CATALYSIS LETTERS
·
2024
·
IF 2.3
Liu Hang,Liu Sixu,Liang Yaozhen,Sun Yifei,Xiong Haifeng
Palladium (Pd)-based catalysts are widely used for CO 2 hydrogenation reactions due to the capability to activate H 2 , which enhances the overall CO 2 conversion. However, most of the current Pd catalysts reported show high CO 2 conversion only at higher temperature, and the exploration of efficient catalyst enabling low temperature conversion (180–300 °C) is of importance. In this study, a series of Pd-B/ZnAl 2 O 4 catalysts were synthesized via in-situ doping, resulting in the Pd crystal transformation induced from crystal to amorphous. The catalytic hydrogenation activity of the amorphous Pd-B catalyst reaches its zenith at a Pd-B mole ratio of 1:2, accompanied by the superior catalysis stability in CO 2 hydrogenation. Various characterization techniques, including XRD, CO-DRIFTS, H 2 -TPR, XPS and TEM, were used to investigate the properties of the Pd-B/ZnAl 2 O 4 catalyst. The results showed that the Pd-B/ZnAl 2 O 4 catalyst exhibited higher dispersion and better CO 2 conversion efficiency compared to unmodified Pd catalyst. Additionally, the methanol space–time yields are nearly doubled when the B decoration is employed. At 280 °C, CO 2 conversion was improved and methanol selectivity remained at ~ 65%. This study provides valuable insights into the design and optimization of Pd-B based catalysts for CO 2 hydrogenation at low temperatures. Graphical Abstract
研究领域:
催化化学
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能源化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Gengrui Zhang,Yan Li,Yong Chen,Xinning Hao,Xianhua Zhang,Shuai Wang,Jingdong Lin,Yong Wang,Shaolong Wan
The development of Ni-based syngas methanation catalysts with superior thermal stability remains a formidable challenge, which typically requires the use of a high Ni loading and a recipe containing very complex components. Herein, a novel Ni catalyst using a ZnAl2O4 spinel support was designed and prepared by an isopropanol-mediated controlled hydrolysis method, which demonstrated excellent reactivity and stability toward the syngas methanation reaction. Moreover, the 35% Ni/ZnAl2O4 catalyst still maintained a high reactivity after steam treatment at 750 °C, while the 35% Ni/Al2O3 counterpart suffered a nearly complete loss of reactivity during such an accelerated test. The detailed characterization reveals that the drastic deactivation of Ni/Al2O3 after steam treatment is attributed to the favored formation of NiAl2O4 under the severe reaction atmosphere, resulting in the loss of active Ni. In contrast, the employment of the highly stable ZnAl2O4 support can not only inhibit the sintering of supported Ni particles due to their strong interaction but also avoid the loss of the active Ni component by preventing the formation of NiAl2O4. This work sheds light on the critical role and the intrinsic mechanism of the spinel support for the construction of the desired methanation catalysts. The mechanistic scenario revealed in this work provides an important and novel solution to overcome the deactivation problem not only useful for methanation catalysts but also valid for most other supported metal catalysts commonly used in the reaction processes that require severe reaction conditions.
