chen,Qian He,Qiong Tang,Lei Liu,Jinxiang Dong
Pt-WO x -based catalyst has been considered as a promising candidate for the conversion of glycerol to 1,3-propanediol, but the catalytic performance was quite susceptible to the structure and chemical state of WO x species. Herein, we develop a facile approach to construct the single-atom tungsten-doped Al 2 O 3 with a low chemical state through in-situ migration of WO 3 nanoparticles under the H 2 atmosphere. The characterization results demonstrated that the tetrahedral W 5+ could disperse and stabilize the platinum species more effectively, and exhibited stronger interaction with platinum than the octahedral W 6+ species. The enhanced catalytic performance is attributed to the rich oxygen defects on in-situ generated tetrahedral WO x on the catalyst, which facilitated the construction of Pt-WO x interface and strengthened the synergetic effects between them. The analysis of structure-performance correlation revealed that the mono-dispersed tetrahedral W 5+ species [(-O-) 3 W(=O)] played a pivotal role in tuning catalyst acidity and improving the catalytic performance, which assists the adsorption of glycerol and captures H for in-situ formation of Brønsted acid site, and ultimately affected the selectivity toward 1,3-PDO and catalytic activity.
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NEW JOURNAL OF CHEMISTRY
·
2023
·Vol. 47
·期 39
·18450-18460
·
IF 3.3
Yao Shen,Fang Lin,Kang Wang,Xitao Wang
CaO-doped γ-Al2O3 beads were prepared by an alginate assisted sol–gel method, followed by grafting with alkyl groups and impregnation of NbCl5 to construct multi-functionalized γ-Al2O3 beads for efficient catalytic conversion of glucose to 5-hydroxymethylfurfural (5-HMF). Doping with CaO improved the binding capacity of the catalyst with glucose and increased the Lewis acid amount. However, a high CaO content would cover the Lewis acid sites of γ-Al2O3, resulting in a lower isomeric conversion of glucose to fructose. When the C8–Ca(10%)–γ-Al2O3 catalyst was loaded with Nb2O5, intermediate fructose was consumed rapidly resulting in complete conversion of glucose, which indicated that conversion of glucose to 5-HMF involved the isomeric conversion of glucose to fructose followed by dehydration of fructose to 5-HMF. This was necessary to balance hydrophilic isomerization reactions with restraining the rehydration of 5-HMF by hydrophobic modification. This is similar to the reaction in which a medium with a certain amount of water was beneficial for glucose isomerization. Under the synergistic effect of Lewis acid provided by γ-Al2O3 and Brønsted acid offered by Nb2O5, C8–Ca(10%)–γ-Al2O3–Nb(3%), a glucose conversation rate of 100% and the highest yield of 5-HMF (68.4%) were achieved in the reaction medium with a dimethylsulfoxide/H2O (V/V) ratio of 4 : 1, a catalyst amount of 33 mg, a reaction temperature of 140 °C and a reaction time of 4 h.
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