HELVETICA CHIMICA ACTA
·
2023
·Vol. 106
·期 5
·e202200203
·
IF 1.8
Peng Liu,Xin Zhang,Yuan-Yuan Huang,Geng-Wei Liu,Chen-Jie Li,Pin-Mei Yan,Ye-Yan Qin,Rong Guo,Si-Qi Wu,Yun-Yun Zeng,Peng-Bin Pan,Yuan-Gen Yao
High active Pd-based catalyst with low loading capacity for CO oxidative coupling with methyl nitrite (MN) to dimethyl oxalate (DMO) has aroused great interest in the large-scale production of DMO for the next hydrogenation to bring forth ethylene glycol (EG). Here, spinel composite oxide support, namely MgAl 2 O 4 , had been prepared through three different methods: solid combustion method (MAO-SC), hydrothermal method (MAO-HT) and co-precipitation method (MAO-CP), and further Pd nanoparticles were anchored to the surface of MgAl 2 O 4 through a simple wetness impregnation method. In the CO direct esterification to DMO reaction, the Pd/MAO-SC catalyst, which used MgAl 2 O 4 support prepared by solid combustion method, exhibited the highest intrinsic activity with Turnover frequency (TOF) value of 2.39 s −1 and DMO weight space-time yield (956.8 g⋅kg cat −1 ⋅h −1 ) with 44.1 % CO conversion and 97.8 % DMO selectivity, and showed negligible attenuation of activity during the process of continuous reaction for 100 h. The characterization results confirmed that abundant oxygen defect sites occurred in MAO-SC synthesized by combustion method not only can help to anchor the Pd nanoparticles with appropriate size and dispersion, but also can promote the interfacial electron transfer from MgAl 2 O 4 support to Pd nanoparticles, thus significantly enhancing the metal-support interaction (MSI) and providing more CO bridge-adsorption sites that is favorable for the CO oxidative coupling with MN to DMO reaction.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
BIOMASS & BIOENERGY
·
2025
·
IF 5.8
Zhaojie Qin,Dongmei Bi,Bozheng Li,Xiang Zhu,Yu Ni,Lihong Wang
Furfural (FF) is a platform chemical with high value and wide application. The catalysts (Zinc oxide modified magnesium-aluminum spinel catalyst (Zn/MgAl 2 O 4 )) prepared in this paper allowed for the fast and efficient preparation of FF. Catalytic pyrolysis experiments were carried out on three typical biomass, and it was found that Zn/MgAl 2 O 4 had a significant enrichment effect on the production of FF in bio-oil. And the effect was more pronounced in the camphor wood experiments. Under pyrolysis conditions (400 °C, catalyst to biomass mass ratio is 1:1), FF relative content reached 64.31 wt%. Zn 2+ increased the acidic sites in Zn/MgAl 2 O 4 and accelerates proton transfer. Glycosidic bond cleavage and monomer degradation were significantly enhanced, resulting in improved FF conversion efficiency. The relative content of FF in the bio-oils obtained from pyrolysis of the three biomass feedstock in the temperature range of 400–600 °C was more than 50 wt%, and the results were better at low temperatures. The results of this paper can provide a theoretical basis for the preparation of FF from clean energy biomass.
研究领域:
能源生物学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2021
·
IF 5.816
Yu Qiu,Enkang Fu,Feng Gong,Rui Xiao
Ammonia is a prospective fuel for hydrogen storage and production, but its application is limited by the high cost of the catalysts (Ru, etc. ) to decompose NH 3 . Decomposing ammonia using non-precious Ni as catalysts can therefore improve its prospects to produce hydrogen. This work proposes several Ni/MgAl 2 O 4 with the support properties tuned and investigates the support effect on the catalytic performance. Ni/MgAl 2 O 4 -LDH shows high NH 3 conversion (∼88.7%) and H 2 production rate (∼1782.6 mmol g −1 h −1 ) at 30,000 L. kg −1 h −1 and 600 °C, which is 1.68 times as large as that of Ni/MgAl 2 O 4 -MM. The performance remains stable over 30 h. The characterizations manifest that the high specific surface area of Ni/MgAl 2 O 4 -LDH can introduce highly dispersed Ni on the surface. Kinetics analysis implies promoted NH 3 decomposition reaction and alleviated H 2 poisoning for Ni/MgAl 2 O 4 -LDH. A roughly linear relationship is obtained by fitting the curves of dispersed Ni on the surface vs the reaction orders regarding H 2 and NH 3 . This indicates that enhanced NH 3 decomposition performance can be ascribed to the strengthened NH 3 decomposition reaction and weakened H 2 poisoning by the highly dispersed Ni on the MgAl 2 O 4 -LDH surface. This work provides an opportunity to develop highly active and cost-effective catalysts to produce hydrogen via NH 3 decomposition.
