ChemCatChem
·
2021
·Vol. 13
·期 15
·3490-3500
·
IF 5.686
Mingwei Wu,Wenzhi Li,Xia Zhang,Fengyang Xue,Tao Yang,Liang Yuan
Graphical Methane combustion : Defect-Rich CeO 2 −Al 2 O 3 supported palladium catalysts can prominently improve the dispersion of palladium species and strengthen the concentration of active surface oxygen species, resulting in excellent catalytic activity for methane combustion. In heterogeneous catalysis, the strong interaction between metal and support can significantly modulate the electronic properties of the metals and play a crucial role in metal particle dispersion and morphology. Herein, a facile strategy was utilized to fabricate highly dispersive palladium catalysts supported on defective Al 2 O 3 −CeO 2 for lean methane oxidation. Ceria was immobilized on the coordinatively unsaturated Al 3+ penta sites of γ-alumina activated by pre-reduction to fabricate hybrid-oxide support (abbreviated as RAl 2 O 3 −CeO 2 ), and then Pd precursor was uniformly deposited on the defective surface. Such a RAl 2 O 3 −CeO 2 interface can effectively upgrade the dispersion of deposited palladium species and improve the concentration of reactive oxygen species owing to strong electronic interactions, invoking a superior catalytic activity for lean methane oxidation. After loading 1.0 wt% palladium, Pd/RAl 2 O 3 −CeO 2 exhibited a 90 % methane conversion at 328 °C under the space velocity of 60,000 mL g −1 h −1 , far lower than that of bare 1.0 wt% Pd/RAl 2 O 3 (400 °C). In addition, Pd/RAl 2 O 3 −CeO 2 catalyst showed an excellent hydrothermal stability under the harsh conditions (600 °C, water vapor)for 120 h without obvious deactivation. The reaction pathway of total methane combustion was elucidated by in situ DRIFTS. The crucial intermediate compositions (carbon oxygenates and carbonate)on Pd/RAl 2 O 3 −CeO 2 surface are more readily oxidized into CO 2 and H 2 O. This work provides an effective interface-promoted strategy to develop efficient and durable palladium catalysts for many challenging reactions.
研究领域:
催化化学
·
材料科学
·
环境工程
✓ 已验证
DOI
高影响因子
Applied Nanoscience
·
2021
·Vol. 11
·期 10
·2549-2560
·
IF 3.674
Dai Xiusong,Wang Xiaopan,Chen Xiaotian,Ye Longfei,Wu Min
In this work, two Gram-negative and three Gram-positive pathogenic pathogens were examined for the antibacterial activity of cerium oxide nanoparticles. CeO 2 nanoparticles (CeO 2 NPs) encapsulation with hydroxyapatite and chitosan were synthesised using the precipitation procedure and simultaneous reactant addition by techniques of a Wet Chemical Synthesis approach. Thermal analyses (TG–DTA), their degradation processes and their synthesis of CeO 2 NPs were investigated, and the precursor powders were acquired. Fourier transform infrared (FTIR), X-ray diffraction, Raman spectroscopy, transmission electron microscopy (TEM), and dynamic light scattering (DLS) examined the thermally treated sample’s composition, structure, and morphology. CeO 2 NPs antioxidant has also been determined. The analysis against five diseased pathogens, including Bacillus cereus, Staphylococcus aureus , Listeria monocytogenes , Salmonella typhimurium and Escherichia coli , has been performed on both fluid growth mediums. The growth inhibition of cerium oxide nanoparticles in all five pathogens studied exhibited noteworthy results. This study underlines the CeO 2 NPs, which revealed considerable changes in antibacterial activity because of the changes in membrane structure and the composition of cell walls across the two test groups. As a result, generated CeO 2 NPs can be prospective osteomyelitis therapy candidates.
