RSC Advances
·
2017
·Vol. 7
·期 50
·31466-31474
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IF 3.108
Jun Qu,Xiaoman He,Xuewei Li,Ziqiang Ai,Yujie Li,Qiwu Zhang,Xinzhong Liu
An amorphous photocatalyst was prepared via simple dry milling of Zn basic carbonate (Zn4CO3(OH)6·H2O) and Al hydroxide (Al(OH)3) as a precursor of Zn–Al layered double hydroxide (LDH) and the precursor was agitated in water to simply synthesize the Zn–Al LDH for comparison. The adsorption and photocatalytic activity of the Zn–Al LDH and the precursor were studied via the removal of methyl orange (MO) and decoloration of MO under ultraviolet light irradiation in aqueous solution, respectively. The precursor exhibits much higher decoloration efficiency towards MO than the Zn–Al LDH product because of the synergistic effect of the intercalation reaction and its photocatalytic activity. The amorphous precursor could easily incorporate MO molecules to form MO intercalated LDH, allowing easy access of the organic pollutant to the photocatalyst sample, resulting in an obvious improvement in photocatalytic performance. The novel idea to use the precursor sample instead of the synthesized final product may be applied in other fields to increase the required performances.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Ruixin Yan,Xiuping Feng,Long Kong,Qun Wan,Weilin Zheng,Takeshi Hagio,Ryoichi Ichino,Xinde Cao,Liang Li
Hexavalent Chromium (Cr(VI)) in water is a public health concern and has been a challenging research subject in environmental field for many years. Herein, a novel composite material consisting of amorphous iron sulfides supported on hydrotalcites (FeS/HTs) was synthesized by “calcination-reconstruction-calcination” process, which enables homogeneous distribution of iron and sulfur on the surface of hydrotalcites (HT). The composite (mass ratio of FeS/HT was 1/2) could effectively remove over 98% of Cr(VI) within 10 min. A pseudo-second-order kinetic model and a Langmuir isotherm model were well fitted the sorption data with a maximum removal capacity of 206.2 mg/g. The superior adsorption capacity of FeS/HTs could be attributed to the combination of the advantages of abundant adsorption sites on HT and powerful reduction properties of iron sulfides. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis suggested the adsorbed Cr(VI) on the surface and interlayer of FeS/HTs had been reduced to Cr(III) by reductant iron and sulfur. This study demonstrated that FeS/HTs has potential application prospects in Cr(VI) removal.
研究领域:
环境科学
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材料科学
✓ 已验证
DOI
高影响因子
GREEN CHEMISTRY
·
2022
·Vol. 24
·期 22
·8840-8852
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IF 11.034
Zongyang Liu,Yuan Tan,Jie Li,Xiuli Li,Yan Xiao,Juan Su,Xingkun Chen,Botao Qiao,Yunjie Ding
Aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is a promising alternative route to produce renewable biodegradable plastics, which has stimulated intense interest in recent years. Supported gold catalysts have shown great potential for this reaction, but the selectivity and stability need to be improved. In addition, the requirement for base additives makes the process less effective and sustainable. Herein, highly active and selective Au–Ag bimetallic nanoclusters supported on MgAl-hydrotalcite (HT) were developed for HMF oxidation to FDCA under base-free reaction conditions using molecular oxygen as the oxidant. The presence of small amounts of Ag (0.034–0.065 wt%) in Au25 clusters greatly enhanced the catalytic reaction rates and selectivity for HMF tandem oxidative steps, leading to both high conversion of HMF (>97%) and high yield of FDCA (>95%). Besides, the catalyst stability was also enhanced by the addition of Ag. The characterization results suggested that the substitution of Ag atoms modified the electronic structure of Au while likely maintaining the primary geometry. Thus, a significant synergistic effect could be observed over trace Ag modified Au–Ag bimetallic nanoclusters. The present work provides new insight into the alloying effect, and helps understand highly efficient Au-based catalysts for aerobic oxidation of biomass derived molecules under base-free conditions.
