Catalysis Science & Technology
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2020
·Vol. 10
·期 6
·1941-1951
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IF 5.721
Shaohua Chen,Hui Li,Yu Hao,Rui Chen,Tiehong Chen
A series of porous Mn-based oxides (mullite SmMn2O5, perovskite SmMnO3, spinel Mn3O4 and bixbyite Mn2O3) were systematically prepared and applied in ethanol and toluene catalytic oxidation. Among them, SmMn2O5 exhibited the highest catalytic activity, the best hydrothermal stability and the highest durability. Due to the different compositions and structures of the catalysts, the surface composition, Mn-valence state, reduction properties, and adsorption and desorption behavior of oxygen and ethanol were different as characterized by XPS, H2-TPR, O2-TPD and ethanol-TPD measurements. Based on the characterization results, the relationship between the catalyst structure (crystal and electronic structure) and catalytic activity was discussed in terms of their crystal field configurations and structures of the energy bands. The superior activity of SmMn2O5 could be attributed to dz2 orbital occupancy near the Fermi level determined by the Mn3+-centered pyramidal field, as well as the existence of a Mn3+–Mn3+ dimeric structure, which is critical for C–C bond cleavage.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
Catalysts
·
2020
·Vol. 10
·期 2
·143
·
IF 3.52
Chengxiong Wang,Dezhi Ren,Junchen Du,Qinggao Qin,Aimin Zhang,Li Chen,Hao Cui,Jialin Chen,Yunkun Zhao
Ceria-modified Pt/Al2O3catalyst has been commonly prepared by the impregnation of platinum on ceria-modified alumina and widely applied in the chemical industry and automotive industry. The in situ diffuse reflectance infrared Fourier transformed spectroscopy (DRIFTS), and thermogravimetric (TG) analysis techniques were employed to investigate the typical mechanisms of the bis(ethanolammonium)hexahydroxyplatinate(IV) and cerium nitrate decomposition catalyzed by Ptδ+species for the facile synthesis of CeO2-Pt/Al2O3catalyst. It was found that Pt4+-catalyzed decomposition of cerium nitrate leads to the higher dispersity of ceria and forming more active oxygen species, on the basis of X-ray diffraction (XRD) and H2temperature-programmed reduction (H2-TPR) results. The in situ activity measurements were also performed to investigate the reaction mechanisms and the specific activities for the catalytic CO, NO, C3H6and C3H8co-oxidation. The results indicate that undesirable N2O by-product is formed by the selective catalytic reduction (SCR) of NO by C3H6below 350 °C. The cerium addition effectively improves the activity of catalytic oxidation, but exhibits an increased N2O yield, due to the increased reducibility.Keywords:platinum;ceria;in situ characterization;catalytic oxidation
研究领域:
化学工程
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材料科学
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DOI
高影响因子
Catalysis Science & Technology
·
2016
·Vol. 6
·期 12
·4337-4344
·
IF 5.287
Xiaolong Liu,Junlin Zeng,Jian Wang,Wenbo Shi,Tingyu Zhu
Ruthenium-based catalysts Ru/TiO2, Ru/SiO2, Ru/γ-Al2O3, and Ru/ZrO2 were prepared and evaluated for CH3Br oxidation, and Ru/TiO2 showed better catalytic performance than the other samples. The product yields and selectivities were also studied. The thermal stability was examined with a 48 h on-stream test. The influence of water vapor on the catalytic oxidation of CH3Br was studied at 210 °C and 230 °C, and it was found that the inhibition effect weakened with the increase in temperature. Additionally, Ru/TiO2 was also employed in the catalytic oxidation of CO, benzene, methyl acetate, and multi-pollutants of simulated PTA offgas.
