ChemCatChem
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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.
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高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2017
·
IF 3.454
Fei Zuo,Fan Meng,Dong-Tao Lin,Jun-Jie Yu,Hong-Jian Wang,Shen Xu,Wei-Ming Guo,Carmen Cerecedo,Víctor Valcárcel,Hua-Tay Lin
A novel composite of 12 mol% CeO 2 -stablized tetragonal ZrO 2 reinforced with Al 2 O 3 whiskers (designated as Ce-TZP/A w ) has been prepared and studied in this work. The objective of this investigation was to systematically study the influence of whisker-aspect-ratio on the densification behaviors, microstructure evolution, and mechanical properties of Ce-TZP/A w composite. Results showed that the sintered density of composite increased and the grain growth tended to diminish with the decrease in whisker aspect radio. Both the fracture toughness and flexural strength reached maximum values of 475 ± 12 MPa and 11.4 ± 0.2 MPa m 1/2 , respectively at a whisker aspect ratio of about 12. It was also observed that the fracture toughness, flexural strength and tetragonal to monoclinic ZrO 2 transformation of the dual-phase composite exhibited similar variation trend as a function of the whisker-aspect-ratio, which suggested that the stress-induced phase transformation should be the main toughening and strengthening mechanism in the Ce-TZP/A w composite.
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高影响因子
Nanoscale
·
2025
·
IF 5.1
Jiasheng Wang,Tianyu Zhang,Jiliang Song,Fengxin Zhang,Hong Liu,Wan-Hui Wang,Ming Bao
Unsaturated alcohols (UOLs) are important fine chemical intermediates. Thus, it is of great significance to design and prepare catalysts for highly selective hydrogenation of CO of α,β-unsaturated aldehydes (UALs). In this paper, a fluffy mesoporous Al2O3-supported Ag–In2O3 catalyst (Ag-In2O3/f-m-Al2O3) was synthesized by employing a two-solvent method, in which Ag and In2O3 form a Mott–Schottky junction and lead to electron transfer from In2O3 to Ag. Electron-rich Ag repels the CC bond owing to “four-electron repulsion”, and electron-deficient In2O3 acts as the electrophilic site to adsorb the O atom of the CO bond, thus improving the selectivity towards UOLs. In addition to a larger specific surface area and smaller mass transfer resistance, the fluffy mesopore Al2O3 exhibits a large number of Lewis acid sites, which can further improve UOL selectivity. With the help of Ag–In2O3/f-m-Al2O3, high UOL selectivity can be obtained from UALs containing aliphatic, aromatic and heterocyclic groups. This elaborate design of the catalyst could contribute to the highly selective hydrogenation of UALs to UOLs.
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PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Shu-Xiang Xiang,Jin-Peng Wang,Su Gao,Zhan-Kuo Guo,Hui-Lin Jiang,Bao-Xia Dong,Yun-Lei Teng
The CH 4 yield over dual functional materials (DFMs) remains low and requires further improvement. In this work, we first examined the influence of Mn on the performance of the Ni-CaO/γ-Al 2 O 3 DFM for CO 2 capture and in situ methanation. Our results showed that the MnNi-DFM-3 (MnNi-CaO/γ-Al 2 O 3 DFM) exhibited the best performance at 350 °C, with a CH 4 yield of 0.56 mmol/g which is 4 times higher than that of the Ni-DFM-1 (Ni-CaO/γ-Al 2 O 3 DFM) (0.14 mmol/g). Nanoscale characterization revealed that highly scattered Mn 3 O 4 acted as a barrier preventing the agglomeration of Ni-based catalysts. Furthermore, our density functional theory (DFT) analysis demonstrated that the introduction of Mn enhanced the activation of CO 2 , promoted the dissociation of H 2 and intermediates, and reduced the activation energy needed to produce carboxylic acid intermediates on the Ni catalyst. The prepared MnNi-DFM is promising to be a cheap efficient material for CO 2 capture and in situ methanation. This work opens up a new pathway for enhancing the performance of DFMs using inexpensive transition metals.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Ke Lu,Yihao Xu,Hao Yuan,Jianping Liang,Hongli Wang,Jie Zhang,Yinong Li,Dezheng Yang
The design of efficient reaction units and the use of efficient catalysts for green and non-polluting ammonia synthesis is an important and challenging issue. In this paper, we design a high-efficiency reaction device, a coaxial double dielectric barrier discharge plasma reactor, which produces a more uniform plasma discharge during operation, changes the discharge characteristics, promotes the physicochemical reactions of ammonia synthesis, improves the efficiency of ammonia production, and reduces the energy consumption. The use of transition metal Ni and its metal oxide NiO loaded on the carrier as catalysts. The catalyst was comprehensively characterized by X-ray photoelectron spectroscopy, X-ray diffraction, and scanning electron microscope. The reaction mechanism of plasma-catalyzed ammonia synthesis was studied in detail by combining discharge characteristics, optical emission spectroscopy, and catalyst characterization. The reaction conditions and discharge parameters of the dielectric barrier discharge plasma reactor were optimized, which greatly improved the energy efficiency and synthesis rate, which could reach 1002 μmol g −1 h −1 under the optimal conditions. Based on the experimental results, we analyzed how different conditions and parameters affect the reaction of ammonia synthesis.
