APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Zulfiqar Ali,Yang-wen Wu,Yue Wu,Zulqarnain Arain,Ming-xin Xu,Qiang Lu,Heping Ma,Huan-yu Zhao
Lead (Pb) species are inescapable constituents of the flue gas from coal-fired power plants and other thermal devices, which can cause impeding effects on the selective catalytic reduction (SCR) reactions. Here, the poisoning effects of Pb on the V 2 O 5 -MoO 3 /TiO 2 type SCR catalyst were examined. The poisoned catalysts were prepared by the solid diffusion and incipient wetness impregnation (IWI) methods. The catalytic activity tests indicated that the Pb-doped catalyst prepared by the IWI method suffered a considerable drop in catalytic activity, while a slender influence was observed on the Pb-loaded catalysts prepared by solid diffusion method. Comprehensive characterizations and density functional theory (DFT) calculations were performed on the fresh and poisoned catalysts prepared by the IWI method to unveil the deactivation mechanism. The results showed that Pb species covered the active sites (V species) on the catalyst surface, resulted in the decrease in chemisorbed oxygen, hence reducing the surface acidities. The decrease in reducibility of the catalyst was an important factor for poisoning of the catalyst. Moreover, Pb species reacted with MoO 3 to form PbMoO 4 which agglomerated on the catalyst surface to further deactivate the catalyst.
研究领域:
环境科学
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催化化学
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产品关联
DOI
高影响因子
Royal Society Open Science
·
2018
·Vol. 5
·期 11
·
IF 2.504
Chao Chen,Lei Cai,Xinchen Shangguan,Liang Li,Yanping Hong,Guoqiang Wu
Developing high-efficiency hetero-catalysts for transesterification reaction is of great importance in the production of biodiesel from Jatropha curcas L. seed oil (JO). Here, we synthesized a series of sulfated TiO2 by treating with varying H2SO4 concentration (SO42−/TiO2) and TiO2 catalysts and applied to the transesterification of JO. Furthermore, these heterostructures were characterized by many characterization methods including XRD, FT-IR, N2-adsorption, SEM, TEM, TG, py-IR and NH3-TPD, and their catalytic performance was investigated under various operating conditions. The results reveal that both the Brønsted and Lewis acid sites are presented in the SO42−/TiO2 catalysts, while only Lewis-type sites are observed in the TiO2 catalyst. And the acid intensity, surface area and mesoporous volume of catalysts are improved obviously after treating TiO2 with sulfuric acid. Then the SO42−/TiO2 catalysts exhibit much higher catalytic activity than TiO2 catalyst, which is attributed to the larger surface area and mesoporous volume and stronger acidity. Furthermore, the reusability behaviour of 1.5 SO42−/TiO2 catalyst in the transesterification of JO was also studied.
研究领域:
催化化学
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可再生能源
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纳米材料
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产品关联
DOI
PubMed
高影响因子
ChemCatChem
·
2022
·Vol. 14
·期 10
·e202200001
·
IF 5.497
Helong Sun,Lufa Hu,Zhangyang Li,Junyu Lang,Chunling Wang,Xiaohao Liu,Yun Hang Hu,Fangming Jin
Graphical POMs : SiW 12 O x /TiO 2 was demonstrated as an ultra-stable heterogeneous catalyst with tailored molecular interfacial structure and super acidity for photocatalytic oxidation of methane to formic acid. This fabrication method could be relevant for other type POMs based photocatalyst, which provide a way to fabricate ultra-stable molecular interface photo-catalyst with highly efficiency. The interface and surface acidity of heterogeneous catalysts are widely applied to manipulate the catalytic performance. However, the interface structure prepared by traditional synthesis processes required multistep procedures, which was still lack of controllability and stability. Here, we show a general synthetic approach to fabricate ultra-stable heterogeneous catalysts with tailored molecular interfacial structure and super acidity in one step. The as-synthesized SiW 12 O x /TiO 2 catalyst was used for photo-catalytic conversion of methane to value-added oxygenates. We propose that the formed molecular interface W 12 −OH−Ti coupled with the introduced Brønsted acid sites of POMs, results in enhancing the photocatalytic performance. Namely, the addition of SiW 12 O x can reduce the recombination of electrons and holes for triggering charge separation owing to the photoelectron capturing by proton, improving electron transfer to reactants and thereby promoting catalytic activity. This fabrication method provides a way to build molecular interface photo-catalyst by POMs with super acidity and ultra-stable structure.