研究领域:
环境化学
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催化科学
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大气污染控制
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DOI
高影响因子
MOLECULES
·
2023
·Vol. 28
·期 15
·5930
·
IF 4.6
Xuan Wang,Wei Liang,Changqing Lin,Tie Zhang,Jing Zhang,Nan Sheng,Zhaoning Song,Jie Jiang,Bing Sun,Wei Xu
Propane catalytic oxidation is an important industrial chemical process. However, poor activity is frequently observed for stable C–H bonds, especially for non-noble catalysts in low temperature. Herein, we reported a controlled synthesis of catalyst Co3O4@CeO2–IE via inverse loading and proposed a strategy of oxygen vacancy for its high catalytic oxidation activity, achieving better performance than traditional supported catalyst Co3O4/CeO2–IM, i.e., the T50(temperature at 50% propane conversion) of 217 °C vs. 235 °C and T90(temperature at 90% propane conversion) of 268 °C vs. 348 °C at the propane space velocity of 60,000 mL g−1h−1. Further investigations indicate that there are more enriched oxygen vacancies in Co3O4@CeO2–IE due to the unique preparation method. This work provides an element doping strategy to effectively boost the propane catalytic oxidation performance as well as a bright outlook for efficient environmental catalysts.Keywords:propane catalytic oxidation;inverse loading;oxygen vacancy
研究领域:
化学工程
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催化科学
✓ 已验证
DOI
PubMed
高影响因子
Molecular Catalysis
·
2024
·
IF 3.9
Yuwei Liang,Chunling Hu,Peng Chen,Qi Li,Jianning Wu,Zhiyong Liu,Jichang Liu,Yanlong Tai
5-hydroxymethylfurfural (HMF) can catalyte into 2,5-diformylfuran (DFF) which had received much attention as a potential biomass resource. Here, we used a simple and effective method to construct hollow CdS quantum dot (CdS QDs)/MIL-101 heterostructures with high contact area and multiple active sites. The structure of heterostructures could improve photocatalytic activity by charge transfer, photogenerated carrier separation and the multiple refractions of light supported within the hollow-structured CdS QDs. The detailed catalytic mechanism was illustrated by trap agent experiments and electron paramagnetic resonance (EPR) spectroscopy, in which superoxide radicals (·O 2 - ) play a decisive role in the catalytic oxidation of HMF to DFF. Furthermore, the large specific surface area of MIL-101 adsorbs O 2 from the reaction system thereby accelerating the ·O 2 - formation process. Under environmental conditions, 70 % CdS QDs/MIL-101 exhibited optimal catalytic performance. Comparing with pure CdS QDs, the photocurrent enhances 1.8 times, HMF conversion is 1.5 times and DFF selectivity is 1.2 times. This work provide a useful way to improve the conversion of biomass by Z-heterostructures under ambient conditions.
研究领域:
化学工程
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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
Catalysis Science & Technology
·
2018
·Vol. 8
·期 7
·1936-1944
·
IF 5.365
Zhongmin Liu,Yongchuan Wu,Jitao Chen,Yaru Li,Jingyu Zhao,Kaihua Gao,Ping Na
A bifunctional cake-like TiO2 was successfully synthesized via calcination of MIL-125(Ti) at a suitable temperature by a one-step method and was applied for As(III) removal by simultaneous photocatalytic oxidation and adsorption. The as-synthesized samples were characterized by XRD, TGA/DSC, SEM, TEM, N2 adsorption–desorption isotherms, PL spectra, photocurrent, FTIR and XPS. The effects of calcination temperature on the specific surface areas of the samples, transformation of the TiO2 crystal phase and properties of As(III) removal were investigated. The results showed that higher calcination temperature resulting in a lower specific surface area and more transformations of the TiO2 crystal phase from anatase to rutile. The TiO2 calcined at 380 °C (MIL-125(Ti)-380 °C) exhibited excellent properties for As(III) removal, including photocatalytic oxidation of As(III) and simultaneous adsorption of the generated As(V). In addition, MIL-125(Ti)-380 °C could be reused at least four times without significant reduction in the photocatalytic oxidation and adsorption performances. The excellent photocatalytic oxidation and adsorption abilities of MIL-125(Ti)-380 °C can be attributed to the synergistic effects of strong photogenerated electron–hole separation and high specific surface area. The bifunctional cake-like TiO2 provides a wonderful strategy to remove As(III) completely from contaminated water using a single step.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
Molecular Catalysis
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2020
·
IF 3.687
Yangyang Fang,Jun Li,Na Sheng,Xiaozhong Wang,Di Chen,Menglu Cai,Yu An,Yingqi Chen,Liyan Dai
A series of MoW-doped MCM-41 catalysts were prepared for the selective oxidation of anthracene to high value-added anthraquinone. Although anthraquinone production has been progressively industrialized, the anthracene oxidation still faces the problems of poor solubility of reactants and low anthracene conversion, particularly when employing supported catalysts in solution media. We herein reported a challenging but crucial method for anthraquinone production by using anthracene, H 2 O 2 and Mo 1 W 2 -MCM-41 catalyst in HOAc under mild reaction conditions. In addition, experimental and theoretical results revealed that the synergistic effect between Mo, W and MCM-41 species contributes to an enchanced cataltic activity with conversion up to 97.6 %. The highly active H 2 O 2 -MCM-41 catalyst can be used for several cycles without obvious activity loss and serve as a promising candidate for anthraquinone as well as its derivatives production, making it a good alternative for various oxidation reactions.
