CATALYSIS COMMUNICATIONS
·
2018
·
IF 3.463
Xiaoqiang Gao,Fang Zhang,Yi Yu,Yonghui Dou,Li Xu,Guoji Liu
Mo-modified V 2 O 5 /TiO 2 catalysts were prepared by wetness impregnation method and investigated for the selective oxidation of 2-methylnaphthalene to 2-naphthaldehyde. The catalysts were characterized by XRD, BET, XPS, and Raman to investigate the promotional effect of Mo on catalyst structure, surface property, and catalytic performance. The introduction of molybdenum decreases the amount of KVO 3 phase and enhances the dispersion of the vanadium phase. XPS and Raman results indicate that Mo prevents Sn and K to interact with V species and bonds with Ti or V through bridge oxygen. V1Mo1 sample demonstrates a remarkable improvement in conversion and selectivity compared with others.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2021
·
IF 5.706
Chenglin Feng,Xiaolong Liu,Tingyu Zhu,Yutao Hu,Mengkui Tian
Anatase TiO 2 loaded with 0.1wt.% Pt catalyst (0.1Pt/TiO 2 -A) was prepared via the impregnation method, and its CO catalytic oxidation activity was investigated. Noteworthy, introduction of H 2 O into the reaction atmosphere apparently facilitated the catalytic oxidation of CO. Besides, introduction of SO 2 inhibited the catalytic oxidation of CO. In presence of H 2 O and SO 2 , 0.1Pt/TiO 2 -A showed outstanding catalytic stability, and X-ray photoelectron spectroscopy (XPS) and thermogravimetric (TG) characterizations suggested that the amount of sulfate species deposited on the 0.1Pt/TiO 2 -A treated at 230 °C did not increase with time extension, which might be an important reason for the high sulfur resistance of 0.1Pt/TiO 2 -A. XPS results also demonstrated that the dissociation of H 2 O led to considerably increase of hydroxyl groups over the catalyst surface. H 2 18 O isotope-labeling experiments unambiguously showed that C 16 O 18 O was the main product accounting for 88.9%, revealing that the other oxygen atom in the product CO 2 was mostly from H 2 O. Consequently, based on previous researches and our experimental results, the mechanism of H 2 O promoting CO oxidation on 0.1Pt/TiO 2 -A catalyst was proposed.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2024
·
IF 4.4
Chengyang Sun,Yong Guo,Xiaohui Liu,Yanqin Wang
Plastics with inter-monomer C–C bond linkages comprise more than 70% of all plastics production, but their chemical recycling and upcycling usually require harsh conditions due to the inertness of C–C bonds, hindering their utilization efficiency. Here, we develop an oxidative upcycling strategy to convert polystyrene (PS) waste into benzoic acid over a NiO/TiO2 catalyst. This system is carried out in an environmentally friendly manner in an aqueous phase by using air as the oxidant, and up to 51.1% carbon yield of benzoic acid is obtained at 200 °C, 1 MPa air and 18 h. The conversion of real-life PS plastics is also successfully demonstrated. The reaction mechanism is further investigated by capturing radicals and intermediates during the oxidative reaction, confirming ·O2− radicals as the reactive oxygen species. A possible oxidative mechanism was proposed: the ·O2− radicals first activated the C–H bonds in the aliphatic portion of PS to generate carbonyl groups or CC bonds; then, through attack of the weak CC bonds, the polymer was constantly depolymerized to smaller oxygenated oligomers, dimers and finally the target product, benzoic acid. This work has provided a promising and green polystyrene upcycling strategy.