研究领域:
催化化学
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材料科学
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环境科学
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产品关联
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Chong Xia,Yuanqing Zhu,Song Zhou,Yongming Feng,Jie Shi
Besides catalyzing NOx reduction, the V 2 O 5 -WO 3 /TiO 2 catalyst can effectively suppress the formation of urea (CH 4 N 2 O) decomposition by-products in selective catalytic reduction (SCR). However, current research lacks a clear understanding of the impact of urea and its by-products on the catalyst' performance. Additionally, there is no available kinetic model to describe the decomposition process of urea and its by-products on the V 2 O 5 -WO 3 /TiO 2 catalyst. In this paper, the decomposition process of urea and its by-products on the catalyst was firstly investigated via thermogravimetric analysis (TGA). It was found that increasing the catalyst dosage can accelerate urea decomposition and block the transformation pathways from urea and biuret (C 2 H 5 N 3 O 2 ) to cyanuric acid (cya, C 3 H 3 N 3 O 3 ). However, as the decomposition temperature of the by-products increased, a larger amount of catalyst was also required. Secondly, the impact of urea and its by-products on the NOx reduction performance was investigated via the SCR test bench. The results showed that, at 200 ℃, the addition of 20 % urea, biuret, or cya decreased the NOx reduction rate by 7.2 %, 9.8 %, and 11.0 % respectively. Furthermore, the catalyst's performance was significantly improved at 400 ℃ dues to the decomposition of urea and its by-products. Then, various characterization techniques were used to analyze the morphology and chemical composition of the urea decomposition products on the catalyst at different temperatures. On this basis, a simplified urea non-catalytic and catalytic coupling mechanism model was developed, which included 7 species and 16 reactions. Finally, the kinetic parameters of the proposed urea catalytic decomposition model were optimized utilizing TGA test data, density functional theory (DFT), and genetic algorithms (GA). This study can provide guidance for the elimination of SCR urea deposits in engineering applications.
研究领域:
环境科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL PHYSICS LETTERS
·
2019
·
IF 1.901
Yiqing Zeng,Yanan Wang,Yahan Meng,Fujiao Song,Shule Zhang,Qin Zhong
Herein, we compared the catalyst formation process of three Pt/TiO 2 catalysts prepared by impregnation (PtTi–I), deposition precipitation (PtTi–D) and photo-deposition (PtTi–P) to investigate its effect on oxgyen activation and toluene oxidation activity. The encapsulation of TiO 2 on Pt particles induced by high temperature strengthened the metal–support interaction (MSI) but inhibited the activation of oxygen over PtTi–I catalyst, thus it showed the poorest activity in toluene oxidation. Since the selective deposition of Pt on certain face of TiO 2 during photo-deposition process, PtTi–P exhibited stronger MSI and higher activity although it possessed much larger Pt particles than PtTi–D.
研究领域:
催化化学
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环境科学
✓ 已验证
DOI
高影响因子
Chemistry-An Asian Journal
·
2021
·Vol. 16
·期 18
·2633-2640
·
IF 4.568
Guanghao Qiu,Qijun Pei,Yang Yu,Zijun Jing,Jintao Wang,Teng He,Ping Chen
Graphical A strategy for regulating strong metal-support interaction (SMSI) was proposed. The alkaline earth metal salts were doped into a Ru/TiO 2 catalyst, which successfully prevented the migration of TiO 2-x overlayer to Ru nanoparticles via in situ formation of titanates, while the electrons transfer from support to metal nanoparticles was strengthened. The alkaline earth metal salts-doped Ru/TiO 2 catalysts exhibited superior activity in the catalytic hydrogenation of aromatics. Classical strong metal-support interaction (SMSI) is of significant importance to heterogeneous catalysis, where electronic promotion and encapsulation of noble metal by reducible support are two main intrinsic properties of SMSI. However, the excessive encapsulation will inevitably hamper the contact between active sites and reactant, leading to reduced activity in catalysis. Herein, alkaline earth metal salts are employed to depress the encapsulation of Ru nanoparticles in Ru/TiO 2 catalyst in the present study. Thermodynamic calculation, transmission electron microscopy (TEM) and chemisorption results show that the alkaline earth metal salts could successfully prevent the migration of TiO 2-x overlayer to Ru nanoparticles in Ru/TiO 2 catalyst via in situ formation of titanates, resulting in high exposure of active metal. Meanwhile, X-ray photoelectron spectroscopy (XPS) and hydrogen temperature-programmed reduction (H 2 -TPR) results reveal that an even stronger electron donation from the reduced support to Ru nanoparticles is achieved. As a result, the alkaline earth metal salts-doped Ru/TiO 2 catalysts exhibit superior activity in catalytic hydrogenation of aromatics, which is in contrast to the pristine Ru/TiO 2 catalyst that shows negligible activity under the same conditions due to the excess encapsulation of Ru nanoparticles in Ru/TiO 2 catalyst.