研究领域:
化学工程
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催化材料科学
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DOI
高影响因子
RSC Advances
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2019
·Vol. 9
·期 40
·23061-23070
·
IF 3.049
Libo Peng,Qinglong Xie,Yong Nie,Xuejun Liu,Meizhen Lu,Jianbing Ji
The oxidative cleavage of vegetable oils and their derivatives to produce bio-based aldehydes is a potentially useful process, although the aldehyde products are readily oxidized to carboxylic acids and thus seldom obtained in high yields. The present study developed a room-temperature method for the synthesis of bio-aldehydes via the oxidative cleavage of vegetable oil-derived epoxides, using H2WO4 as the catalyst, H2O2 as the oxidant, and t-BuOH as the solvent. Reactions were carried out at temperatures ranging from 25 to 35 °C for 3.5–10.5 h, and provided >99% conversion and >90% aldehyde yield. In particular, an approximately 97% yield was obtained at 25 °C after 10.5 h. As the reaction proceeded, the H2WO4 dissolved to form a W-containing anion. Several mesoporous Al-MCM-41 materials having different Si/Al ratios were hydrothermally synthesized and used as adsorbents to recover the catalyst by adsorbing these anions. The adsorption capacity of the Al-MCM-41 was found to increase with decreases in the Si/Al ratio. The Al-MCM-41 had little effect on the oxidative cleavage reaction at 25 °C, and thus could be directly added to the reaction system. The excellent anion adsorption performance of the Al-MCM-41 greatly improved the reusability of the H2WO4 catalyst. When using the Al-MCM-41 with the best adsorption performance, there was no significant decrease in the activity of the catalyst following five reuses.
研究领域:
化学工程
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生物化学
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材料科学
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DOI
PubMed
高影响因子
Catalysts
·
2019
·Vol. 9
·期 5
·408
·
IF 3.444
Chao Wang,Wenchao Hua,Guangtao Chai,Chuanhui Zhang,Yanglong Guo
Co3O4catalysts of cube and sphere shapes were prepared by one-step hydrothermal synthesis with different controlled amounts of Co(NO3)2·6H2O and NaOH. The morphological effects on both physicochemical properties and catalytic activities of vinyl chloride oxidation were investigated by material characterization and performance evaluation. The obtained results showed that the morphology, resulting in the exposure difference of crystal planes, significantly affected the catalytic property. The catalytic activity for vinyl chloride oxidation followed a descending order of Co3O4cube (Co3O4-c) > Co3O4sphere (Co3O4-s) > Co3O4commercial (Co3O4-com). The cube-shaped Co3O4presented higher catalytic activity and stability than Co3O4spheres despite their similar crystallographic structures as well as physicochemical and redox properties. Accordingly, the different catalytic behaviors should be attributed to a morphological effect. The Co3O4cube with a preferential exposure of (001) plane presented higher abundance of surface Co2+cations and adsorbed oxygen species, which acted as the active sites responsible for the improvement of its catalytic activity.Keywords:Co3O4;morphological effect;crystal plane;catalytic oxidation;vinyl chloride
研究领域:
化学
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材料科学
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产品关联
DOI
高影响因子
Nanomaterials
·
2023
·Vol. 13
·期 7
·1189
·
IF 5.3
Qingtao Li,Qi Cai,Xiaoyun Li,Enshan Han,Yanmin Sun,Yanfei Lu,Zhe Cai,Haibin Yu
