Molecular Catalysis
·
2024
·
IF 3.9
Wen-Xia Zhang,Xi Zhao,Lin-Ya Xu,Shuang Xia,Yu-Fen Zhou,Chong-Lai Chen,Hai-Hua He,Meng-Fei Luo,Jian Chen
The surface Pt species and adsorbed oxygen on the Pt/ZrO 2 catalyst were successfully modulated by altering the preparation methods, resulting in distinct catalytic behaviors for CO, n-heptane, and toluene oxidation. The Pt/ZrO 2 catalyst was initially prepared via wetness impregnation and subsequently reduced in an H 2 atmosphere to obtain the Pt/ZrO 2 -R catalyst. In contrast, the Pt/ZrO 2 -E catalyst was synthesized using ethanol solvent (also serving as a reducing agent) instead of water during wetness impregnation. Moreover, the pre-prepared Pt nanoparticles were loaded onto the ZrO 2 surface using polyvinylpyrrolidine (as a protective and structure directing agent) dissolved in ethanol solvent to fabricate the Pt/ZrO 2 -EP catalyst. Among these catalysts, the Pt/ZrO 2 -R exhibits superior catalytic activity towards CO oxidation due to its abundant metallic Pt species. It is found that activity of Pt/ZrO 2 catalyst for n-heptane oxidation is positively correlated with its surface adsorbed oxygen concentration, thus the highest activity is achieved over the Pt/ZrO 2 -EP catalyst possessing a higher concentration of surface adsorbed oxygen species. Unlike CO and n-heptane oxidation, toluene oxidation activity is affected by multiple factors, it is primarily promoted by synergistic catalysis between metallic Pt species (Pt 0 ) and surface adsorbed oxygen species over the Pt/ZrO 2 -EP catalyst. Our preliminary findings underscore that precise modulation of sensitive active sites on surfaces plays a critical role in specific catalytic reactions.
研究领域:
催化化学
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Benyong Yang,Wentao Mu,Benedict Tsz Woon Lo,Sijie Liu,Zhihang Chen,Liam John France,Xuehui Li
NOx and CO formation is, at present, a consequence arising from fuel production, but their emission need not be. In this study, a series of novel Ir-containing TiO2-nanobelt catalysts were designed and prepared for the simultaneous removal of NOx and CO. Activity data demonstrates that the TiO2(B) support promotes NO reduction compared to anatase. Furthermore, reaction efficiency (RE), a measure of NOx consumption vis-à-vis that of CO, reveals that catalysts containing anatase promote CO oxidation more so than their TiO2(B) counterparts. Increasing Ir concentration over the latter promotes low-temperature catalytic performance, an effect believed to be linked to the formation of Ir0–IrO2 composites. In situ DRIFTS experiments reveal the relevance of nitrite/nitrate formation and consumption at 250 °C, a mechanism insinuated by the RE value. However, at 300 °C, both TOF and RE increase, signifying the participation of a faster and more-selective reaction, which appears consistent with the isocyanate-mediated pathway.
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
Journal of Inorganic and Organometallic Polymers and Materials
·
2020
·Vol. 30
·期 11
·4350-4360
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IF 1.941
Zhang Zhihua,Peng Xinke,Zhang Zhongping,Xiao Weiming,Deng Shengjun,Mao Xuejin,Hong Sanguo,Chen Chao,Zhang Ning
Metal–organic framework (MOF) supported nanocatalysts are attracting great attentions in heterogeneous catalysis. However, they are still less explored and poorly understood in catalyzing solid–gas reactions. In current work, two MOF supported Pt nanocatalysts were prepared by immersion method coupled with the most commonly used NaBH 4 (Pt/UiO-66-NaBH 4 ) and H 2 (Pt/UiO-66-H 2 ) reduction, and their catalytic CO oxidation performances were investigated. NaBH 4 and H 2 reduction both provide highly dispersed Pt/UiO-66 nanocatalysts, and the two prepared catalysts display excellent CO oxidation activities. Moreover, CO oxidation durability tests reveal that Pt/UiO-66-NaBH 4 shows superior durability and structure stability, which are much better than those of Pt/UiO-66-H 2 . The high structure stability of Pt/UiO-66-NaBH 4 also endows it with good H 2 O and CO 2 tolerance. This work attempts to elucidate the influence of reduction methods on the structures and catalytic CO oxidation performances of Pt/UiO-66 catalysts by employing XRD, TEM, N 2 -sorption, XPS and in situ DRIFTS techniques. Furthermore, the mechanism of CO oxidation was studied by in situ DRIFTS, and the result reveals that the CO oxidation on the two catalysts follows different mechanism.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