研究领域:
催化化学
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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
·
2020
·
IF 16.683
Xinbao Zhang,Guanghui Zhang,Wei Liu,Fei Yuan,Jianyang Wang,Jie Zhu,Xiao Jiang,Anfeng Zhang,Fanshu Ding,Chunshan Song,Xinwen Guo
Identifying the surface structure of heterogeneous catalysts is critical for understanding the active sites, but it remains challenging due to the difficulty in characterizing the catalytic surfaces especially at elevated temperatures. Zn-based catalysts are high-efficiency alternatives for high-temperature methanol synthesis from CO 2 , as well as in bifunctional catalysts for hydrocarbons synthesis. Herein, the surface reconstruction of ZnAl 2 O 4 spinel during CO 2 hydrogenation reaction was investigated using detailed spectroscopic characterization. The results indicate that the reaction-driven surface reconstruction leads to the formation of amorphous ZnO on the ZnAl 2 O 4 surface, which is accompanied by the increasing catalytic activity for methanol production. Kinetic analysis, STEM and in situ FTIR results indicate that the amorphous ZnO boosts the methanol formation rate by promoting the activation of H 2 . This study provides useful insight into the structure-activity relationship of zinc-based catalysts for CO 2 hydrogenation and future design of new catalysts.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Frontiers of Materials Science
·
2019
·Vol. 14
·期 1
·73-80
·
IF 1.701
Zhang Dong,Chen Jingxin,Du Chunyu,Zhu Bingjun,Wang Qingru,Shi Qiang,Cui Shouxin,Wang Wenjun
ZnAl 2 O 4 :Cr 3+ hollow spheres composed of secondary nanoparticles with single spinel phase were fabricated using carbon templets. Monitoring the emission of 687 nm, two wide excitation bands attributed to the electrons of Cr 3+ transiting from 4 A 2g ( 4 F) → 4 T 1g ( 4 F) and 4 A 2g ( 4 F) → 4 T 2g ( 4 F) were observed. The broad excitation band at about 397 nm was asymmetric and consisted of two peaks, indicating that there was a trigonal distortion existing in the lattices. The intensity of all emitting peaks revealed sharp increasing trend with the sintering temperature increase, and the intensity of emission at 698 nm assigned to inversion defects was more intense than that of emission at 687 nm assigned to octahedral Cr 3+ ions in the undistorted spinel lattice. The samples with higher synthesized temperature revealed longer decay time, and the relative weightage of shorter decay time component decreased with the increase of sintering temperature, indicating that the surface defects decreased.
研究领域:
材料科学
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光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
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2017
·Vol. 85
·期 1
·121-131
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IF 1.575
Zhang Dong,Guo Qingjie,Ren Yanfang,Wang Changzheng,Shi Qiang,Wang Qinglin,Xiao Xia,Wang Wenjun,Fan Quli
ZnAl 2 O 4 :Cr 3+ crystals were synthesized by using sol–gel method at 1000 °C. The results showed that with the concentration of Cr 3+ in spinel lattices increasing, the x-ray diffraction peaks shifted toward lower diffraction angles, and the grain size revealed a rapid increase and became invariable when the Cr 3+ dopant concentration was above 0.7 mol%. All the samples showed a series of emission peaks ranging from 660 to 730 nm assigned to spin-forbidden 2 E g → 4 A 2g transition of Cr 3+ ions in spinel lattices. The intensity of emission peaks revealed a strong dependence on the Cr 3+ concentration. An additional emission peak at 740 nm was present when the Cr 3+ ions concentration was above 0.5%. All emission peaks were quenched when the Cr 3+ concentration reaches 1.3 mol%. The results of x-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) suggested that the Cr 3+ ions occupied the octahedral sites in spinel lattices, and with the Cr 3+ concentration increasing, the exchange interaction and coupling interaction between Cr–Cr were enhanced and the antisite defects related to Zn in octahedral sites increased. Graphical abstract
研究领域:
材料科学
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固体物理
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光学材料
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无机化学
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纳米技术
✓ 已验证
DOI
高影响因子
ACS Applied Optical Materials
·
2023
·
IF 0
Jie Zhu,Yang Sun,Meng-Xin Duan,Zheng-Wu Wang,Xin Tan,Zhen Yu,He-Fang Wang
The fast and accurate detection of β-lactamase is a prerequisite of customized treatments and food safety. We present a pretreatment-free dual-excitation three-mode detection of β-lactamase by using ZnAl2O4:Cr3+ etched by ethylenediaminetetraacetic acid disodium (ZAO-EDTA) as a phosphorescent probe and nitrocefin as the signal mediator. The changes in the wavelength overlaps of UV–vis absorbance of nitrocefin upon interactions with β-lactamase and the dual excitation of ZAO-EDTA enable the design of three detection modes: i.e., the enhanced emission when excited at 393 nm, the quenched emission when excited at 533 nm, and the ratio of enhanced excitation of 393 nm and decreased excitation of 533 nm to determine β-lactamase. All three modes have a wide linear range, high sensitivity and selectivity, and fine anti-interference capability. The lowest limit of detection is observed in the ratiometric excitation mode (0.2 U·L–1), and the proposed method can directly detect β-lactamase in bacteria and milk samples without any pretreatments, with the spiked recoveries of 95.3–113% and relative standard deviation < 3.1%. Therefore, the proposed method would be attractive for the detection of β-lactamase in a complex sample, and the ZAO-EDTA probe can be widely used to establish other excitation ratiometric optosensings by changing other signal mediators.