研究领域:
医学
·
材料科学
·
微生物学
✓ 已验证
DOI
高影响因子
Catalysts
·
2022
·Vol. 12
·期 9
·1034
·
IF 4.501
Ahmed Ismail,Muhammad Zahid,Boren Hu,Adnan Khan,Nauman Ali,Yujun Zhu
Catalytic oxidation is regarded as an effective, economical, and practical approach to remove volatile organic compounds such as important air pollutants. CeO2catalysts with different morphologies exhibit different oxygen vacancies content, which plays a vital role in oxidation reaction. Herein, three distinct morphologies of CeO2i.e., shuttle (CeO2(S)), nanorod (CeO2(R)), and nanoparticle (CeO2(P)), were successfully fabricated by the SEM and TEM results, and investigated for toluene catalytic oxidation. The various characterizations showed that the CeO2(S) catalyst exhibited a larger surface area along with higher surface oxygen vacancies in contrast to CeO2(R) and CeO2(P), which is responsible for its excellent toluene catalytic oxidation. The 90% toluene conversion temperature at 225 °C over CeO2(S) was less than that over CeO2(R) (283 °C) and CeO2(P) (360 °C). In addition, CeO2(S) showed a greater reaction rate (14.37 × 10−2μmol∙g−1∙s−1), TOFov(4.8 × 10−4∙s−1) at 190 °C and lower activation energy value (67.4 kJ/mol). Furthermore, the CeO2(S) also displayed good recyclability, long-term activity stability, and good tolerance to water. As a result, CeO2(S) is considered a good candidate to remove toluene.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
POLYMER BULLETIN
·
2021
·Vol. 79
·期 3
·1751-1765
·
IF 2.87
Sun Yiwen,Zhai Guangqun
Since cerium(IV) ammonium nitrate (CAN) could oxidize amidyl N–H moieties into nitrogen-centered radicals under proper conditions to initiate radical polymerization, CAN-acrylamide (AAm) redox-initiated radical homo/co-polymerization in a conventional or controlled manner was exploited with AAm as an intrinsically reducing inimer. CAN oxidized AAm to initiate conventional radical homopolymerization at 50–60 °C, and viscosity-average molecular weight (MW) of polyacrylamide (PAAm) steadily increased with conversion because of the oxidation of amidyl N–H moieties of in-chain -AAm- units, but MW was in a range from 10 4 to 10 5 . CAN-AAm redox-initiated radical co-polymerization of N,N -dimethylacrylamide (DMAAm) proceeded readily under optimized conditions and formed PAAm-co-PDMAAm with MW in a range from 10 5 to 10 6 , and increasing simultaneously with conversion. CAN-AAm redox-initiated controlled radical homopolymerization was performed with FeCl 3 complexes as the deactivator, and the polymerization proceeded in a mechanism of reverse atom transfer radical polymerization (ATRP) and MW of PAAm increased in proportion to conversion. The PAAm chains contained a C–Cl terminal, which was confirmed by block co-polymerization with DMAAm via standard ATRP with PAAm as the macro-initiator.
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2018
·
IF 3.956
Shu-Sen Liu,Yong-Yong Jin,Yahong Han,Jinxian Zhao,Jun Ren
It is a big challenge to improve the stability and anti-coking abilities of catalyst in high temperature CO methanation reaction. To address the issue, SiC was chose as the support, and Ce was used as a promoter to prepare supported Ni catalysts for CO methanation. A long-term high temperature stability evaluation experiment was carried out at 600 °C for 100 h in comparison with Ni/Al 2 O 3 catalyst. The catalysts were characterized by a combination of characterization techniques for understanding the catalytic performance and carbon deposition behaviors in CO methanation. The life test result indicates that, compared to Ni/Al 2 O 3 , Ni/SiC is thermally stable and highly resistant to carbon deposition . Improved cataytic activity and stability was further reached by introduce of Ce promoter into Ni/SiC, which can be attributed to the enhanced interaction between Ni and SiC and improved dispersion of Ni active species.