研究领域:
化学工程
·
能源科学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2021
·
IF 19.503
Yongxiao Tuo,Ying Meng,Chen Chen,Dong Lin,Xiang Feng,Yuan Pan,Ping Li,De Chen,Zhanning Liu,Yan Zhou,Jun Zhang
Platinum group metals hold pronounced potential for the dehydrogenation process of liquid organic hydrogen carriers (LOHCs) such as decalin, but the strong adsorption of dehydrogenation product has suppressed the moving forward of these catalysts. Herein, we described that the strong interactions between Pt and MgAl 2 O 4 trigger partial positively charged Pt, which mitigates the adsorption of naphthalene on highly active Pt sites, thus achieving an outstanding decalin dehydrogenation activity that is nearly twice that of state-of-the-art Pt/CNF catalysts. As revealed by various characterization outcomes and DFT calculations, the strong electronic interactions between Pt and spinel oxygen surface resulted in partial positively charged Pt on MgAl 2 O 4 , which inhibits the electron transfer from Pt to unsaturated carbon of naphthalene, thus weakening the bond strength between Pt and naphthalene. As a result, the combination of small-sized Pt nanoparticles and facile desorption of products endows tremendous dehydrogenation activity of Pt/MgAl 2 O 4 . This study may shed new light on the rational construction of highly efficient metal catalysts for the application of LOHCs.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2020
·Vol. 49
·期 11
·3606-3614
·
IF 4.174
Yibing Wu,Yixi Zhuang,Rong-Jun Xie,Kaibin Ruan,Xinhua Ouyang
Red emitters based on CaAl12O19:Mn4+ have been attracting extensive attention due to their advantages of being rare-earth-free and chemically stable. However, their relatively low luminescence efficiencies will seriously hinder their application in light-emitting diodes (LEDs). In this regard, the promising red phosphors of CaAl12O19:Mn4+ were synthesized with enhanced luminous efficiency by introducing the coexisting phase of MgAl2O4. Importantly, an approximately 5 times enhancement of integrated intensity in the emission spectrum was observed for the phosphor with the coexisting phase compared to that with a single phase. Their crystal structures, morphologies and photoluminescence properties and the mechanism of improved luminescence were systematically investigated. Upon exciting them by using near-ultraviolet or blue LEDs, an efficient red emission was achieved with a maximum peak at ∼658 nm. In order to evaluate their potential application, a warm white LED and a plant growth LED were fabricated by using the prepared phosphors in combination with YAG:Ce3+ and InGaN-based blue chips.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF FLUORESCENCE
·
2024
·
IF 2.6
Zha Jiahao,He Chongjun,Chen Fangzhou,Wang Hongwei,Dong Biao,Liu Lijuan,Xia Mingjun,Deng Chenguang,Li Qian,Lu Yuangang,Chen Huiting
Oxide matrix red-emitting phosphors are deemed as excellent color converters for white light emitting diodes (WLEDs) and laser diodes (LDs). Manganese-doped MgAl 2 O 4 powder was synthesized by a solid-state reaction method at different sintering temperatures. Microstructure shows that grain size is mainly in the range of 0.2–5 μm, and grain agglomeration occurs with increased sintering temperature. XPS analysis indicates that the doped Mn ion exhibits a valence state of + 4 within the MgAl 2 O 4 matrix. The diffraction peak of the phosphors is shifted by the sintering temperature, which affects lattice constant. Upon excitation by 300 nm ultraviolet light, the samples emit asymmetric broadband red light within the range of 620–720 nm, attributed to Mn 4+ ion’s transition from 2 E g to 4 A 2g states. With the increasing temperature, the main emission peak shifts from 677 nm to 650 nm, ascribed to the change in energy level ( 2 E g ) resulting from the reduction of Al 2 O 3 phase. Crystal field theory confirmed that Mn 4+ ions are within a strong crystal field environment created by MgAl 2 O 4 matrix. By affecting particle size and crystallinity, the sintering temperature influences the fluorescence lifetime of the Mn 4+ ion. Notably, these red-emitting phosphors exhibits remarkable thermal stability as their emission intensity remains approximately at 58% of initial intensity even at elevated temperature (435 K). Consequently, Mn 4+ : MgAl 2 O 4 red-emitting phosphors with high thermal stability render them promising candidates for WLED applications.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