Progress in Natural Science-Materials International
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2016
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IF 1.753
Yu Bai,Chunlei Wang,Xingyi Zhou,Junling Lu,Yujie Xiong
Pd typically exhibits relatively low catalytic activity in CO oxidation, as CO is apt to be adsorbed on Pd to poison the surface for O 2 activation. In this Letter, we report that this limitation can be overcome by integrating Pd with TiO 2 . The TiO 2 was coated on Pd nanocubes with a controllable thickness using atomic layer deposition (ALD) method. Given the different work functions of TiO 2 and Pd, the electrons in TiO 2 semiconductor will flow toward Pd. With the electron density increased on Pd, the adsorption of CO to Pd will be weakened while the oxygen activation can be facilitated. Meanwhile, the interface-confined sites at Pd-TiO 2 may further enhance the oxygen activation. As the species adsorption and activation are strongly correlated with electron density, the performance of Pd-TiO 2 in CO oxidation turns out to depend on the TiO 2 thickness, which determines the number of transferred electrons, within a certain range (<1.8 nm). This work provides a new strategy for enhancing catalytic performance through tailoring charge densities in hybrid catalysts.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS LETTERS
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2022
·Vol. 152
·期 12
·3843-3852
·
IF 2.936
Huang Xuehui,Yang Na,Li Xiaobo,Pan Hongyun,Song Xiaozhan,Chang Yu
La 0.8 Sr 0.2 MnO 3 (LSM) catalyst has been successfully prepared by solid phase method (G-LSM-T), sol–gel method (C-LSM-T) and molten salt method (S-LSM-T), using as-prepared MnCO 3 microspheres as templates, respectively. It was shown that the S-LSM-550 catalyst presented well-formed perovskite structures, large specific surface area (49.65m 2 /g) and promising catalytic activity in CO oxidation, which T 50 and T 90 for CO conversion over fresh S-LSM-550 were 145.14 °C and 170.73 °C. The S-LSM-550 calcined at 550 °C for 2 h exhibited excellent thermal stability and catalytic activity compared with the samples prepared by solid phase method and sol–gel method. Its superior catalytic performance could be greatly attributed to its stable microstructure, high surface Mn 4+ /Mn 3+ molar ratio and more available surface adsorbed oxygen species. Graphical Abstract
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 5
·2343-2352
·
IF 3.049
Feng Zhao,Shuangde Li,Xiaofeng Wu,Renliang Yue,Weiman Li,Yunfa Chen
CuO–CeO2 nanocatalysts with different amounts of Mn dopping (Mn/Cu molar ratios of 0.5 : 5, 1 : 5 and 1.5 : 5) were synthesized by flame spray pyrolysis (FSP) method and tested in the catalytic oxidation of CO. The physicochemical properties of the synthesised samples were characterized systematically, including using X-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FESEM), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), oxygen-temperature programmed desorption (O2-TPD), hydrogen-temperature programmed reduction (H2-TPR) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). The results showed that the 1Mn–Cu–Ce sample (Mn/Cu molar ratio of 1 : 5) exhibited superior catalytic activity for CO oxidation, with the temperature of 90% CO oxidation at 131 °C at a high space velocity (SV = 60 000 mL g−1 h−1), which was 56 °C lower than that of the Cu–Ce sample. In addition, the 1Mn–Cu–Ce sample displays excellent stability with prolonged time on CO stream and the resistance to water vapor. The significantly enhanced activity was correlated with strong synergetic effect, leading to fine textual properties, abundant chemically adsorbed oxygen and high lattice oxygen mobility, which further induced more Cu+ species and less formation of carbon intermediates during the CO oxidation process detected by in situ DRIFTS analysis. This work will provide in-depth understanding of the synergetic effect on CO oxidation performances over Mn doped CuO–CeO2 composite catalysts through FSP method.