研究领域:
催化化学
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材料科学
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
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IF 8.1
Bowen Li,Zhen Zhang,Tingfeng Shan,Qi Zhang,Yusi He,Xiangfu Wang,Hongmin Yang
The by-product SO 3 , generated by the conventional catalyst V 2 O 5 -WO 3 /TiO 2 employed in selective catalytic reduction (SCR) systems, has garnered attention in pollution control efforts. Studies on existing control have predominantly concentrated on the tail gas section, with insufficient understanding of in-situ suppression theories and methods at the source of SO 3 generation. We propose for the first time the introduction of low-valence reduced sulfur to synthesize a novel SCR catalyst, V 2 O 5 -WS 2 /TiO 2 , which elucidates the remarkable effect and in-situ mechanism of action in inhibiting SO 3 formation at its source. Compared to conventional catalysts, the new catalysts showed enhanced SO 3 inhibition, particularly at 350 °C, where SO 3 production was 64.1 % and 33.9 % lower than that with VTi and VW/Ti catalysts, respectively. This was due to their reduced surface area, smaller pore volume, and fewer alkaline sites, which hindered SO 2 adsorption and oxidation. The results revealed that S 2− on the catalyst surface reacts with V 5+ , reducing it to V 4+ and V 3+ . This reaction hinders the interaction between V 5+ -OH and adsorbed SO 2 , thereby reducing the formation of VOSO 4 intermediates. Furthermore, the W S bond in WS 2 impedes the formation of intermediate HSO 4 − , and the reduction of these intermediates ultimately leads to a decrease in SO 3 generation. Additionally, the incompletely depleted S 2− reacts with the final SO 3 produced, forming SO 2 and SO 4 2− , which further decreases the SO 3 generation rate and supports the maintenance of a reduced state on the catalyst surface. It is evident that low-valence reduced sulfur plays a crucial role in inhibiting SO 3 generation.
研究领域:
环境科学
·
催化化学
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产品关联
DOI
高影响因子
Russian Journal of Physical Chemistry B
·
2023
·Vol. 17
·期 3
·695-701
·
IF 1.4
Wang Y.,Dong X.,Jiang B.,Dai X.,Song H.
Abstract An alternative route to synthesize Ni 2 P–N/TiO 2 in N 2 atmosphere instead of H 2 atmosphere by thermal treatment method was proposed, and the Ni 2 P–N/TiO 2 catalyst was investigated in benzofuran hydrodeoxygenation (BF HDO) performance. X-ray diffraction (XRD), transmission electron microscope (TEM), N 2 -adsorption specific surface area measurements, CO uptake and X-ray photoelectron spectroscopy (XPS) were used to characterize the catalysts. The results showed that, the Ni 2 P–N/TiO 2 catalyst possessed a smaller and highly dispersed Ni 2 P particles on the catalysts showed a higher benzofuran hydrodeoxygenation conversion (91.9%) and ethylcyclohexane selectivity (70.4%).
研究领域:
化学工程
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催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale
·
2024
·
IF 5.8
Heyun Lin,Wenzhe Zhang,Huachen Shen,Hailing Yu,Yunlei An,Tiejun Lin,Liangshu Zhong
The catalytic behavior of CO hydrogenation can be modulated by metal–support interactions, while the role of the support remains elusive. Herein, we demonstrate that the presence of strong metal–support interactions (SMSI) depends strongly on the crystal phase of TiO2 (rutile or anatase) and the treatment conditions for the TiO2 support, which could critically control the activity and selectivity of Ru-based nanocatalysts for CO hydrogenation. High CO conversion and olefin selectivity were observed for Ru/rutile-TiO2 (Ru/r-TiO2), while catalysts supported by anatase (a-TiO2) showed almost no activity. Characterization confirmed that the SMSI effect could be neglected for Ru/r-TiO2, while it is dominant on Ru/a-TiO2 after reduction at 300 °C, resulting in the coverage of Ru nanoparticles by TiOx overlayers. Such SMSI could be suppressed by H2 treatment of the a-TiO2 support and the catalytic activity of the as-obtained Ru/a-TiO2(H2) can be greatly elevated from almost inactive to >50% CO conversion with >60% olefin selectivity. Further results indicated that the surface reducibility of the TiO2 support determines the SMSI state and catalytic performance of Ru/TiO2 in the CO hydrogenation reaction. This work offers an effective strategy to design efficient catalysts for the FTO reaction by regulating the crystal phase of the support.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Songshan Zhu,Shimin Ma,Di Song,Yunzhu Wang,Jichang Lu,Tianhao Ai,Huihui Lu,Sufang He,Yongming Luo