研究领域:
催化化学
·
能源化学工程
·
材料科学
·
工业催化
·
化学反应工程
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Meiqi Gao,Junhao Ma,Yanyan Li,Ximao Lin,Limin Wu,Yidong Zou,Yonghui Deng
Hydrogen generation is one of the crucial technologies to realize sustainable energy development, and the design of advanced catalysts with efficient interfacial sites and fast mass transfer is significant for hydrogen evolution. Herein, an in situ coassembly strategy was proposed to engineer a cerium-doped ordered mesoporous titanium oxide (mpCe/TiO2), of which the abundant oxygen vacancies (Ov) and highly exposed active pore walls contribute to good stability of ultrasmall Pt nanoclusters (NCs, ∼ 1.0 nm in diameter) anchored in the uniform mesopores (ca. 20 nm). Consequently, the tailored mpCe/TiO2 with 0.5 mol % Ce-doping-supported Pt NCs (Pt-mpCe/TiO2-0.5) exhibits superior H2 evolution performance toward the water–gas shift reaction with a 0.73 molH2·s–1·molPt–1 H2 evolution rate at 200 °C, which is almost 6-fold higher than the Pt-mpTiO2 (0.13 molH2·s–1·molPt–1 H2). Density functional theory calculations confirm that the structure of Ce-doped TiO2 with Ce coordinated to six O atoms by substituting Ti atoms is thermodynamically favorable without the deformation of Ti–O bonds. The Ov generated by the six O atom-coordinated Ce doping is highly active for H2O dissociation with an energy barrier of 2.18 eV, which is obviously lower than the 2.37 eV for the control TiO2. In comparison with TiO2, the resultant Ce/TiO2 support acts as a superior electron acceptor for Pt NCs and causes electron deficiency at the Pt/support interface with a 0.17 eV downshift of the Pt d-band center, showing extremely obvious electronic metal–support interaction (EMSI). As a result, abundant and hyperactive Ti3+-Ov(-Ce3+)-Ptδ+ interfacial sites are formed to significantly promote the generation of CO2 and H2 evolution. In addition, the stronger EMSI between Pt NCs and mpCe/TiO2-0.5 than that between Pt and mpTiO2 contributes to the superior self-enhanced catalytic performance during the cyclic test, where the CO conversion at 200 °C increases from 72% for the fresh catalyst to 99% for the used one. These findings reveal the subtle relationship between the mesoporous metal oxide-metal composite catalysts with unique chemical microenvironments and their catalytic performance, which is expected to inspire the design of efficient heterogeneous catalysts.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Kang Wu,Yuhai Sun,Jing Liu,Juxia Xiong,Junliang Wu,Jin Zhang,Mingli Fu,Limin Chen,Haomin Huang,Daiqi Ye
The insights on the primary surface-reactive oxygen species and their relation with lattice defects is essential for designing catalysts for plasma-catalytic reactions. Herein, a series of Ba 1−x Ce x TiO 3 perovskite catalysts with high specific surface areas (68.6–85.6 m 2 g −1 ) were prepared by a facile in-situ Ce-doping strategy and investigated to catalytically decompose toluene. Combining the catalysts with a nonthermal plasma produced a significant synergy effect . The highest decomposition efficiency (100%), CO x selectivity (98.1%), CO 2 selectivity (63.9%), and the lowest O 3 production (0 ppm) were obtained when BC 4 T (Ce/Ti molar ratio = 4:100) was packed in a coaxial dielectric barrier discharge reactor at a specific input energy of 508.8 J L −1 . The H 2 -TPR, temperature-programmed Raman spectra , EPR and OSC results suggested that superoxides ( • O 2 − ) were the primary reactive oxygen species and were reversibly generated on the perovskite surface. Molecular O 2 was adsorbed and activated at the active sites (Ti 3+ -V O ) via an electron transfer process to form • O 2 − . Surface-adsorbed • O 2 − had a greater effect on the heterogeneous surface plasma reactions than the dielectric constant , and enhanced the toluene decomposition and intermediate oxidation . A possible reaction path of toluene decomposition was also proposed.
