APPLIED ENERGY
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2018
·
IF 7.9
Xiaowen Zhang,Helei Liu,Zhiwu Liang,Raphael Idem,Paitoon Tontiwachwuthikul,Mohammed Jaber Al-Marri,Abdelbaki Benamor
The aim of this work is to find a potential way for great decrease in CO 2 capture energy requirement. Here, for the first time, a series of bifunctional Al 2 O 3 /HZSM-5 catalysts (Al-ZSM) were prepared by the combined precipitation ultrasound method and used for the CO 2 desorption process. All the investigated catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), N 2 adsorption–desorption, ammonia and CO 2 temperature programmed desorption (NH 3 /CO 2 -TPD) and pyridine-adsorption infrared spectroscopy (Py-IR). The regeneration behaviors of a 5 M monoethanolamine (MEA) solvent with four Al-ZSM catalysts were studied at an initial CO 2 loading of 0.5 mol CO 2 /mol amine and the temperature of 96 °C. The results reveal that all the catalysts improve the CO 2 desorption performance, the Al-ZSM catalysts show higher catalytic performance than the single catalysts Al 2 O 3 and HZSM-5, and the Al-ZSM can reduce the heat duty by 23.3–34.2% as compared with the catalyst-free test. The use of Al-ZSM in the MEA regeneration process improves the desorption performance by 2–3 times in comparison with the blank run. A possible dual sites mechanism of CO 2 desorption with Al-ZSM is suggested. The excellent performance of Al-ZSM can be attributed to their enhanced Brϕnsted acid sites (BAS), mesopore surface area (MSA) and basic sites, which resulted from the good synergistic reaction between the Al 2 O 3 and HZSM-5, and the base treatment for HZSM-5. Besides, the stability test of the Al-ZSM was conducted. Based on the results, the Al-ZSM demonstrate a superior catalytic performance for the rich amine regeneration process, and present an excellent cyclic stability, explicitly have the potential to be a promising industrial catalyst for CO 2 capture. Furthermore, the dual sites catalytic CO 2 desorption over bifunctional catalysts will open a new path to design better catalysts for the rich amine solution regeneration process to increase the desorption performance, reduce the regeneration energy consumption, and thus further decreasing the operation costs of CO 2 capture.
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COMPOSITES SCIENCE AND TECHNOLOGY
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2018
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IF 5.16
Xiao Zhang,Jian Zheng,Haoming Fang,Yafei Zhang,Shulin Bai,Guansong He
Nature always provides intelligent strategy for developing advanced materials with superior properties. In this study, by cloning the reinforcing mechanisms in nacre , a nacre-inspired Al 2 O 3 /graphene/polyurethane (PU) composite with hybrid hierarchical structure, was successfully fabricated. The structural interlocking interface, together with its excellent force bearing property, leads to exceptional mechanical performance. Compared with pure PU, the bio-inspired, Al 2 O 3 /graphene reinforced PU composite demonstrates a unique improvement in Young's modulus (211%), tensile strength (41%), and compressive modulus (145%). Moreover, the thermal conductivity of Al 2 O 3 /graphene/PU composite reaches to 0.502 W m −1 K −1 , enhanced by 141% compared with pure matrix, showing very high enhancement efficiency, which is attributed to the multilevel aligned structure and multi-contact conductive pathway inside the composite. This design strategy offers a promising approach to handling high mechanical and thermal performance of solid propulsion fuel by synthesizing bio-inspired architecture.
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FUEL
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2015
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IF 3.52
Hao Wang,Zhenyu Yao,Xuchun Zhan,Yan Wu,Min Li
A microwave hydrothermal (MWH) method was used to deposit WO 3 onto ZrO 2 –Al 2 O 3 with various ZrO 2 contents to prepare hydrodesulfurization (HDS) catalysts with high WO 3 loading (23 wt%) close to industrial hydrotreating, for achieving high W dispersion and weak W-support interaction. The catalysts with the same WO 3 and ZrO 2 contents were prepared by a conventional impregnation (IM) method as reference. The effects of catalyst preparation methods and ZrO 2 contents on the catalyst property and dibenzothiophene HDS activity were investigated. The results show that the MWH method leads to highly dispersed octahedrally coordinated W species which are weakly linked on ZrO 2 –Al 2 O 3 and easy to be reduced; no bulk WO 3 crystallites are observed even at high ZrO 2 content (50 wt%). Therefore, it causes better sulfidation and shorter WS 2 slabs. Contrarily, the IM method induces W species to agglomerate into bulk WO 3 crystallites which are poorly dispersed and hard to be reduced, which is further aggravated by ZrO 2 . The HDS activity of the MWH-prepared catalysts significantly increases with ZrO 2 up to 40 wt% ZrO 2 . This catalyst shows 2 times higher rate constant and 1.64 times higher efficiency of HDS than the IM-prepared catalyst with the same ZrO 2 content. For the IM-prepared catalysts, the HDS activity slightly increases at small amount of ZrO 2 (10 wt%) and then decreases drastically.