To screen a suitable precursor, the effects of palladium salts on performance of Pd nanocatalysts for the oxidation of volatile organic components (VOCs) were investigated. A series of catalysts was prepared by impregnating Pd(NO3)2, PdCl2and Pd(NH3)4Cl2on alumina-coated cordierites. These catalysts were characterized by XRF, ICP-OES, XRD, N2adsorption-desorption, TEM, EDS, Raman spectroscopy, pulse-CO chemisorption, H2-TPR, NH3-TPD, and XPS. Pulse-CO chemisorption and TEM showed that Pd species formed by Pd(NO3)2have the highest metal dispersion (17.7%), while the other two were aggregating. For the same Pd loading, the higher the metal dispersion, the more the number of PdO species, so the number of PdO particles in the catalyst prepared from Pd (NO3)2is the largest. The catalytic oxidation activities of these catalysts were evaluated by ethane and propane. Based on a 99% conversion in the oxidation of ethane and propane at 598 K and 583 K, respectively, the catalyst prepared from Pd(NO3)2was considered to be the best performing catalyst. The chloride species in precursors can promote the aggregation of Pd species and poison the catalysts. The results show that Pd(NO3)2is more suitable as the precursor of VOC oxidation catalyst than PdCl2and Pd(NH3)4Cl2.Keywords:volatile organic components;palladium;catalytic oxidation;precursors
研究领域:
环境科学
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材料科学
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产品关联
DOI
PubMed
高影响因子
CATALYSIS TODAY
·
2019
·
IF 4.888
Hongxia Chen,Runduo Zhang,Wenjing Bao,Hao Wang,Zhoujun Wang,Ying Wei
The catalytic removal of HCHO with low noble-metal loading at room temperature is meaningful and challenging work. Herein, high performance catalysts x Pt/TS-1 (Si/Ti = 30, x = 0.1, 0.3, and 0.6 wt%) for HCHO oxidation were synthesized by polyvinyl alcohol-protected NaBH 4 reduction method. The Pt/TS-1 sample loading with 0.3 wt% Pt nanoparticles (NPs) could completely remove 120 ppm HCHO at space velocity (SV) of 60,000 mL/(g h) at 20 °C. Moreover, the 0.3Pt/TS-1 sample remained outstanding activity and stability in humid air with 35–75% water vapor and at high SV with a range between 60,000 and 240,000 mL/(g h). Based on the results of UV–vis, Raman, NH 3 -TPD, Contact angle measurement, CO chemisorption , and O 2 -TPD, the excellent catalytic performance of Pt/TS-1 was mostly attributed to high Pt dispersion and high concentration of adsorbed oxygen species. This work expands the field of utilization of zeolite supported noble-metal catalysts for the purification of indoor pollutants.
研究领域:
环境科学
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催化化学
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DOI
高影响因子
ENERGY & FUELS
·
2022
·
IF 4.654
Xue-Lei Duan,Yuan-Ming Cao,Chong Gao,Sheng-Li Niu,Yi-Wen Shen,Qi Guo,Jiao-Jiao Xie,Kai-Qiang He,Chun-Gang Yuan
One novel/multifunctional selenium-doped SrFeO3-δ/HNTs composite was fabricated and used for immobilization of gaseous mercury. The composite showed excellent performances for Hg0 removal via adsorption coupled with photocatalytic oxidation in visible-light conditions. The adsorption capacity of 4271.15 μg·g–1, rate of 5.0 μg·g–1·min–1, and removal efficiency of ∼100% were obtained under N2+O2, which was further confirmed by reaction kinetics. SrFeO3-δ was selenized into iron diselenide and a Se–Fe bond with high affinity toward Hg0. In addition, the yielding of •O2– and the separation of photoexcited electrons and holes (h+) promoted the photocatalytic oxidation of mercury. The composite with intrinsic magnetism could be easily recycled for reuse by magnetic separation. Moreover, the composite possessed favorable tolerance to the complicated flue gas. An online lab-built thermal decomposition system demonstrated that the immobilized Hg was primarily HgSe, which exhibited very high stability and low toxicity. Density functional theory (DFT) calculations proved that the composite was half metal with magnetism, indicating that Hg on Se-SrFeO3-δ/HNTs formed the stable structure releasing 1.055 eV. The doping of selenium promoted the charge transfer between O (2p) and Hg (6s), which also favored Hg0 removal. Se-SrFeO3-δ/HNTs with recyclability possess great potentials for Hg0 efficient removal and immobilization/detoxification from flue gas.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
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