研究领域:
环境科学
·
催化材料
·
等离子体化学
✓ 已验证
DOI
高影响因子
Journal of Energy Storage
·
2022
·
IF 8.907
Zhiguo Bian,Yingjie Li,Feifei Wang,Yi Fang,Jianli Zhao,Jianhui Qi
CaO/Ca(OH) 2 heat storage system is one of the most promising candidates for large-scale thermochemical heat storage at temperature of 300–600 °C. In this work, the CaO/Ca(OH) 2 heat storage performances of the Ce- and Mn-doped CaO were investigated and the mechanisms of promoting hydration by Ce and Mn doping were determined via density functional theory (DFT) calculations. The Mn-doped CaO exhibits the higher hydration conversion than CaO and Ce-doped CaO. The structural parameters, partial density of states, electron differential densities and energy barriers during hydration stage on the CaO, Ce- and Mn-doped CaO surfaces were compared to clarify the effects of Ce and Mn on hydration of CaO. The results show the detailed hydration reaction pathways on the CaO, Ce- and Mn-doped CaO surfaces. During the H 2 O adsorption stage, H 2 O on the Ce-doped CaO surface approaches the Ca atom first, while H 2 O on the Mn-doped CaO surface approaches the O s atom first. The adsorption energy for Ce- and Mn-doped CaO are −1.612 and −0.896 eV, respectively, which are higher than that for CaO. The doping of Ce and Mn accelerates the H 2 O adsorption on the CaO surface. The Mn doping causes the 84.3 % reduction in the energy barrier for hydration of CaO and the reduction by Mn doping is larger than that by Ce doping. Thus, Mn-doped CaO exhibits the higher hydration reactivity and hydration conversion than CaO and Ce-doped CaO. The DFT calculations determined the promotion mechanism of Ce and Mn doping on the hydration of CaO in CaO/Ca(OH) 2 heat storage.
研究领域:
材料科学
·
热能储存
·
计算化学
✓ 已验证
DOI
高影响因子
MATERIALS SCIENCE-POLAND
·
2024
·Vol. 42
·期 1
·158-170
·
IF 1.3
Yilin Li,Yonggang Liu,Wei Hao,Zhaogang Liu,Wentao Zhang,Yanhong Hu,Jinxiu Wu
Enhancing the service life of natural rubber (NR) products, including antioxidants, is crucial to prevent rubber degradation and enhance its oxidation resistance. Phenolic antioxidant 2246 and cerium complex of p-amino salicylic acid (PAS-Ce) are utilized as NR antioxidants. Numerous studies have qualitatively analyzed the antioxidant mechanisms of these compounds. Building upon this perspective, this study quantitatively assessed the protective mechanisms of these antioxidants by combining experimental data with molecular simulations. Additionally, it compared their impacts on the thermal oxidative aging performance of NR. The findings revealed that the PAS-Ce/NR system exhibited the highest mechanical performance retention following multiple days of thermal-oxidative aging. Analyzing the PAS-Ce/NR system through ATR-FTIR and DTA techniques demonstrated that it had the lowest C=O content after thermal-oxidative aging. Furthermore, calculating the activation energy required for thermal-oxidative aging decomposition using the Kissinger and FWO methods indicated that PAS-Ce/NR had the highest activation energy, suggesting superior inhibitory effects against thermal-oxidative aging. Quantum mechanical simulations also illustrated that the dissociation energy of the O-H bond in antioxidants 2246 and PAS-Ce was lower than that of the C-H bond in NR. However, PAS-Ce exhibited a quicker capture of radical species, effectively delaying the oxidation reaction rate of NR molecular chains and thus more efficiently inhibiting the aging process. These insights contribute significantly to comprehending the antioxidative mechanisms in NR aging.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Science China-Chemistry
·
2024
·
IF 10.4
Kimaka P. Rinel R.,Wang Ping,He Miao,Meng Senyao,Yao Jiasai,Li Huawei,Yang Cheng,Li Zhenxing