研究领域:
催化化学
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材料科学
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环境科学
✓ 已验证
DOI
高影响因子
Nanoscale Research Letters
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2020
·Vol. 15
·期 1
·1-15
·
IF 3.578
Fan Li,Sun Qi,Zheng Wei,Tang Qinyuan,Zhang Ting,Tian Mengkui
The rutile Sn x Ti 1− x O 2 ( x = 0, 0.33, 0.5, 0.67, 1) solid solution was synthesized by a one-step hydrothermal method, in which tetrabutyl titanate and Tin (IV) chloride pentahydrate were used as raw materials. A series of Ru/Sn x Ti 1− x O 2 were then prepared by the impregnation process in RuCl 3 to investigate the performance and stability of CO and C 3 H 8 oxidation. These catalysts were characterized through XRD, N 2 adsorption-desorption, FT-IR, TEM, XPS, H 2 -TPR, and O 2 -TPD techniques. The effect of Sn/Ti molar ratio and hydrothermal condition on the low-temperature catalytic oxidized performance and stability of Ru/Sn x Ti 1− x O 2 were investigated. The results indicated that Ru/Sn 0.67 Ti 0.33 O 2 catalyst showed an excellent activity and stability at low temperatures. The CO conversion reached 50% at 180 °C and 90% at 240 °C. Besides, the C 3 H 8 conversion reached 50% at 320 °C, the complete conversion of C 3 H 8 realized at 500 °C, and no deactivation occurs after 12 h of catalytic reaction. The excellent low-temperature activity and stability of the Ru/Sn 0.67 Ti 0.33 O 2 were attributed to the following factors. Firstly, XRD results showed that Sn 4+ was successfully introduced into the lattice of TiO 2 to replace Ti 4+ forming a homogeneous solid solution (containing –Sn 4+ –O–Ti 4+ – species), which was consistent with TEM and N 2 adsorption-desorption results. The introduction of Sn could suppress the growth of anatase crystal and promote the formation of rutile phase, and this phase transition was helpful to improve the low-temperature activity of the catalysts. Secondly, TEM images showed that ultrafine Ru nanoparticles (~ 5 nm) were dispersed on Sn 0.67 Ti 0.33 O 2 support, suggesting that the formation of Sn x Ti 1− x O 2 solid solution was beneficial to the dispersion of Ru particles.
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
Scientific Reports
·
2019
·Vol. 9
·期 1
·1-14
·
IF 4.011
Dong Fang,Meng Yu,Han Weiliang,Zhao Haijun,Tang Zhicheng
Here, we synthesized a series of Cu/CeO 2 catalysts with different morphology and size, including Cu/CeO 2 nanospheres (Cu/CeO 2 -S), Cu/CeO 2 nanoparticles (Cu/CeO 2 -P), Cu/CeO 2 nanorods (Cu/CeO 2 -R) and flower-like Cu/CeO 2 microspheres (Cu/CeO 2 -F) to systematically explore the structure-activity relationship in CO oxidation. Crucially, the effect of morphology, crystal size, Ce 4+ /Ce 3+ species, oxygen vacancies derived from the removal of lattice oxygen (O latt ) species in CeO 2 and lattice defect sites on CO activity was revealed through various characterizations. It was clearly discovered that the activity of these catalysts was as follows: Cu/CeO 2 -R > Cu/CeO 2 -P > Cu/CeO 2 -S > Cu/CeO 2 -F, and the Cu/CeO 2 -R catalyst preferentially showed the best catalytic performance with a 90% conversion of CO even at 58 °C, owned the smaller particles size of CeO 2 and CuO, and exhibited the higher concentration of O latt species and oxygen vacancies. Besides, it is also verified that the Cu/CeO 2 -F sample exhibited the larger CeO 2 crystal size (17.14 nm), which led to the lower Cu dispersion and CO conversion, even at 121 °C (T 90 ). Most importantly, we discovered that the amount of surface lattice defect sites was positively related to the reaction rate of CO. Simultaneously, DFT calculation also demonstrated that the introduced oxygen vacancies in CeO 2 could accelerate the oxidation of CO by the alteration of CO adsorption energy. Therefore, the morphology, the crystal size, the content of oxygen vacancies, as well as lattice defects of Cu/CeO 2 catalyst might work together for CO oxidation reaction.
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
ACS Catalysis
·
2015
·
IF 9.312
Kunfeng Zhao,Hailian Tang,Botao Qiao,Lin Li,Junhu Wang
Au/γ-Fe2O3 and Au/α-Fe2O3 catalysts with identical size of Au nanoparticles, chemical state of Au species, and amount of surface OH– group were prepared. The Au/γ-Fe2O3 catalyst exhibited exceptionally high activity, regardless of the heat treatments. The CO-TPR, sequential pulse reaction, and in situ Raman spectra demonstrate that the much higher activity of Au/γ-Fe2O3 originated from its higher redox property at low temperature. Systematic study shows that this higher-redox-property-based higher activity could be extended to γ-Fe2O3-supported Pt-group metals and to other reactions that follow Mars–Van Krevelen mechanism. This finding may provide a new avenue for catalyst improvement or development by choosing the suitable crystal phase of the oxide support.