研究领域:
分析化学
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生物传感
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食品安全
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微生物学
✓ 已验证
DOI
Chem
·
2023
·
IF 23.5
Qiao Han,Pan Gao,Kuizhi Chen,Lixin Liang,Zhenchao Zhao,Xinlong Yao,Dong Xiao,Xiuwen Han,Guangjin Hou
The urgent need for efficiency improvement in the oxide-zeolite bifunctional syngas-to-hydrocarbon catalysis necessitates in-depth mechanistic insights into this reaction, especially for the initial syngas conversion over the oxide component, which remains poor. Herein, we comprehensively investigated syngas conversion over a representative ZnAl 2 O 4 spinel oxide with state-of-the-art solid-state NMR technologies. Notably, specific surface dual active sites for syngas activation with –Al IV –OH···Zn III – structure were unambiguously identified. More importantly, the dynamic evolution of the reaction intermediates and active sites during the reaction process was elaborated at atomic level by a series of double resonance and multi-dimensional correlation NMR experiments. In combination with in situ spectroscopic characterizations, we revealed the full cycle of the formate-methoxy-based pathway for the syngas-to-methanol conversion via synergistic interplay of the dual active sites. The in-depth atomic-level understanding of the catalytic mechanism will be beneficial to further rational design of high-performance catalysts for syngas conversion.
研究领域:
催化化学
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表面科学
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材料化学
·
物理化学
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能源化学
·
多相催化
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Lixin Song,Guobin Liu,Zhenping Qu
Cu/ZnAl 2 O 4 spinel is a promising catalyst for CO 2 -to-methanol due to its dual-site H 2 activation. However, controlling surface properties and metal-support interactions (MSI) through the coordination environment of spinel cations remains underexplored. Herein, the occupancy of Zn 2+ and Al 3+ cations in Cu/ZnAl 2 O 4 spinel is fine-tuned by manipulating the calcination atmosphere. More disordered structures (AlO 4 and ZnO 6 ) observed on the CZA-Ar catalyst benefit the creation of oxygen vacancies and surface hydroxyl groups, which facilitate the formation of highly dispersed small-sized Cu species. This enhances MSI and hydrogen spillover effects, thereby boosting CO 2 conversion and the space-time yield (STY) of methanol. High-pressure in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) results reveal that the crucial formate intermediates form at tetrahedral sites in ZnAl 2 O 4 spinel, with more Al-HCOO - species observed on the CZA-Ar catalyst due to the formation of AlO 4 . This work advances the understanding of spinel catalysts in CO 2 hydrogenation to methanol.
研究领域:
催化化学
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材料科学
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2019
·
IF 5.128
Min Zhong,Yuanyuan Guo,Jungang Wang,Congbiao Chen,Zhancheng Ma,Litao Jia,Bo Hou,Debao Li
The development of alternative to silicon carbide (SiC) holds great promise in energy and environmental related catalysis because the harsh preparation process and high cost limit its large-scale application. In this work, the core-shell structured ZnAl 2 O 4 @Al ceramic-metal composites (Zn-Al-T) are prepared from low cost metallic Al powder by a facile and environment-friendly approach to replace silicon carbide for Co-based Fischer-Tropsch synthesis (FTS, a typical strong exothermic heterogeneous catalytic reaction). The composition, thermal conductivity, surface chemical properties and pore configuration of the ZnAl 2 O 4 @Al composites can be easily modulated by controlling the calcination condition. Among Zn-Al-T composites, the Zn-Al-650 and Zn-Al-750 samples demonstrate optimum coupling of physicochemical properties, i.e., robust chemical stability, meso -macropore structure (wide mesopore and high macroporosity) and high thermal conductivity. Thus, the excellent FT performance (low CH 4 selectivity and high selectivity to C 5+ ) was obtained on the Co/Zn-Al-650 and Co/Zn-Al-750 catalysts. The heat transfer experiments were conducted on a special tubular fixed-bed reactor (I.D. = 22 mm) under near-industrial conditions. At similar reaction rates, the effective radial thermal conductivity coefficient (k eaff ) in the Co/Zn-Al-650 catalyst bed is 3–4 times and 1–2 times that in the Co/Al 2 O 3 and Co/SiC catalyst beds respectively, resulting in a more uniform temperature distribution in Co/Zn-Al-650 catalyst bed. In addition, the ZnAl 2 O 4 @Al composite has wide application prospect in strong exothermic/endothermic catalytic system owing to its high thermal conductivity, adjustable physico-chemical properties, facile preparation method and low cost.
