Journal of Physical Chemistry C
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2021
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IF 4.126
Yanye Zhu,Fangyuan Zhou,Xiaoqiang Wang,Yue Liu,Zhongbiao Wu
The NH3–SCR process could provide cobenefits for VOCs abatement from industrial sources. Ceria-based catalysts have received considerable attention for NOx removal at low-medium temperatures. In this study, the reaction behaviors of the simultaneous control of NOx and methanol over the Sb0.5CeZr2Ox catalyst were investigated. It was found that the presence of methanol reduced NOx conversion at low temperatures, while the methanol mineralization rate was promoted in the SCR reaction environment. This effect weakened as the temperature increased, and both NOx and methanol could be effectively removed (with efficiencies more than 90%) within 250–350 °C at a CH3OH/NO ratio of no more than 1:1. NO adsorption and oxidation were greatly suppressed by methanol, thereby inhibiting the SCR reaction via the Langmuir–Hinshelwood (L-H) mechanism. Meanwhile, the formation of formamide via NH3 and intermediates of methanol oxidation was also responsible for the deactivation effect on the SCR reaction at low temperatures. The presence of NO was found to be the main reason for enhanced methanol deep oxidation as NO can promote the rehealing process of active oxygen species.
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
NEW JOURNAL OF CHEMISTRY
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2025
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IF 2.5
Lei Dong,Yangyang Yuan,Shengjie Zhu,Peidong Li,Xiaomin Zhang,Yanping Chen,Lei Xu
Direct synthesis of dimethyl carbonate (DMC) using CO2 and methanol as raw materials is an environmentally friendly and promising route for recycling carbon sources from exhaust gases. Herein, well-constructed CeO2-based nanoparticle catalysts promoted by various Fe contents were synthesized via a facile co-precipitation method and demonstrated to be highly effective for direct DMC synthesis. The uniform doping of iron species in ceria lattice resulted in the formation of more surface oxygen vacancies, and thereby more coordinatively unsaturated surface metal cations and lattice oxygen anions were generated, which served as the Lewis acidic-basic sites required for the reaction. Based on in-situ DRIFTS results, it was deduced that the oxygen vacancies played a crucial role in activating CO2 to reactive bidentate carbonates and the formation of active terminal methoxy intermediates was also enhanced by Fe incorporation. Consequently, the maximum DMC yield of 3.84 mmol h-1 g-1 cat was obtained on Fe0.04Ce0.96Ox under relatively mild reaction conditions of 130 °C and 3.0 MPa. Additionally, in the tandem reaction system using 2-cyanopyridine (2-CP) as a dehydrating agent, the catalytic activity for 2-CP hydration was found to be closely associated with the total basicity of the catalysts, and in turn a higher hydration rate was more conducive to the DMC synthesis through enhancing in-situ water removal efficiency. As expected, the present work provides in-depth insights into the structure-performance relationship of Fe-modified ceria-based catalysts for direct DMC synthesis from CO2 and methanol, and offers meaningful guidance for the advancement of highly efficient catalysts.
研究领域:
化学工程
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环境科学
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DOI
高影响因子
JOURNAL OF CATALYSIS
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2022
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IF 8.047
Biyun Fang,Zeliang Qi,Fangming Liu,Chuanfeng Zhang,Chunyan Li,Jun Ni,Jianxin Lin,Bingyu Lin,Lilong Jiang
The development of efficient oxides-supported bimetallic catalysts is critical for ammonia synthesis or other catalytic reactions. Herein, the design of ceria-supported Co-Mo bimetallic catalysts with different properties is performed by changing Mo addition to enhance the ammonia synthesis activities. It is found that the reduction of ceria and molybdenum oxide would be boosted by Co species, but the reduction of the bimetallic catalyst would be inhibited by the aggregated molybdenum oxide for the catalyst with Co and Mo simultaneous addition. On the contrary, this ill effect of molybdenum oxide on the reduction of the bimetallic catalyst can be effectively alleviated by the subsequent addition of Mo species to ceria-supported Co catalyst, resulting in enhancement of the proportion of Co metal, Ce 3+ and low-valent Mo species, as well as surface enrichment of Co species. In such cases, the amount of the adsorbed hydrogen and nitrogen species would increase, and hydrogen species preferentially desorbs following a pathway of H 2 formation. As a result, the catalyst obtained by the separate addition of Co and Mo shows 2.5-fold more active than its counterpart with the simultaneous addition of Co and Mo species. These findings provide a valuable insight in designing reducible oxide-supported bimetallic catalysts in ammonia synthesis or other hydrogen-involved reactions.