CHEMICAL PHYSICS LETTERS
·
2021
·
IF 2.328
Qian Wu,Guo Feng,Lifeng Miao,Zijuan Tang,Weihui Jiang,Jian Liang,Jianmin Liu
Mesoporous petal-like MgAl 2 O 4 spinel has been prepared by molten salt assisted nonhydrolytic sol–gel method. The influence of Mg/Al molar ratio (0.45, 0.50, 0.55, 0.60, 0.70 and 0.80) on the morphology and surface area of MgAl 2 O 4 was investigated. The results reveal that Mg/Al molar ratio has a significant influence on the morphology. At Mg/Al molar ratio of 0.7, the achieved petal-like MgAl 2 O 4 is highly uniformed in morphology, the surface area and pore volume reached maximum values of 141 m 2 g −1 and 0.24 cm 3 g −1 , respectively. These properties make it have promising applications in the catalyst support field.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY
·
2020
·
IF 4.825
Zhaowu Wang,Haipeng Ji,Jian Xu,Xinghui Hou,Jumpei Ueda,Setsuhisa Tanabe,Shasha Yi,Ying Zhou,Deliang Chen
A single-crystalline defect-less phosphor is desired for efficient luminescence of the therein doped optical activators. In this paper, microsized MgAl2O4:Mn4+ single-crystal phosphors with bright red luminescence were grown in molten LiCl salt at 950 °C, for application in blue LED pumped white lighting. By comparing the phosphor formation from various Mg2+- and Al3+-bearing sources, both the template-formation and the dissolution-diffusion processes were evidenced to account for the formation of the microsized MgAl2O4:Mn4+ crystallites. Using nano γ-Al2O3 as the Al3+-bearing precursor, the uniform MgAl2O4:Mn4+ microcrystallites with a {111} planes-exposed tetragonal bipyramid morphology were obtained. The photoluminescence property was studied at various temperatures, and Mg ↔ Al anti-site disorder induced luminescence broadening was discussed. The Mn4+2Eg → 4A2g transition in MgAl2O4 shows a quite short luminescence wavelength peaking at 651 nm and ultrabroadband emission extending to 850 nm. The luminescence is relatively robust against thermal effect with relatively high thermal quenching temperature of 400 K and activation energy of 0.23 eV. Employing the red-emitting MgAl2O4:Mn4+ crystallites, blue LED pumped white lighting prototypes were fabricated which simulate the solar-like spectrum and show neutral to warm white.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Fucheng Wang,Jiajun Li,Chunsheng Shi,Enzuo Liu,Chunnian He,Naiqin Zhao
Ceramic phase reinforced aluminum matrix composites (CAMCs) are widely used in high-tech fields represented by aerospace industry due to their advantages of high specific strength, high specific modulus, high thermal stability, and light weight. Strong interface bonding is a prerequisite for high performance of multiphase materials. Herein, a novel CAMC in situ reinforced by MgAl2O4 particles and MgAlB4 nanorods was prepared by vacuum hot-pressing combined with hot-extrusion process. A high-resolution transmission electron microscope was used to characterize the orientation relationship and interface structure between the ceramic phases and the aluminum matrix. Two orientation relationships (OR1 and OR2) of MgAl2O4/Al and one (OR3) of MgAlB4/Al are determined: OR1-[011]p//[011]Al, (11̅1)p//(11̅1)Al; OR2-[211]p//[011]Al, (113̅)p//(022̅)Al; OR3-[101̅0]R//[001]Al, (0002)R//(2̅20)Al. The MgAl2O4 in OR1 forms a coherent interface with the aluminum matrix at (111) surface, while they form a 4 × 5 near coincidence site lattice (CSL) interface structure for OR2. In OR3, the MgAlB4 forms an approximate coherent interface with Al matrix at its (0002) surface and a 2 × 5 CSL interface structure at its (011̅0) surface. First-principles calculations suggest that MgAl2O4 combines to aluminum at (111) plane through covalent bonds, which means high interfacial bonding strength. The hot-extrusion process makes the ceramic phase evenly distributed in the matrix. The mechanical properties of the composites are greatly improved compared with pure aluminum.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advanced Energy and Sustainability Research