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CARBOHYDRATE POLYMERS
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2017
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IF 4.811
Tengfei Deng,Yanjuan Wang,Alain Dufresne,Ning Lin
A green gel-casting method was developed by the combination of rod-like cellulose nanocrystals (CNC) and low toxicity monomer N , N -dimethylacrylamide (DMAA), which was proved to be a promising substitute of traditional neurotoxin monomer acrylamide (AM). The hydrophilic nature and homogeneous dispersion of CNC in aqueous suspension ensured the essential compatibility with the hydrosoluble polymerization system, and therefore provided remarkable mechanical enhancement of green body. The bending strength of the green body was highly increased by 68% with the introduction of 0.9 wt‰ CNC. Meanwhile, the fabricated green body exhibited significant improvement in flexibility and elasticity, with the unique bendable and recovery performances after drying treatment at room temperature for 1 h. The computer stimulation by the COMSOL Multiphysics confirmed the special mechanical enhancement effect induced by the presence of highly-crystalline and rigid CNC.
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PubMed
高影响因子
ChemCatChem
·
2017
·Vol. 9
·期 16
·3144-3152
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IF 4.803
Yong Yuan,Shouying Huang,Hongyu Wang,Yifan Wang,Jian Wang,Jing Lv,Zhenhua Li,Xinbin Ma
Graphical Engineered catalysts : A monodisperse nano-Fe 3 O 4 on α-Al 2 O 3 catalyst synthesized by a novel two-step method of thermal decomposition and impregnation shows enhanced activity and stability for the Fischer–Tropsch synthesis to lower olefins. The effects of promoters (K and S) and size are investigated as well. The Fischer–Tropsch synthesis to lower olefins (FTO) is a desirable nonpetroleum-based route to produce basic chemicals. A novel two-step method was applied to synthesize iron-based supported catalysts, which is to prepare nano-Fe 3 O 4 first by thermal decomposition method and sequentially load them on α-Al 2 O 3 by impregnation. TEM and XRD results manifested that the controllable, uniform Fe 3 O 4 nanoparticles are monodispersed on the surface of α-Al 2 O 3 . H 2 -TPR demonstrated that the reduction of Fe species was facilitated because of the weak interaction between Fe species and the support. These superior properties contribute to an enhanced catalytic activity and stability compared with the catalyst prepared by directly impregnating ammonium iron citrate on α-Al 2 O 3 . Then, the effect of promoters was investigated at the same Fe loading and nanoparticle size. The appropriate addition of K could enhance the catalytic activity and suppress the secondary hydrogenation. On the contrary, S has a negative impact on CO conversion and strongly decreases C 5+ selectivity. Particularly, the combination of K and S could obtain more pronounced CO conversion and higher lower olefins selectivity (≈40 %). Furthermore, size effects were explored by precisely tailoring the iron oxide particle size with the Fe loading kept constant. It was found that 12.0 nm nano-Fe 3 O 4 on α-Al 2 O 3 with or without K plus S promoters showed the best catalytic activity among the catalysts with different particle size.