研究领域:
化学工程
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ACTA PHYSICO-CHIMICA SINICA
·
2024
·
IF 10.8
Zhuoyan Lv,Yangming Ding,Leilei Kang,Lin Li,Xiao Yan Liu,Aiqin Wang,Tao Zhang
Direct epoxidation of propylene (DEP) by molecular oxygen is an ideal way to synthesize propylene oxide (PO), yet it remains quite challenging. We demonstrated here that the PO formation rate and selectivity could be enhanced simultaneously through photo-thermo-catalysis over the CuO x /TiO 2 catalyst. At 180 °C, by introducing light, the PO formation rate increased more than 20-fold (from 8.2 to 180.6 μmol g −1 h −1 ) and the corresponding selectivity improved more than 3-fold (from 8 % to 27 %), breaking the traditional perception that the semiconductors exhibit very low reactivity for this reaction. Kinetic study results showed that the apparent activation energy for PO formation could sharply decrease under light irradiation (from 95 to 40 kJ mol −1 ). In situ electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) were applied to characterize the dynamics of the valence state of the copper oxide species and the activation intermediates of molecular oxygen. Evidence for the activation of oxygen, which could direct to the PO formation pathway, was captured. The light-driven electrons could promote the formation of active Cu + , which could form the side-on μ-peroxo Cu(II) 2 structure, weaken the O–O bond, and improve the PO formation rate and selectivity. This work paves a new way for designing semiconductor-supported photocatalysts for DEP reactions with molecular oxygen.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
ChemCatChem
·
2021
·Vol. 13
·期 18
·3953-3959
·
IF 5.686
Zhiming Zhou,Hongyan Jia,Yong Guo,Yangang Wang,Xiaohui Liu,Qineng Xia,Xi Li,Yanqin Wang
Graphical Sulfates : The introduction of sulfates into TiO 2 supported Pt-WO x catalyst greatly improves the dispersion of Pt and WOx species, increases the acid amount and inhibits the leaching of Pt and WO x species, resulting in dramatically promoted catalytic activity and stability for glycerol hydrogenolysis to 1,3-PDO and n-PO with 93 % total yield. Pt-WO x based catalysts were widely investigated and showed high industrial application potential for glycerol hydrogenolysis. Further improving the catalytic activity and stability of the Pt-WO x based catalysts is important. Herein, we modified the TiO 2 supported Pt-WO x catalyst with sulfate doping and employed for the glycerol hydrogenolysis. The introduction of sulfates dramatically promoted the catalytic activity and stability of the Pt/W/Ti catalyst in glycerol hydrogenolysis. Sulfates-doped Pt/W−S/Ti achieved 100 % conversion of glycerol, with 36 % selectivity to 1,3-PDO and 57 % selectivity to n-PO at 120 °C and 4 MPa, while the conversion over Pt/W/Ti only reached 57 %. Moreover, Pt/W−S/Ti offered 22.5 times more glycerol conversion (90 %) than Pt/W/Ti (4 %) for the second run. The much higher activity of the Pt/W−S/Ti was ascribed to the better dispersion of Pt and WO x species and more Brønsted acid amount. The enhanced stability of Pt/W−S/Ti was attributed to its strong anti-leaching ability after sulfate doping.
研究领域:
催化化学
·
工业化学
·
材料科学
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2024
·
IF 10.8
Wei Chen,Juan Zheng,Yarong Fang,Yutao Wang,Jinpeng Hu,Yuhua Zhu,Xiaoxiao Zhu,Weihao Li,Qian Zhang,Chuanqi Pan,Baojian Zhang,Xiaofeng Qiu,Sibo Wang,Shuang Cui,Jinlong Wang,Jinsong Wu,Zhu Luo,Yanbing Guo
Typically, SO2 unavoidably deactivates catalysts in most heterogeneous catalytic oxidations. However, for Pt-based catalysts, SO2 exhibits an extraordinary boosting effect in propane catalytic oxidation, but the promotive mechanism remains contentious. In this study, an in situ-formed tactful (Pt–S–O)-Ti structure was concluded to be a key factor for Pt/TiO2 catalysts with a substantial SO2 tolerance ability. The experiments and theoretical calculations confirm that the high degree of hybridization and orbital coupling between Pt 5d and S 3p orbitals enable more charge transfer from Pt to S species, thus forming the (Pt–S–O)-Ti structure with the oxygen atom dissociated from the chemisorbed O2 adsorbed on oxygen vacancies. The active oxygen atom in the (Pt–S–O)-Ti active structure is a robust site for C3H8 adsorption, leading to a better C3H8 combustion performance. This work can provide insights into the rational design of chemical bonds for high SO2 tolerance catalysts, thereby improving economic and environmental benefits.