研究领域:
催化化学
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材料科学
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表面科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2015
·Vol. 50
·期 19
·6339-6348
·
IF 2.371
He Beibei,Zhao Qingguo,Zeng Zhigang,Wang Xiaohong,Han Sheng
Au@CeO 2 core–shell nanostructure catalysts were synthesized by hydrothermal reaction method. The effect of hydrothermal reaction time and calcination temperature on the textural and morphological characteristics of the catalyst was investigated by TEM, SEM, XRD, XPS, ICP, UV–Vis, and N 2 adsorption–desorption techniques. The results proved that gold core and CeO 2 shell formed simultaneously at the beginning of the reaction. By extending the hydrothermal reaction time, both the grain size of Au core and CeO 2 shell increased. The crystallization degree of CeO 2 and the interaction between Au and CeO 2 were also enhanced. The 90 % CO conversion temperature (T 90 % ) of Au@CeO 2 declined from 187 to 142 °C with the hydrothermal reaction time extended from 6 to 20 h. After 70-h reaction, the catalytic activity was still maintained without any loss. The effect of the calcination temperature on the catalytic performance was also investigated and it turned out that high calcination temperature has a positive influence on the catalytic activity. The likely active sites are the interface between Au core and CeO 2 shell. Gold content, metal–support interaction (MSI), and oxygen vacancy are all related to the activity. The excellent performance of 20 h-600 °C-Au@CeO 2 in catalytic activity and stability results from the joint effects of these triple factors.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2017
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IF 2.429
Linying Du,Weiwei Wang,Han Yan,Xu Wang,Zhao Jin,Qisheng Song,Rui Si,Chunjiang Jia
Copper-ceria sheets catalysts with different loadings of copper (2 wt.%, 5 wt.% and 10 wt.%) supported on ceria nanosheets were synthesized via a deposition–precipitation (DP) method. The prepared catalysts were systematically characterized with various structural and textural detections including X-ray diffraction (XRD), Raman spectra , transmission electron microscopy (TEM), X-ray absorption fine structure (XAFS), and temperature-programmed reduction by hydrogen (H 2 -TPR), and tested for the CO oxidation reaction. Notably, the sample containing 5 wt.% of Cu exhibited the best catalytic performance as a result of the highest number of active CuO species on the catalyst surface. Further increase of copper content strongly affects the dispersion of copper and thus leads to the formation of less active bulk CuO phase, which was verified by XRD and H 2 -TPR analysis. Moreover, on the basis of in-situ diffuse reflectance infrared Fourier transform spectroscopy ( in-situ DRIFTS) results, the surface Cu + species, which are derived from the reduction of Cu 2+ , are likely to play a crucial role in the catalyzing CO oxidation. Consequently, the superior catalytic performance of the copper-ceria sheets is mainly attributed to the highly dispersed CuO x cluster rather than Cu-[O x ]-Ce structure, while the bulk CuO phase is adverse to the catalytic activity of CO oxidation.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Xing Yuan,Lingquan Meng,Chaohe Zheng,Haibo Zhao
Perovskites have been recognized as affordable substitutes for noble-metal catalysts for their tunable catalytic activity and thermal stability. Nevertheless, the highly demanding synthesis procedure still hinders the application of perovskites in catalytic combustion. In this work, a series of nanostructured SiTiO3 perovskites with B-site partial substitution by Co, Fe, Mn, Ni, and Cu are synthesized via flame spray pyrolysis in one step. The comprehensive characterizations on textural properties of nanostructured perovskites reveal that the flame-made perovskite nanoparticles all exhibit high crystal purity and large specific surface area (∼40 m2/g). Furthermore, the highest catalytic activity is achieved by SrTi0.5Co0.5O3 due to the formation of favorable oxygen vacancies, outstanding reducibility, and oxygen desorption capability. Additionally, the presence of 10 vol % water vapor during long-term testing indicates remarkable durability and water resistance. Finally, the CO oxidation and CH4 dehydrogenation on SrTiO3 incorporating Co atoms are more thermodynamically and kinetically favorable than those on other doped surfaces.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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