·
2024
·Vol. 5
·期 8
·2400044
·
IF 6.2
Jie Li,Jieying Cai,Yan Zhang,Peng Wang,Xuehai Wang,Xiangchen Fang,Yunbo Yu,Wenpo Shan
Mesoporous MgAl 2 O 4 is synthesized via a novel sol–gel combustion method and the concentration of oxygen defects on the surface is modulated through varying the calcination temperature (850, 900, 1000, and 1100 °C). Notably, the 1Pd/MgAl 2 O 4 -1000 catalyst exhibits superior catalytic activity and stability. The turnover frequency (TOF) for 1Pd/MgAl 2 O 4 -1000 is 0.079 and 0.058 s −1 under dry conditions (300 °C) and wet conditions (380 °C), respectively. The results of H 2 temperature-programmed reduction and X-Ray photoelectron spectroscopy reveal that the principal active species within the Pd/MgAl 2 O 4 -y catalyst is PdO. Specifically, the Pd–MgAl 2 O 4 -1000 catalyst exhibits the lowest temperature reduction peak (120 °C) and the highest redox capability. Additionally, O 2 temperature-programmed oxidation further elucidates that PdO x species in the Pd/MgAl 2 O 4 -1000 catalyst is prone to decomposition and the resultant palladium metal is readily reoxidized. Consequently, the rapidity of the redox cycle between PdO and Pd 0 emerges as a pivotal factor in CH 4 catalytic combustion. Furthermore, a correlation analysis among catalyst particle size, oxygen defect concentration, and TOF is conducted. The findings illustrate a distinct volcano-shaped curve in the relationship between oxygen defect concentration and TOF for the 1Pd/MgAl 2 O 4 −y catalysts. A comparable trend is also evident in the correlation between Pd particle size and TOF.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
·
2024
·
IF 4.3
Qian Wu,Guo Feng,Feng Jiang,Xiaojun Zhang,Yanqiao Xu,Jianmin Liu,Jian Liang,Xinbin Lao,Zhiqi Guo
This paper reports a facile treatment to enhance the capacity of petal-like MgAl 2 O 4 for Congo red (CR) adsorption. The influence of dehydroxylation treatment on the adsorption performance of petal-like MgAl 2 O 4 is investigated. FT-IR, XPS, TG, XRD and FE-SEM are employed to analyze the differences between samples without and with dehydroxylation. Mechanism on the adsorption capacity improvement of CR by MgAl 2 O 4 after dehydroxylation is investigated systematically. Results show that the adsorption process conforms well to the pseudo-second-order kinetic model and Langmuir isotherm model. The adsorption mechanism study shows that the adsorption of CR on petal-like MgAl 2 O 4 is mainly due to chemisorption including Lewis acid-base interaction and electrostatic attraction. It is observed that the maximum adsorption capacity of petal-like MgAl 2 O 4 after dehydroxylation reaches 3264.54 mg/g, much higher than sample without dehydroxylation (591.72 mg/g). Most Lewis acid sites of petal-like MgAl 2 O 4 (Mg 2+ and Al 3+ ) without dehydroxylation process are occupied by hydroxyl groups. It is not conductive to combine with –NH 2 and –SO 3 2- in CR molecular, resulting in the deterioration of adsorption performance. The activity of Mg 2+ and Al 3+ in MgAl 2 O 4 can be recovered greatly after the removal of hydroxyl groups, and it is favorable to the adsorption between MgAl 2 O 4 and CR.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Jie Li,Yan Zhang,Wenpo Shan,Hong He
A series of mesoporous Pd/Al 2 O 3 and Pd/MgAl 2 O 4 catalysts with different palladium contents (0.5, 1 and 4 wt%) were prepared by the impregnation method and used for methane combustion. Among the catalysts studied, 1Pd/MgAl 2 O 4 (1 wt% Pd) was found to be highly effective for the catalysis of CH 4 combustion below 450 °C, with a low apparent activation energy of ∼50.1 kJ/mol, and had good thermal stability. The characterization results showed that the excellent catalytic performance of Pd/MgAl 2 O 4 can be ascribed to the strong interaction between the MgAl 2 O 4 spinel and PdO species, favoring the dispersion and stability of the species. In addition, the effects of Pd particle size on CH 4 combustion were also investigated. It was found that the catalytic activity of Pd/MgAl 2 O 4 , with a strong metal-support interaction, showed a volcano-shaped dependence on the size of Pd particles.
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）