研究领域:
催化化学
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材料科学
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DOI
高影响因子
ChemistrySelect
·
2023
·Vol. 8
·期 5
·e202204745
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IF 2.1
Mingwei Wu,Wenzhi Li,Chen Zhu,Wenjian Wu,Lulu Zhang,Taimin Zheng,Yan Fu,Liang Yuan
Graphical Here, direct oxidation of methane to methanol under gaseous condition on iridium promoted Cu/CeO 2 catalyst, prepared using a sol-gel method, is investigated. As for proposed reaction mechanism, it is believed that the CuO−IrO 2 phase is the active sites, while CeO x matrix should act as the auxiliaries, providing active oxygen (O − , O 2 2− , O 2 ⋅ − ) during the methane oxidation reaction. The role of IrO 2 is to activate CH 4 molecule and make Cu-attached O more fragile to be released through the interaction of IrO 2 and CuO, and CuO works to help generate surface methoxyl, so as to improve the methanol yield and selectivity. Single-step conversion of methane to methanol in the gaseous phase is required for high value added application of methane and environmental protection, but it is challenging. Here, direct oxidation of methane to methanol under gaseous condition on iridium promoted Cu/CeO 2 catalyst, prepared using a sol-gel method, is investigated. The addition of iridium can effectively upgrade the redox properties and oxygen storage capacity due to intense metal interaction, stimulating a prominent catalytic performance for methane conversion to methanol on Cu−Ir@CeO 2 catalyst. Approximately 26.2 μmol/g cat methanol yield and 68 % methanol selectivity are achieved on the trimetallic 5Cu0.5Ir@CeO 2 catalyst at 550 °C in 2 h. Consequences of the analysis of XRD, SEM, HRTEM, Raman, FI-IR and XPS demonstrate that highly-dispersed Ir and Cu species are uniformly distributed on CeO 2 surface, and partial Cu or Ir atoms replace Ce 4+ in CeO 2 lattice due to the metal interaction in the colloidal structure, which can impact the catalyst's electronic properties. H 2 temperature-programmed reduction (H 2 -TPR) and CH 4 temperature-programmed desorption (CH 4 -TPD) results disclose that the unique ternary surface exhibits excellent redox properties and strong adsorption capacity for methane, which can activate the first C−H bond of methane to methyl species, and then react with OH − to form methanol. The good stability in cyclic operation is an additional attribute, rendering this type of catalyst a “front-runner” in future catalyst development for direct methane-to-methanol. This composite catalyst design provides hope for developing ternary metal-oxide catalysts for functionalization of methane.
研究领域:
催化化学
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环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2022
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IF 24.319
Shujuan Zhan,Huating Huang,Chun He,Ya Xiong,Ping Li,Shuanghong Tian
Nitrogen doping sites greatly affected the electronic structure of catalysts. However, identification of nitrogen doping sites in CeO 2 and their effects on catalytic ozonation have never been addressed. Herein, nitrogen was selectively doped at substitutional (N s ) or interstitial sites (N i ) in CeO 2 by simply controlling the heat treatment conditions. The obtained NCe2–400 with 100% N i significantly enhanced the elimination of sulfamethoxazole to 93.7 ± 1.9% within 30 min at the initial solution pH of 6.2. The first-order rate constant reached 8.77 × 10 −2 min −1 , 2.1 and 4.1 times that of 50.1%N s -doped CeO 2 and ozonation, respectively. The experimental and DFT calculation results demonstrate that compared to N s , N i favors the formation of oxygen vacancies (OVs). Both N i and OVs significantly decreased the energy barrier of the adsorption and activation of ozone. This study provides a simple site-tunable N-doping method and gains a new insight into the roles of N i and N s in catalytic ozonation.
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
Engineering
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2025
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IF 11.6
Ying Zhu,Jingjing Liu,Guangzhi He,Shaohua Xie,Wenpo Shan,Zhihua Lian,Fudong Liu,Hong He
Catalytic activity and hydrothermal stability are both crucial for the application of the selective catalytic reduction of NO x with NH 3 (NH 3 -SCR catalyst) in diesel vehicles. In this study, a tin (Sn)-modified Ce–Nb mixed-oxide catalyst was synthesized as an NH 3 -SCR catalyst for NO x emission control. After the introduction of Sn, both the NH 3 -SCR activity and the hydrothermal stability of the catalyst were remarkably promoted. Even after hydrothermal aging at 1000 °C, the developed Ce 1 Sn 2 Nb 1 O x catalyst achieved more than 90% NO x conversion at 325–500 °C. Various methods, including N 2 -physisorption, X-ray diffraction, in-situ high-temperature X-ray diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray absorption fine-structure spectroscopy, temperature-programmed reduction of hydrogen, temperature-programmed desorption of ammonia, and density functional theory calculations were used to investigate the promotional effects induced by the Sn species. The characterization results showed that the addition of Sn not only promoted the formation of the Ce–Nb active phase but also improved its thermal stability, contributing to the excellent NH 3 -SCR performance and hydrothermal stability. This study provides an excellent sintering-resistance catalyst for the application of diesel engine NO x emission control.