The dynamic relationship of TiO 2 crystal phase and strong metal-support interactions (SMSI) of Ni/TiO 2 catalyst was investigated to reveal the induction period of glycerol steam reforming. Comprehensive investigations confirmed that the SMSI between Ni 0 and anatase TiO 2 was formed by anatase TiO 2 encapsulated Ni 0 after H 2 reduction at 500 °C for the Ni/TiO 2 catalyst calcined at 500 °C (Ni/Ti-500R), which inhibited the contact of Ni 0 active sites with reactants and led to the low hydrogen yield in the initial stage of the reaction. Interestingly, the dynamic conversion of anatase to rutile during the GSR process at 600 °C caused the TiO 2 overlayers on the Ni 0 particles to gradually fade, exposing more Ni 0 sites, resulting in a gradual increase in hydrogen yield to 5.93 mol H2 /mol glycerol . In addition, Ni/Ti-500R with a dynamic SMSI inhibited Ni 0 particles sintering and encapsulated carbon deposition, resulting in relatively better stability (21 h) after induction period. In comparison, the designed Ni/TiO 2 catalyst calcined at 600 °C (Ni/Ti-600R) with rutile TiO 2 as the main component inhibited the formation of the classical SMSI, even after 600 °C H 2 reduction, and no excessive TiO 2 encapsulated Ni 0 particles were observed, so no obvious induction period occurred. This study provides new insights into the relationship of SMSI with crystal phases and the induction period in multiphase catalysis, also a new strategy for designing efficient catalysts.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Yunfei Xu,Ying Li,Yongjian Wei,Haiou Liang,Tong Xu,Yinghui Sun,Jie Bai
Photothermal synergistic catalysis of Suzuki-Miyaura coupling reaction not only utilizes the solar energy efficiently, but also reduces the energy consumption. It is a green organic synthesis method for constructing C–C bonds, which has a wide application. In this work, we constructed a PdO/g-C 3 N 4 /TiO 2 bilayer tubular structure material with a heterojunction structure by a simple and effective method. The catalyst exhibited efficient photothermal synergistic catalytic performance in Suzuki coupling reaction under visible light irradiation. The influence of the catalyst’s structure, morphology, composition, and photothermal response on the Suzuki coupling reaction were discussed based on a series of characterizations and activity test of the catalyst. The results showed that the PdO/g-C 3 N 4 /TiO 2 catalyst contained an effective g-C 3 N 4 /TiO 2 heterojunction structure. Under visible illumination, the differences in interfacial charge concentration and electron affinity between these two different types of semiconductors lead to charge rearrangement and transfer, which greatly improves the carrier separation efficiency. Meanwhile, palladium metal exhibits excellent electron deposition effects, both as an active metal center for SMC reactions and as an electron acceptor for facilitating photoelectron transfer. Electron-rich palladium atoms play an important role in C–C bond formation reactions, improving catalytic efficiency. The PdO/g-C 3 N 4 /TiO 2 catalyst has excellent catalytic activity and can catalyze the SMC reaction under visible light and at 0 ℃, the yield reached 85.6%, which is comparable to the activity of thermal catalysis for 15 minutes. Furthermore, after five cycles, the PdO/g-C 3 N 4 /TiO 2 catalyst still maintained an 83.1% yield, demonstrating excellent cycle stability. This article offers an effective strategy for preparing heterojunction catalyst with visible light response for photothermal reaction and presents the potential of these catalysts as a way to improve the efficiency and sustainability of Suzuki coupling reactions.
研究领域:
材料科学
·
催化化学
·
有机合成
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2020
·
IF 7.888
Xiqiang Tian,Muhammad Zahid,Jiang Li,Wang Sun,Xiaoyu Niu,Yujun Zhu
The addition of a suitable co-catalyst is an encouraging way to enhance the catalytic performance of Pd based catalyst with low content. Herein, we describe an easy synthesis of Mo 2 N-TiO 2 with well-dispersed Mo 2 N nanoparticles through one pot evaporation-induced self-assembly and nitridation treatment method. Moreover, a green bio-reductive approach with Catalpa Fruit ( CF ) extract was adopted to fabricate Pd/Mo 2 N-TiO 2 catalysts for promoting selective hydrogenation of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) as model reaction. Among these Pd/Mo 2 N-TiO 2 catalysts, 0.8 wt%Pd/Mo 2 N-TiO 2 exhibits significantly high catalytic activity for selective hydrogenation of various nitrophenols and cinnmaldehyde. Importantly, the catalytic activity of the catalyst prepared by the reduction method of the CF extract is higher than that prepared by the reduction method of NaBH 4 . A serials of characterization, including XRD, N 2 adsorption–desorption, TEM, XPS, CO chemisorption and CO-FTIR etc., was carried out to investigate the influence of the prepared method on the surface Pd species and activity. The high performance can be attributed to the specific nanostructure characteristics of the catalyst and the good synergistic effect between Pd and Mo 2 N, improving the dispersion of Pd nanoparticles atoms and the exposure of more active Pd atoms (surface Pd 0 species) on 0.8 wt%Pd/Mo 2 N-TiO 2 due to the CF extract as reductant.
研究领域:
催化化学
·
环境科学
·
材料科学
✓ 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）