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
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Zhengting Xiao,Dongcai Shen,Kai Guo,Guangci Li,Wentai Wang,Xuebing Li,Song Chen,Chunhu Li
Cu-based catalysts were synthesized utilizing the ZnAl 2 O 4 spinel as supports for the selective hydrogenation of methyl stearate to stearyl alcohol. The presence of Zn atoms inhibited the agglomeration of the particles of Cu species in the reduction process, promoting the distribution of Cu species on the catalyst surface, which will enhance hydrogen activation and selective hydrogenation activity. DFT calculations show that the bond energies of the C-O bonds on both sides of the ester group decrease with the adsorption of the ester molecule onto Cu + species, and the C-O bond energy on the methyl side is lower than that on the carbonyl side. However, because the carbonyl carbon is more susceptible to nucleophilic attack, the C-O bond on the carbonyl side is more easily broken. In addition, the oxygen vacancies of the supports promote hydrogen spillover and the adsorption and activation of ester groups, which further enhance the selective hydrogenation activity of the catalyst on methyl stearate.
研究领域:
催化化学
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材料科学
·
理论计算
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2018
·Vol. 29
·期 10
·8293-8302
·
IF 2.324
Qin Zhuozhuo,Liu Wenxia,Li Zhenzhen,Chen Huabin,Li Guodong,Yu Dehai
Doping lanthanide ions in metal oxides is an efficient way to develop visible and near-infrared (NIR) active photocatalysts. Herein, we present a method to develop NIR active photocatalyst via doping Er 3+ into ZnO/ZnAl 2 O 4 multi-phase oxides by isomorphous replacement of Al 3+ with Er 3+ during the preparation of Zn/Al-hydrotalcite-like compound, specifically, the calcination of the hydrotalcite-like compound at 900 °C. The as-prepared Er 3+ -doped catalyst and its precursor were characterized using X-ray diffraction technique, scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and near-infrared-visible-ultraviolet diffused reflectance spectroscopy. It was found that the doping of Er 3+ causes lattice expansion for ZnO and ZnAl 2 O 4, and yields optical absorptions at visible and NIR light regions. The obtained Er 3+ -doped ZnO/ZnAl 2 O 4 multi-phase oxides produce superoxide and hydroxyl radicals in the photocatalytic process, and show enhanced ultraviolet (UV) photocatalytic activity on degradation of methyl orange, compared to undoped ZnO/ZnAl 2 O 4 multi-phase oxides. The Er 3+ -doped ZnO/ZnAl 2 O 4 multi-phase oxides also possess visible and NIR light photocatalytic activities, and its photocatalytic activity is rather stable under UV, visible and NIR light irradiation. This work provides a new way for doping of lanthanide ions in metal oxides and designing full-spectrum photocatalysts.
研究领域:
材料科学
·
光催化
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2017
·
IF 3.133
Xingzhong Guo,Pengan Yin,Wei Lei,Hui Yang,Kazuyoshi Kanamori,Kazuki Nakanishi
Hierarchically porous ZnAl 2 O 4 spinel monolith derived from ionic precursors has been successfully prepared via the sol-gel route accompanied by phase separation in the presence of poly (ethylene oxide) (PEO) and propylene oxide (PO). Appropriate amounts of PEO as a phase-separation inducer and PO as a gelation mediator allow the formation of the xerogel with bicontinuous macrostructure and a monolithic shape. The macropore size of the resultant dried gel is mainly distributed in the range of 0.2–1 μm, and the whole porosity is about 65%. The dried gel is constructed by crystalline Zn Al hydrotalcite, becoming amorphous after heat-treated at 300–500 °C in air, and is further transformed into single phase ZnAl 2 O 4 spinel with plate-like shape at 600 °C. The macroporous structure is well maintained while the porosity increases to 75% and the surface area rises to 109 m 2 g −1 after heat-treatment.
研究领域:
材料科学
·
无机化学
·
多孔材料
·
功能陶瓷
·
纳米结构材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）