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高影响因子
FUEL PROCESSING TECHNOLOGY
·
2018
·
IF 3.956
Limo He,Song Hu,Long Jiang,Guang Liao,Xiaofang Chen,Hengda Han,Lingfeng Xiao,Qiangqiang Ren,Yi Wang,Sheng Su,Jun Xiang
The effects of catalyst supports (γ-Al 2 O 3 and α-Al 2 O 3 ) on hydrogen yield and carbon nanotubes formation were studied during steam reforming of toluene over Ni-based catalysts. Hydrogen yield and CNTs quality over Ni/γ-Al 2 O 3 were better than those over Ni/α-Al 2 O 3 at S/C ratio of 1 due to the high Ni dispersion of Ni/γ-Al 2 O 3 . With the increasing of steam addition, CNTs production remarkably increased over Ni/α-Al 2 O 3 , while it decreased over Ni/γ-Al 2 O 3 . The CNTs on Ni/γ-Al 2 O 3 were corroded at S/C ratio of 3 by excess steam. Toluene conversion and hydrogen yield over Ni/α-Al 2 O 3 were significantly larger than those over Ni/γ-Al 2 O 3 , which was attributed to the different effects of CNTs on catalytic activity . The strong interaction between Ni particle and γ-Al 2 O 3 led to the base-growth mechanism of CNTs on Ni/γ-Al 2 O 3 in which Ni particles located at the bottom of CNTs, thus the growth of CNTs covered Ni active sites and decreased catalytic activity of Ni/γ-Al 2 O 3 . By contrast, owing to weak interaction, CNTs grown on Ni/α-Al 2 O 3 followed tip-growth mechanism that would increase Ni dispersion and promote reforming reaction .
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高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Zhuoqing An,Yuan Gao,Jiajing Chen
The CaO-MgO-Al 2 O 3 -SiO 2 (CMAS) glass-ceramics containing complex nucleation agents including La 2 O 3 and Fe 2 O 3 were prepared by melt process. The effects of these complex nucleation agents on the crystallization and microstructure of CMAS glass-ceramics were investigated through the thermal analysis (DSC), X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM) and Raman spectroscopy. The results indicated that the addition of La 2 O 3 and Fe 2 O 3 decreases viscosity and ion movement resistance. Furthermore, the La 2 O 3 can increase the crystallization peak temperature, while the Fe 2 O 3 has an inverse effect. The crystallization activation energy decreased from 298.87 to 264.26 kJ/mol as the mole ratio of La 2 O 3 increased to 2%. Conversely, when the mole ratio of Fe 2 O 3 increased to 2%, the crystallization activation energy increased from 298.87 to 347.21 kJ/mol. However, the addition of La 2 O 3 and Fe 2 O 3 decreased the Avrami parameter and promoted the surface crystallization within the CMAS glass system, as confirmed by the microstructure analysis. The crystal show branch-like crystal morphology when La 2 O 3 adding, whereas Fe 2 O 3 addition led to a compact, seaweed-like morphology with a fractal structure. With decreasing La 2 O 3 and increasing Fe 2 O 3 , the width of the dendritic branches increased. The major crystal phases detected on the surface were augite and diopside phase. Fe is predominantly present in the augite phase and La is primarily incorporated as a solid solution within the crystal phase.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Xiaoxia Zhang,Zhipeng Zhou,Junjie Liao,Liping Chang,Jiancheng Wang,Weiren Bao