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
Nano Research
·
2021
·Vol. 15
·期 2
·1366-1374
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IF 8.897
Chen Yongdong,Li Yue,Chen Wei,Xu Wen Wu,Han Zhong-kang,Waheed Ammara,Ye Zhongbin,Li Gao,Baiker Alfons
We evaluated bismuth doped cerium oxide catalysts for the continuous synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide in the absence of a dehydrating agent. Bi x Ce 1− x O δ nanocomposites of various compositions ( x = 0.06–0.24) were coated on a ceramic honeycomb and their structural and catalytic properties were examined. The incorporation of Bi species into the CeO 2 lattice facilitated controlling of the surface population of oxygen vacancies, which is shown to play a crucial role in the mechanism of this reaction and is an important parameter for the design of ceria-based catalysts. The DMC production rate of the Bi x Ce 1− x O δ catalysts was found to be strongly enhanced with increasing O v concentration. The concentration of oxygen vacancies exhibited a maximum for Bi 0.12 Ce 0.88 O δ , which afforded the highest DMC production rate. Long-term tests showed stable activity and selectivity of this catalyst over 45 h on-stream at 140 °C and a gas-hourly space velocity of 2,880 mL·g cat −1 ·h −1 . In-situ modulation excitation diffuse reflection Fourier transform infrared spectroscopy and first-principle calculations indicate that the DMC synthesis occurs through reaction of a bidentate carbonate intermediate with the activated methoxy (−OCH 3 ) species. The activation of CO 2 to form the bidentate carbonate intermediate on the oxygen vacancy sites is identified as highest energy barrier in the reaction pathway and thus is likely the rate-determining step.
研究领域:
化学工程
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催化科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2019
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IF 14.229
Shahzad Afzal,Xie Quan,Sen Lu
Ceria based catalysts have been widely applied in ozonation of organic pollutants in wastewater treatment. Ceria with different exposed facets have not been used in catalytic ozonation. In this study, ceria nanorods (R-CeO 2 ), nanocubes (C-CeO 2 ) and nanooctahedra (O-CeO 2 ) with different exposed facets (110) + (100), (100) and (111)) respectively were used in catalytic ozonation of p-nitrophenol. Two calcination temperatures 300 and 500 °C were selected for comparative catalytic activity. Ceria nanoparticles (NP-CeO 2 ) were also prepared for comparative catalytic activity. Approximately 86%, 71%, 68%, 64%, 60% and 40% TOC was removed by ozonation catalyzed by R300-CeO 2 , C300-CeO 2 , CeO 2 -NP, O300-CeO 2 , R500-CeO 2 and ozonation alone respectively. Nanorod calcined at 500 °C (R500-CeO 2 ) showed lower catalytic activity as compared to R300-CeO 2 . O 3 was also rapidly decomposed by R300-CeO 2 as compared to other catalysts and single ozonation. Inorganic hydroxyl radical scavengers and several characterization techniques were applied for investigating the underlying mechanism of catalytic ozonation. Hydroxyl radicals, surface peroxide and surface atomic oxygen as reactive oxygen species were generated for enhancing the catalytic activity. Furthermore, irrespective of surface area, the difference in catalytic activity of ceria nanoshapes were assigned to the differences in the abundance of surface basic sites, defects densities/oxygen vacancies (OVs) and coordination number of surface atoms. This study provides an insight to use other metals with variety of exposed facets for catalytic ozonation.
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
Journal of Environmental Chemical Engineering
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2022
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IF 7.968
Nan Ma,Zhifei Hao,Guoquan Liu,He Zhang,Sihui Zhan
Acidity is a crucial factor limiting the application of ceria-based catalyst for selective catalytic reduction (SCR) of NO x with NH 3 . Unravelling the participation mechanism of acid sites on ceria-based catalyst is imperative but still lacking. Herein, by tuning the electronic interaction between MoO x and CeO 2 nanosheet with numerous pits (P-CeO 2 ) via controlling the number of surface pits of P-CeO 2 , we demonstrate that electronic interaction strongly determines the acidity properties of catalyst to modulate the catalytic performance. The MoO x /P-CeO 2 exhibits much better catalytic activity , N 2 selectivity and tolerance to SO 2 and H 2 O than MoO x /CeO 2 with few pits in a temperature range of 250–400 °C with a gas hourly space velocity (GHSV) of 60,000 h −1 , which is due to the highly dispersion of Mo-O-Mo structure over P-CeO 2 as determined by Raman. Furthermore, XPS and DFT calculations demonstrate that electrons transfer from P-CeO 2 to MoO x result in a unique dynamic transformation from Brønsted acid site to Lewis acid site, enhancing the catalytic activity. This work increases the acidity sites on the catalyst by regulating the electron oxide-support interaction, which provides a new strategy for designing highly efficient ceria-based SCR catalysts.