Polymetallic layered double hydroxides are promising cost-effective catalysts for the oxygen evolution reaction (OER) due to their versatile anionic and cationic tunability. Nevertheless, several challenges persist, notably, issues related to low electrical conductivity, poor catalytic activity, and stability, especially at high current density. Herein, we report the design of Ce- and La-doped CoNiFe-layered double hydroxide (CeLaCoNiFe-LDH) nanosheets through a facile and scalable in situ self-assembly strategy that displays enhanced OER activity. Experimental and theoretical investigations provide insights into the impact of Ce-and La-doping by comparing CeCoNiFe-LDH, LaCoNiFe-LDH, and pristine CoNiFe-LDH, all synthesized using the same methodology. These results reveal that doping Ce 3+ and La 3+ into CoNiFe-LDH substantially improves its electronic structure, resulting in enhanced conductivity, more oxygen vacancies (Vo), electron interaction, and active site formation. Consequently, significantly reduced overpotentials of 175, 314, and 424 mV at 10, 100, and 500 mA cm −2 , respectively, and a highly stable current density of 120 h in 1 M KOH were achieved. Notably, these performance metrics surpass those of unmodified LDHs and are competitive with many lanthanide-doped transition metal-based LDH electrocatalysts, as well as noble metal catalysts like ruthenium catalysts. This work represents a pioneering effort in doping Ce 3+ and La 3+ ions into a functional CoNiFe-based electrocatalyst, offering inspiring OER performance and scalability potential.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Ning Kang,Zhiqiang Zhao,Xiaoyang Yu,Jin Lin,Shouxiang Lu
The application of ceria-supported catalysts as promising catalysts for air pollutant abatement via heterogeneous catalytic processes is still a challenge. Phosphorus (P) is a potential threat to catalyst deactivation but has not been sufficiently explored. Herein, a systematic study reveals the poisoning behaviors of P on Cu-Mn bimetallic oxides supported by ceria (Cu-Mn/CeO 2 ) as a typical case in CO oxidation and provides new insights into the deactivation mechanism. The P impregnation decreases the surface area of Cu-Mn/CeO 2 and leads to the emergence of a new sheet morphology. The interactions between P and catalyst components (support and active species) result in the generation of dominant P species of PO 4 3− and PO 3 − . The P addition also weakens the oxygen storage capacity of ceria and decreases the proportions of low-valent Cu and Mn, hindering electron transfers among metals. Furthermore, the reducibility and the adsorption and activation of O 2 are limited in P-loaded Cu-Mn/CeO 2 catalysts as found in H 2 -TPR and O 2 -TPD when increasing the P concentration. In situ DRIFTS experiments demonstrate that the inhibition of the formation and transformation of active intermediates, namely carbonyls and carbonates, is responsible for the poisoning behaviors of P in the pathway of CO oxidation over Cu-Mn/CeO 2 catalyst.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
Nature Communications
·
2024
·Vol. 15
·期 1
·1-9
·
IF 14.7
Shao Weipeng,Zhang Yi,Zhou Zhiwen,Li Na,Jiao Feng,Ling Yunjian,Li Yangsheng,Zhou Zeyu,Cao Yunjun,Liu Zhi,Pan Xiulian,Fu Qiang,Wöll Christof,Liu Ping,Bao Xinhe,Yang Fan
Ceria (CeO 2 ) is a widely used oxide catalyst, yet the nature of its active sites remains elusive. This study combines model and powder catalyst studies to elucidate the structure-activity relationships in ceria-catalyzed CO activation and hydrogenation. Well-defined ceria clusters are synthesized on planar CeO 2 (111) and exhibit dynamic and tunable ranges of Ce coordination numbers, which enhance their interaction with CO. Reduced ceria clusters (e.g., Ce 3 O 3 ) bind CO strongly and facilitate its dissociation, while near-stoichiometric clusters (e.g., Ce 3 O 7 ) adsorb CO weakly and promote oxidation via carbonate formation. Unlike planar ceria surfaces, supported ceria clusters exhibit dynamic properties and enhanced catalytic activity, that mimic those of powder ceria catalysts. Insight from model studies provide a method to quantify active sites on powder ceria and guide further optimization of ceria catalysts for syngas conversion. This work marks a leap toward model-guided catalyst design and highlights the importance of site-specific catalysis.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）