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Guangyue Xu,Chuang Li,Tianyu Deng,Chenguang Wang,Ying Zhang,Yao Fu
The conversion of levulinic acid (LA) to γ-valerolactone (GVL) is one of the most important reactions from biomass-derived platform chemicals to value-added chemicals. In this work, bimetallic PdRu/TiO2 catalyst compared to monometallic Ru/TiO2 was designed for the conversion of LA to GVL at ambient H2 pressure. The highly dispersed Pd affected the reaction by two antagonistic effects: (I) increasing the reaction rate by promoting the activation of H2; (II) decreasing the reaction rate by lowering the activation ability of carbonyl group over Ru. The kinetic analysis refined by H2 concentration showed much lower apparent activation energy over 0.2Pd1Ru/TiO2 than that over Ru/TiO2. Finally, the catalysts were evaluated by both GVL productivity and catalyst cost to show increasing benefit of Pd addition at lower H2 pressure. This study offers both theoretical foundation and application instructions for high efficiency conversion of LA to GVL under mild conditions, especially ambient H2 pressure.
研究领域:
催化化学
·
生物质能
·
绿色化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Yi Yu,Fanfan Li,Xinghao Han,Shanghai Long,Shishuai Shi,Li Xu,Guoji Liu
2-Naphthaldehyde is industrially produced from 2-naphthalene nitrile and 2-naphthoyl chloride in acid. Greener gas-solid catalytic oxidation of 2-methylnaphthalene to 2-naphthaldehyde has rarely been investigated. In this study, the preparation of 2-naphthaldehyde over V/TiO2 catalysts doped with 13 metal promoters was explored and the V-Cu(1)/TiO2 catalyst showed excellent performance with 63.37% 2-methylnaphthalene conversion and 70.09% 2-naphthaldehyde selectivity at 400 °C, gas hourly space velocity (GHSV) of 10 000 h–1, and feed flow rate of 3.87 × 10–4 mol·h–1, giving the highest turnover frequency (TOF) value of 17.05 × 10–6 s–1. We have consequently studied the effect of Cu doping on the physicochemical properties of the V/TiO2 catalyst and found that structural changes are not the main reason to improve the catalytic performance. Increased vacancies and oxygen mobility accelerate the formation of nucleophilic oxygen from electrophilic oxygen, which are the key factors to improve 2-NA selectivity. The synergy between V, Cu, and O through the V–O–Cu bridging bond also improves the weak acid ratio, redox ability, and the reactivity of active sites (bridging and terminal oxygen). X-ray photoelectron spectroscopy (XPS), in situ diffuse-reflectance infrared Fourier transform (DRIFT) spectroscopy, and density-functional theory (DFT) calculations have proved that this reaction obeys the Mars–van Krevelen mechanism and involves a reduction process of V5+ and Cu2+ during oxidation.
研究领域:
催化化学
·
理论化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2018
·
IF 4.521
Xiao Chen,Zhenglong Zhao,Ying Zhou,Qiulian Zhu,Zhiyan Pan,Hanfeng Lu
This study presents an efficient, economic, and simple preparation strategy for Pt/TiO 2 monolith catalysts. Nano-Pt/TiO 2 dispersion liquid with good activity and stability was synthesized by hydrolysis and chemical reduction method. Various Pt/TiO 2 monolithic catalysts were prepared by spraying the dispersion liquid on different substrates. Results of transmission electron microscopy, scanning electron microscopy, N 2 adsorption-desorption, H 2 temperature-programmed and CO oxidation showed that the Pt/TiO 2 nanoparticles with good mesoporous structure and redox properties were highly dispersed on the substrate. The as-prepared 0.5 Pt/TiO 2 cordierite monolithic catalyst with 0.1 wt‰ Pt content exhibited excellent catalytic combustion activity ( T 90 of toluene combustion was 212 ℃), stability (no deactivation was observed during a 120 h test) and firmness (mass loss was 0.11% after 1 h ultrasonic vibration) under experimental conditions. Compared with state-of-the-art methods, this method is more suitable for large-scale production of waste-gas-treated monolith catalysts. And this method meets the concept of energy saving and emission reduction because of its simplicity, high efficiency, environmental friendliness, and high utilization of active components.