The ultra-deep removal of thiophene from coke oven gas (COG) is critical for the conversion of COG to methane. Currently, Cu/ZnO/Al 2 O 3 is considered as a promising sorbent for thiophene removal; however, its desulfurization performance is currently unable to meet the requirements for industrial applications. Here, a zirconium modification strategy is proposed to overcome this problem, allowing zirconium loaded copper-based sorbents (Cu/ZnO/Al 2 O 3 /ZrO 2 ) with significantly improved thiophene removal performance and high activity to be obtained. Characterization results showed that zirconium improved both the dispersion of copper and the concentration of Lewis acid sites on the sorbent surface. A ZrO 2 concentration of 2 % resulted in stronger Cu-Zn interaction, and the dispersion of Cu on the surface of the sorbent reached its maximum value (49.20 %). Additionally, the Lewis acid strength was also maximized, which greatly improved the desulfurization activity and resulted in a breakthrough adsorption capacity of thiophene (Q b-thiophene ) of 36.24 mg/g, which was about 17 % higher than that of the unmodified Cu/ZnO/Al 2 O 3 sorbent. These results demonstrate that the sulfur capacity of the sorbent can be increased by increasing the number of acidic sites on its surface, paving the way for ultra-deep thiophene removal in industrial applications.
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高影响因子
ACS Catalysis
·
2024
·
IF 11.3
Yanmei Cai,Cunbiao Lin,Xingwen Cha,Yiling Wu,Xiaoping Rao,Kok Bing Tan,Dongren Cai,Gui-Lin Zhuang,Guowu Zhan
The supported Ni/In2O3 catalysts are of great interest in CO2 hydrogenation, but the formation of the In0 or Ni–In alloy phases due to over-reduction would lead to rapid catalyst deactivation. Herein, thin Al2O3 films were deposited on the Ni/In2O3 surface by atomic layer deposition (ALD) as an antireduction agent, which enables the In2O3 catalyst to maintain a significant abundance of active In3+ species even during high-temperature H2 treatment (400 °C, 2 h), thereby effectively resisting the deactivation caused by over-reduction of In2O3. Various characterization methods confirm the antiover-reduction effect of ALD-Al2O3 films, namely, inhibiting the formation of In0 and In3Ni2 alloys during high-temperature H2 treatment and facilitating the reoxidation of low-valence In to form the active In2O3–x phase in the presence of a CO2 atmosphere. As treated with H2 at 400 °C, the 5Al2O3/Ni/In2O3-R400 catalyst exhibited an STYMeOH of 7.39 gMeOH h–1gNi–1 and a methanol selectivity of 64% (reaction conditions: 3 MPa, 300 °C, and 12,000 mL gcat–1h–1). Particularly, the STYMeOH increased by 11.5 times as compared with that of the Ni/In2O3-R400 catalyst without coating the ALD-Al2O3 layer (0.59 gMeOH h–1gNi–1). Density functional theory (DFT) calculations validate the effectiveness of specific charge transfer tendencies in suppressing the over-reduction of high-valence In species. Through the analysis of the crystal orbital Hamilton population (COHP) and projected density of states (PDOS) electronic structures of the adsorbate species, the Al2O3/Ni/In2O3 catalyst is shown to significantly enhance CO2 activation and further catalytic reactions. Accordingly, this study unveils the deactivation mechanism of In2O3-based catalysts due to over-reduction and provides a method to regulate their reduction level by depositing ALD-Al2O3 films on the In2O3-based catalysts.