研究领域:
催化化学
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环境科学
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DOI
高影响因子
ACS Catalysis
·
2025
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IF 13.1
Ziyi Li,Sai Chen,Wei Wang,Jiachen Sun,Xianhui Wang,Donglong Fu,Zhi-Jian Zhao,Chunlei Pei,Jinlong Gong
The CoOx-based catalyst has attracted extensive research interest for propane dehydrogenation. However, enhancing its performance has been challenged by uncertainties surrounding the valence states of cobalt. This paper describes the pivotal role of proximity-dependent Co2+ in cobalt/ceria-based catalysts for nonoxidative propane dehydrogenation. By combining transmission electron microscopy and in situ spectroscopies, we discovered that Co2+, stabilized by the cooperative CoOx–CeOx interface, rather than metallic Co0, is responsible for activating the C–H bonds of propane. For the 1Co/20CeAl catalyst, where CoOx and CeOx are in intimate contact at the nanoscale, the highest Co2+ content was achieved, leading to the highest space–time yield (STY) of propylene with a high selectivity of 86%. Kinetic studies indicate that the proximity-dependent oxide–support interaction mediates the Co0/Co2+ ratios, resulting in a shift in the rate-determining step from the first C–H bond activation in 1Co/Al to the second C–H bond activation in 1Co/20CeAl. This study emphasizes the utilization of oxide-support interactions to optimize catalytic performance.
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
Molecular Catalysis
·
2024
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IF 3.9
Ke-Xin Li,Yongfang Jin,Weimin Huang,Decun Luo,Tao Zhang,Xiaolong Han,Yuanhao Wang,Ralph T. Yang,Zhun Hu
CeO 2 with varied doping transition metal was investigated to understand the oxygen storage capacity and oxygen release property of CeO 2 -based catalysts for toluene combustion. The order of catalytic activity was as follows: CuCeO x ≈ CoCeO x > MnCeO x > FeCeO x > NiCeO x > ZrCeO x > CeO 2 . Kinetic studies showed that the reaction on CuCeO x proceed via an MvK mechanism and the oxygen of catalyst was crucial factor for the toluene combustion. H 2 -TPR and XPS showed the addition of transition metal to CeO 2 could modify the surface lattice oxygen. Moreover, the oxygen storage capacity and oxygen release properties showed the transition metal additive not only change the amount of oxygen, but also affect the oxygen mobility. A linear relationship was observed between the catalytic activity and oxygen storage capacity. Diffuse reflectance infrared fourier transform spectroscopy showed the toluene first adsorbed on the surface of catalyst, and then reacted with oxygen of catalyst to form benzyl, benzoate and benzyl carbonate species. All these results provided a new strategy to develop high performance catalyst.
研究领域:
催化化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
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2021
·
IF 7.92
Jiawei Ji,Meizan Jing,Xiuwen Wang,Wei Tan,Kai Guo,Lulu Li,Xin Wang,Wang Song,Lijun Cheng,Jingfang Sun,Weiyu Song,Changjin Tang,Jian Liu,Lin Dong
The occurrence of NH 3 -SCR (selective catalytic reduction of NO with NH 3 ) reaction on catalyst surface typically requires acid and redox sites. However, the role of acid-redox interaction on NH 3 -SCR performance is still obscure due to complex acidities and entangled acid-redox sites. Herein, three types of model Ce 2 (SO 4 ) 3 -CeO 2 catalysts with distinct interfaces are constructed to reveal the effect of acid-redox interaction on NH 3 -SCR performance. That is, SO 4 2- /CeO 2 -VS (vapor sulfation of ceria) with strong acid-redox interfacial contact, SO 4 2- /CeO 2 -WI (wet impregnation), and SO 4 2- /CeO 2 -SG (solid grinding) with limited interfaces. It is found the redox property is significantly disturbed as a result of the electron-withdrawing effect from the sulfate. Theoretical result unravels that the introduction of Ce 2 (SO 4 ) 3 retards the oxygen vacancy formation over CeO 2 . Due to restricted interfaces in SO 4 2- /CeO 2 -SG, the negative influence from acid sites is greatly alleviated. Further mechanism study discloses the weakened acid-redox interaction actually changes the nature of surface NO x species, resulting in the generation of reactive species (*O-N-O* and cis -N 2 O 2 2- ) and the promotion of surface reaction via Langmuir-Hinshelwood (L-H) mechanism.
研究领域:
催化化学
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环境科学
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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）