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CHEMICAL ENGINEERING JOURNAL
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2016
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IF 5.31
Zhouzhou Feng,Jiajie Yu,Jinming Kong,Tianhe Wang
In this paper, a photocatalytic system for effectively degrading azo dyes is described. The nanostructured porous Al 2 O 3 layer on glass substrate (PAOG)/silver nanoparticles (AgNPs)–Hemin composites were synthesized via photochemical reduction of Ag, self-assembly of 11-mercaptoundecanoic acid (MUA) on AgNPs and subsequently linking Hemin to MUA via coordination bond. PAOG as a nanoporous template was chemically durable, highly porous and allowed chemicals conveniently immobilized on the glass surface. PAOG had a BET surface area of 151 m 2 /g which facilitated the immobilization of AgNPs. The composite was characterized by BET surface area measurements, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared (FTIR) spectrometer and X-ray photoelectron spectroscopy (XPS). The photoreaction degradation processes were examined by UV/vis spectroscopy. Methyl orange (MO) and Acid red 18 solutions were used to evaluate the photocatalytic performance of PAOG/AgNPs–Hemin composite under visible light and UV irradiation. Compared with PAOG/Hemin, the PAOG/AgNPs–Hemin composite had enhanced photocatalytic efficiency due to higher electron transfer efficiency from AgNPs to Hemin. This novel composite with enhanced broad spectrum photocatalytic properties has promising potentials in degradation of dyes by UV and visible light utilization.
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CHEMOSPHERE
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2017
·
IF 4.208
Hongyun Hu,Dunkui Chen,Huan Liu,Yuhan Yang,Hexun Cai,Junhao Shen,Hong Yao
Arsenic emission from fuel combustion and metal smelting flue gas causes serious pollution. Addition of sorbents is a promising way for the arsenic capture from high temperature flue gas. However, it is difficult to remove arsenic from SO 2 /HCl-rich flue gas due to the competitive reaction of the sorbents with arsenic and these acid gases. To solve this problem, arsenic adsorption over γ-Al 2 O 3 was studied in this work to evaluate its adsorption mechanism, resistance to acid gases as well as regeneration behavior. The results show that γ-Al 2 O 3 had good resistance to acid gases and the arsenic adsorption by γ-Al 2 O 3 could be effectively carried out at a wide temperature range between 573 and 1023 K. Nevertheless, adsorption at higher-temperature (like 1173 K) leaded to the decrease of surface area and the rearrangement of crystal structure of γ-Al 2 O 3 , reducing the active sites for arsenic adsorption. The adsorption of arsenic was confirmed to occur at different active sites in γ-Al 2 O 3 by forming various adsorbed species. Increasing temperature facilitated arsenic transformation into more stable chemisorbed As 3+ and As 5+ which were difficult to remove through thermal treatment regeneration. Fortunately, the regeneration of spent γ-Al 2 O 3 could be well performed using NaOH solution.
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PubMed
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Journal of the Iranian Chemical Society
·
2016
·Vol. 14
·期 1
·111-119
·
IF 1.3
Yang Xiaomei,Fu Xiaomin,Bu Ningning,Han Li,Wang Jianfeng,Song Chengying,Su Yunlai,Zhou Lipeng,Lu Tianliang
Cu–Ni/γ-Al 2 O 3 bimetallic catalysts were developed for anaerobic dehydrogenation of non-activated primary aliphatic alcohols to aldehydes. Systematic investigation about the promotion effect of nickel on the catalytic performance was carried out. Hydrogenation of C=C bond rather than C=O bond, was significantly improved over Cu–Ni/γ-Al 2 O 3 catalyst by introducing nickel, which interprets the good conversion of primary aliphatic alcohols. This work would contribute to design new catalysts for dehydrogenation of primary aliphatic alcohols.
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ACS Catalysis
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2016
·
IF 9.307
Jie Sun,Qiuxia Cai,Yan Wan,Shaolong Wan,Li Wang,Jingdong Lin,Donghai Mei,Yong Wang
The promotional effects of a cesium promoter on higher alcohol (C2+OH) synthesis from syngas over Cs2O-Cu/ZnO/Al2O3 catalysts were investigated using a combined experimental and density functional theory (DFT) calculation method. In the presence of a cesium promoter, the C2+OH productivity increases from 77.1 to 157.3 g kgcat–1 h–1 at 583 K due to the enhancement of the initial C–C bond formation. A detailed analysis of chain growth probabilities (CGPs) confirms that initial C–C bond formation is the rate-determining step in the temperature range of 543–583 K. Addition of a cesium promoter significantly increases the productivities of 2-methyl-1-propanol, while the CGP values (C3* to 2-methyl-C3*) are almost unaffected. With the assistance of a cesium promoter, the CGPs of the initial C–C bond formation step (C1* to C2*) increase from 0.13 to 0.25 at 583 K. DFT calculations indicate that the initial C–C bond formation during syngas synthesis over the ZnCu(211) model surface is mainly due to the HCO + HCO coupling. In the presence of Cs2O, the stabilities of key intermediates such as HCO and H2CO are enhanced, which facilitates both HCO + HCO and HCO + H2CO coupling steps with lower activation barriers. In addition, Bader charge analysis suggests that the presence of cesium ions could facilitate nucleophilic coupling between HCO and H2CO for the initial C–C bond formation.