研究领域:
环境科学
·
催化材料
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Zhi Liu,Chong Chen,Jinchong Zhao,Lingzhi Yang,Kaian Sun,Lingyou Zeng,Yuan Pan,Yunqi Liu,Chenguang Liu
Selective catalytic reduction of NO by NH 3 (SCR) at low temperature usually considered to be the combination of NO oxidation and “Fast SCR” process. However, the NO oxidation mechanism and the role of NO 2 over “Fast SCR” process are controversial. Focusing on these problems, the in-deep studies were performed over the typical MnO x /TiO 2 catalysts. Combining in-situ DRIFT, TPD-MS and DFT calculation results, an integrated NO oxidation mechanism was proposed based on an “Nitro-assisted oxygen activation” concept where the activation and transformation of O 2 is linked with the transformation of nitro species. The O O bond of O 2 can be weakened by generating a variation of bidentate nitrates, which can promote the break of O O bond and the formation of NO 2 . The formation of the variation of bidentate nitrates was the rate-determining step over NO oxidation. Additionally, we further reveal that the crucial role of NO 2 over “Fast SCR” process lies in participating the hydrogen abstraction from coordinated NH 3 and promoting the production of NH 2 active species which can direct react with NO to generate N 2 and H 2 O. The removability of NO 2 can coupling the MnO 2 (NO oxidation active component) and TiO 2 support (“Fast SCR” active component) together. Our findings provide insight into the design and improvement of catalysts or reaction pathways over the low-temperature SCR process.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Chuanzhi Sun,Hao Liu,Wei Chen,Dezhan Chen,Shuohan Yu,Annai Liu,Lin Dong,Shuai Feng
A series of Sm- and/or Zr-doped MnO x -TiO 2 catalysts were prepared, and the catalysts exhibited better N 2 selectivity and SO 2 resistance than the undoped MnO x -TiO 2 catalyst for the selective catalytic reduction of NO by NH 3 (NH 3 -SCR). The reasons for the good N 2 selectivity and SO 2 resistance of the catalysts were proposed. X-ray photoelectron spectroscopy (XPS) combined with density functional theory (DFT) calculations suggested that electron transfer between the manganese and samarium species by Mn 4+ + Sm 2+ ↔ Mn 3+ + Sm 3+ redox cycles occurred in the Sm-containing catalysts. Furthermore, electron transfer from Sm 2+ to Mn 4+ suppressed electron transfer from NH 3 to Mn 4+ , inhibiting the formation of NH 2 or NH. Thus, the pathway for NH generation was removed, and the reaction of 2NH + 4NO → 3N 2 O + H 2 O was prevented. Consequently, the N 2 selectivity of the NH 3 -SCR reaction was enhanced. In situ diffused reflectance infrared Fourier transform spectroscopy ( in situ DRIFTS) combined with thermogravimetry, differential scanning calorimetry and mass spectrometry (TG-DSC-MS) results revealed that the deposition rate of sulfate species decreases after Sm doping, which was also attributed to the suppressed electron transfer from SO 2 to Mn 4+ , i.e., the oxidation of SO 2 to SO 3 . Thus, the catalysts exhibited better SO 2 resistance.
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2020
·
IF 5.825
Zhen-Hong He,Chong-Shan Jiang,Kuan Wang,Zhong-Yu Wang,Na Li,Wei-Tao Wang,Zhao-Tie Liu
Catalytic conversion of CO 2 into methanol is of particular interest as it does not only provide valuable methanol, but also utilize the waste CO 2 . In the present work, a CoO/Co/TiO 2 catalyst was developed and utilized in catalyzing CO 2 to methanol under photothermal conditions. From the results of characterization, the supported Co nanoparticles (NPs) were composed of Co 0 in the bulk, CoO film formed from air oxidation on the surface, and Co 0 at Co NPs-TiO 2 interfaces. This structure provided the possibility for a Z scheme photothermal catalytic system, which revealed a high activity for methanol formation in aqueous media under atmosphere pressure. It was proposed that the light excited electrons from the valence band (VB) of TiO 2 , and the excited electrons could enhance the Co 0 catalytic activity under thermal conditions. The present approach will offer a new strategy to design Co based Z scheme catalysts and further improve the conversion efficiency from CO 2 to fuels.
研究领域:
化学
·
环境科学
✓ 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）