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高影响因子
Case Studies in Thermal Engineering
·
2024
·
IF 6.4
Lirong Li,Zhiping Xiao,Sihan Liu,Chengwei Xu
Methanol-based physical absorption, known for its effective CO 2 capture ability, has been employed in acid gas removal (AGR) unit. However, the high energy consumption associated cooling methanol and acid gas hampers its widespread adoption. To address this challenge, numerous studies have explored the use of nanoparticles to enhance the CO 2 absorption at room temperature, thereby reducing the energy requirements. In this study, the objective is to synthesize and characterize the Al 2 O 3 -methanol nanofluid and investigate its application in a bubble column for improved mass transfer rates during CO 2 absorption. The methanol based Al 2 O 3 nanofluid was prepared using the two-step method with ultrasonication technology and CO 2 absorption in the resultant product was investigated. Initially, 0.001 vol%, 0.01 vol % and 0.1 vol% Al 2 O 3 nanoparticles was added to methanol solution and to mixture them well via ultrasonication technology. The static settlement method and zeta potential analysis were utilized to characterize the stability of the as-prepared nanofluid. Both impact of sonication power and time on the stability of nanofluid were discussed as well. Then, numerical simulations was employed to investigate the mass transfer coefficient for CO 2 absorption and the numerical uncertainty was carefully analyzed to verify the reliability of the numerical method. It revealed a 7.3%, 29.2% and 60.7% enhancement in mass transfer coefficient during CO 2 absorption for 0.001 vol%, 0.01 vol% and 0.1 vol% nanoparticles under room temperature, respectively. The visualized reason for this improvement was related to the enhanced bubble breakup and coalescence after adding nanoparticles to methanol. The expanded interfacial area between gas and liquid plays a vital role in the mechanism of this improvement.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 42
·e56094
·
IF 2.7
Zhiting Tu,Weijian Wu,Zhifeng Hao,Xiang Chen,Qiuling Chen,Xiaonan Huang,Mohamed S. Selim,Jian Yu
In order to overcome the commercialized silicone-based thermal interface materials' issues such as oil leakage and mechanical damage, we developed a thermoset silicone rubber matrix (SR) achieved through the condensation reaction of hydroxyl silicone oil and tetraethyl silicate. Additionally, we constructed a self-healing and recyclable silicone rubber matrix (SCNR) by incorporating heat reversible ionic and hydrogen bonds between carboxyl and amino functionalized polydimethylsiloxane. Finally, the flexible, low oil leakage, self-healing, and recyclable composites Al 2 O 3 /BN@SR/SCNR was prepared by adjusting the ratio of SR/SCNR and the spherical alumina and boron nitride (BN) fillers. The results indicated that with SR/SCNR mass ratio of 1/0.075 and filler content of 70 wt%, the thermal conductivity of the composite reaches 1.866 W m −1 K −1 , 646% increasing over the SR/SCNR matrix. The self-healing efficiency reaches 97% and the thermal conductivity remains essentially unchanged after being recycled for three times. The composites can be bent and twisted multiple times and still return to their original shape. Notably, the oil leakage of the Al 2 O 3 /BN@SR/SCNR composites is significantly lower than that of additive silicone composites. Therefore, the recyclable thermal conductivity composite developed in this study provides a promising solution for improving the durability of heat dissipation materials in electronic devices.
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CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Jianfeng Huang,Haowen Fan,Xuetao Shen,Xinzi Zhong,Liyun Cao,Meng Yuan,Hang Yan,Tian Ji,Mingxin Liu,Yong Zhao,Yijun Liu
To improve the oxidation resistance of carbon/carbon (C/C) composites at intermediate temperatures, we present a novel design concept for an antioxidative coating that incorporates ceramic microcapsules engineered for self-healing and in situ toughening. These microcapsules, featuring a SiB 6 @Al 2 O 3 core-shell structure, were synthesized via a sol-gel process and embedded into a SiB 6 @Al 2 O 3 -SiC-C/C composite through dip-coating. Upon crack formation, the microcapsules rupture, releasing a healing agent that facilitates crack closure. Concurrently, the oxidation product SiO 2 from the core reacts with Al 2 O 3 , forming mullite whiskers at the damage site, thereby enhancing toughness. This combined self-healing and toughening mechanism significantly enhances the antioxidative performance of the coating. After 540 hours of exposure to an oxidizing environment at 1573 K, the coating demonstrated minimal oxidation, with a weight loss of just 0.27% and a specific weight loss of 6.80×10 -4 g/cm 2 .
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