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Journal of Environmental Chemical Engineering
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2016
·
IF 0
Ye Wang,Wenzhong Yang,Xiaoshuang Yin,Ying Liu
Comparative ozonation experiments were carried out to investigate the catalytic ability and mechanism of γ-Al 2 O 3 supported manganese oxide (Mn/γ-Al 2 O 3 ) for the degradation of phenol in aqueous solution. The results showed that 4% Mn/γ-Al 2 O 3 possessed highest catalytic efficiency for the ozonation of phenol than that of other catalysts. The influences of manganese content and catalyst dosage verified that surface hydroxyl groups affected by the solution pH and the point of zero charge (pH PZC ) of catalysts. The Mn/γ-Al 2 O 3 exerted the strongest catalytic activity at initial solution pH of 3.45. The strong interaction between ozone and Mn/γ-Al 2 O 3 was observed and confirmed as a critical step for the catalysis reaction. The surface hydroxyl groups and chemisorbed water acted as the active sites in promoting hydroxyl radicals, while Brönsted acid sites were confirmed as reactive centres for catalytic ozonation in the aqueous phase. The influence of tert -butanol showed that hydroxyl radicals and active oxygen species were involved in the catalytic ozonation of phenol. According to the X-ray photoelectron spectroscopy (XPS) results, the enhancement of electron transfer on the surface manganese oxides were responsible for the catalysis and promoting the formation of active oxygen species. A possible catalytic ozonation mechanism of phenol over Mn/γ-Al 2 O 3 was proposed.
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CERAMICS INTERNATIONAL
·
2017
·
IF 2.986
Huimin Li,Yanfei Chen,Panding Wang,Baosheng Xu,Yongbin Ma,Weibin Wen,Yazheng Yang,Daining Fang
To improve the thermal insulation and mechanical properties of lightweight carbon- bonded carbon fiber composites (CBCF), a porous CBCF decorated with nano SiO 2 -Al 2 O 3 aerogel was prepared by sol-gel impregnation. Results showed that the nano aerogel were uniformly assembled within the pores in the CBCF framework. The aerogel played a significant role on reducing the thermal conductivity of CBCF, which could be mainly ascribed to reduced radiation and gas thermal conductivity of CBCF. Moreover, the aerogel in the CBCF pores hindered the bending fracture or elastic bending/rotation of the fibers and enhanced the mechanical properties of the composites.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2025
·
IF 21.1
Tao Xu,Meihui Jiang,Xuhui Mao,Falak Sher,Tianlin Ren,Kun Xin,Irshad Hussain,Helin Hua,Xu Wang
This study investigated the important role of hydroxyl groups for the preparation of γ-Al 2 O 3 sphere supported metal catalysts. γ-Al 2 O 3 spheres were calcinated at varied temperatures for the analysis of surface hydroxyl group, and they were subsequently loaded with iron to evaluate the metal dispersion and the performance for catalytic ozonation. The results showed that the critical site for metal anchoring was hydroxyl group, thus a higher hydroxyl group content favored the metal dispersion on γ-Al 2 O 3 spheres; meanwhile, the iron-loaded catalysts prepared by the γ-Al 2 O 3 support calcinated at 300 °C achieved the highest catalytic efficiency for p -nitrophenol degradation (74.6 %). The favorable performance of the catalyst was attributed to the excellent dispersion of iron oxide particles, and the abundant oxygen vacancy sites that facilitated the formation of ozone-activating sites, Fe-centered hydroxyl groups ([Fe-OH]). This study provides an important theoretical guidance for the design and application of ozone catalysts.
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