研究领域:
催化化学
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可再生资源化学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2021
·Vol. 22
·期 16
·8668
·
IF 5.924
Jie Li,Shiyi Wang,Huayin Li,Yuan Tan,Yunjie Ding
The synthesis of ester compounds is one of the most important chemical processes. In this work, Zn-Mg-Al mixed oxides with different Zn2+/Mg2+molar ratios were prepared via co-precipitation method and supported gold nanoclusters to study the direct oxidative esterification of aldehyde and alcohol in the presence of molecular oxygen. Various characterization techniques such as N2-physical adsorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and CO2temperature programmed desorption (TPD) were utilized to analyze the structural and electronic properties. Based on the results, the presence of small amounts of Zn2+ions (~5 wt.%) provoked a remarkable modification of the binary Mg-Al system, which enhanced the interaction between gold with the support and reduced the particle size of gold. For oxidative esterification reaction, the Au25/Zn0.05MgAl-400 catalyst showed the best performance, with the highest turnover frequency (TOF) of 1933 h−1. The active center was believed to be located at the interface between metallic gold with the support, where basic sites contribute a lot to transformation of the substrate.Keywords:gold catalyst;cluster;hydrotalcite;oxidative esterification;methyl isobutyrate
研究领域:
化学工程
·
催化材料
✓ 已验证
DOI
PubMed
高影响因子
ACS Applied Engineering Materials
·
2023
·
IF 0
Peng Liu,Xiulin Huang,Zhiguang Guo
Based on the ion exchange properties of hydrotalcite, dense hydrotalcite films with citric acid or tetraborate ions were prepared by a one-step hydrothermal method on aluminum flake, and superhydrophobic modified by sodium laurate to obtain a superhydrophobic corrosion resistant film with a water contact angle of about 154° and a sliding angle of less than 5°. The super hydrophobicity of the film can greatly slow down the infiltration of water and corrosive ions. The LDHs can release corrosion inhibitor ions to promote the formation of the passivation layer and can absorb chloride ions to reduce the corrosion of the metal. In addition, a very uniformly grown hydrotalcite film was obtained using urea. Electrochemical analysis of the coating after immersion in 3.5 wt % NaCl solution has shown that U-LDH-SC/SL film has the most positive corrosion potential (−0.056 eV), the best corrosion resistance, and long-term stability, which is related to the larger layer spacing and more uniform growth.
研究领域:
材料科学
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表面工程
·
腐蚀防护
✓ 已验证
DOI
CORROSION SCIENCE
·
2024
·
IF 7.4
Teng Xu,Lei Yu,Ji-Ming Hu
Zn-Al layered double hydroxide (LDH) pretreatment layer was prepared by a novel two-step electrochemical method on galvanized steel surface from a precursor solution containing Al 3+ -only. In the first step, anodic currents are applied to Zn deposit to produce Zn 2+ in solution near the substrate surface. Cathodic currents are then applied to ensure the cathodic deposition of LDH film. The obtained LDH coatings not only provide excellent adhesion to the metal surface, but also enhance the adhesion between metal substrate and the top epoxy coatings. The “LDH/epoxy” painting system can protect galvanized steel from rusting for at least 150 days.
研究领域:
材料科学
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电化学
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表面工程
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2024
·
IF 8.2
Minwang Laipan,Min Zhang,Ziyu Wang,Runliang Zhu,Luyi Sun
The efficient and waste-free recovery of heavy metals is critical for heavy metal wastewater treatment . In this work, we explored how heavy metals can be recovered as valuable chemicals in the presence of crystal seeds. Hydrotalcite (one kind of layered double hydroxides (LDHs)) was used as crystal seeds to recover Zn 2+ in the presence of Al 3+ from water (i.e., seed-Zn 2+ -Al 3+ system), which was compared with the monometallic heterogeneous system (seed-Zn 2+ ) and direct coprecipitation (Zn 2+ -Al 3+ ) system. Our results demonstrated that the seed-Zn 2+ -Al 3+ system possessed a recovery rate of 2.6–2.8 times and a recovery kinetic rate of 2.7–5.9 times higher than those of the other two systems. Differing from the latter two systems, hydrotalcite seeds could induce Zn 2+ and Al 3+ to form ZnAl-LDH in seed-Zn 2+ -Al 3+ . Interestingly, the ZnAl-LDH presents a compositional divalent/trivalent cation molar ratio of ca. 3, which is comparable with the value in the hydrotalcite. It was demonstrated that the hydrotalcite seeds could act as a template to significantly induce the formation of ZnAl-LDH complying with the seed's structure and compositional ratio. Similar induction effect of seeds as the Zn 2+ system was further verified in Cu 2+ systems. This work provides a novel strategy for efficient recovery of heavy metals with product selectivity .
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
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2022
·
IF 4.778
Zhemin Zou,Jie Wang,Jun Qu,Panfei Dong,Zhigao Xu
The ionic rare earth elements (REEs) was mainly recovered by in-situ leaching process. The concentration of rare earth ions in the leaching solution after long-term leaching process would be too low for traditional precipitation process for REEs recovery. The adsorption process was ideal for the low concentration REEs recovery. In this study, Zn–Al LDH precursor were successfully synthesized by mechanochemical method for the adsorption of REEs (including La − , Eu 3+ and Er 3+ ). X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron energy spectrometer (XPS), and Zeta potential test was applied for adsorption mechanism illustration. The maximum adsorption capacity of the Zn–Al LDH precursor for La 3+ , Eu 3+ and Er 3+ reached 492 mg/g, 346 mg/g, and 1154 mg/g which was significantly higher than other types of adsorbents. The adsorbed REEs on the Zn–Al LDH was hard to be desorbed. The Zn–Al LDH precursor after REEs adsorption could be directly used as high content REEs resources for further process.Therefore, the Zn–Al LDH precursor could be a promising adsorbent for REEs recovery in practical application.
研究领域:
材料科学
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环境科学
✓ 已验证
DOI
高影响因子
MOLECULES
·
2010
·Vol. 15
·期 8
·5139-5152
·
IF 1.738
Lu Lin,Ying Liu
A series of Ni-based catalysts were prepared using hydrogen reduction of Ni/Al hydrotalcite-like compounds (Ni/Al HTlcs) synthesized by coprecipitation. The physico-chemical properties of Ni/Al hydrotalcite-like compounds and the corresponding Ni-based catalysts were characterized using inductively coupled plasma (ICP), BET surface areas, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) techniques. The results indicated that Ni/Al HTlcs with layered structures could be successfully prepared by the coprecipitation method, and the characteristic HTlcs reflections were also observed in the XRD analysis. The NiO and Ni0phases were identified in all Ni-based catalysts, which displayed randomly interconnected pores and no layer structures. In addition, the studies also found the Ni/Al HTlcs and Ni-based catalysts had high specific surface areas, low pore volumes and low pore diameters. The catalytic hydrogenation of ethyl acetate to ethanol with Ni-based catalysts was also investigated. Among the studied catalysts, RE1NASH-110-3 showed the highest selectivity and yield of ethyl acetate to ethanol, which were 68.2% and 61.7%, respectively. At the same time, a major by-product, butyl acetate, was formed due to an ester-exchange reaction. A proposed hydrogenation pathway for ethyl acetate over Ni-based catalysts was suggested.Keywords:hydrogenation;ethyl acetate;ethanol;Ni/Al hydrotalcite-like compounds
研究领域:
化学工程
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF VINYL & ADDITIVE TECHNOLOGY
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2024
·
IF 3.8
Xue Mei,Pingping Jiang,Pingbo Zhang,Zhixuan Cui,Xiaoyuan Zhu,Shijun Chen,Xunxun Sheng,Jingang Gao,Hang Gao
To make the hydrotalcite uniformly dispersed in polyvinyl chloride (PVC) and enhance its thermal stability, cinnamate-intercalated calcium aluminum hydrotalcite (CaAl-cinnamate-LDHs) underwent organic modification with cetyltrimethylammonium bromide/sodium dodecyl sulfate/polyethylene glycol (CTAB/SDS/PEG). The structures of modified hydrotalcite were characterized using x-ray diffractometer, scanning electron microscope, particle size analysis, and water contact angle test. The thermal stability was assessed through thermal aging oven experiment, Congo Red experiment, and thermogravimetric experiment, revealing their exceptional performance. Simultaneously, the synergistic effect of PEG-LDHs with auxiliary thermal stabilizers was examined, with epoxy soybean oil proving to be the most effective, which made the PVC sample incompletely black within 120 min. Mechanical properties and dynamic thermomechanical analysis indicated that the overall mechanical characteristics of the PVC samples with modified hydrotalcite were significantly superior to the unmodified CaAl-cinnamate-LDHs. Additionally, the optical performance test demonstrated excellent transparency in the PEG-LDHs/PVC sample. Through analyzing the thermal stability mechanism, it was indicated that hydrotalcite effectively absorbed HCl. Furthermore, the combination of PEG-LDHs and ESO replaced unstable Cl atoms and reacted with conjugated double bonds, thereby reducing the aging and discoloration of PVC. Highlights The modified hydrotalcite preparation process was simple and easy to operate. The CTAB/SDS/PEG-LDHs/PVC samples exhibited excellent thermal stability. Mechanical properties of the PVC samples with modified hydrotalcite were significantly superior to the unmodified CaAl-cinnamate-LDHs.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Bo Xu,Guoxiang Pan,Xinyu Fan,Haijie Zhou,Chengcong Qiu,Yuhua Guo,Minhong Xu,Jingwei Sun,Xinhui Xia
Conventional jungle-camouflage materials exhibit four prominent vibration peaks (green peak, red-edge, plateau, and water absorption peaks) on the green-vegetation spectrum. However, they cannot accurately simulate the water peaks of green vegetation, and this limits their application efficiency and considerably hinders their further development. Here, an environment-friendly camouflage coating comprising MgAlFe-LDHs-CA, ZnAl-LDH-AG, and BiVO 4 is proposed to facilitate the precise simulation of NIR spectrum of green-vegetation. Next, the developed material is characterized by XRD, FT-IR, TG-DTA, SEM and XPS techniques. The characterization results reveal that the newly developed jungle-camouflage-coating material achieves a 97.56 % simulation of green vegetation. Additionally, the similarity analysis results of the prepared camouflage coating confirm that it simulated all the spectral characteristics of green vegetation. Thus, we propose a new environment-friendly hydrotalcites camouflage material, thereby offering a new research direction in the development of camouflage materials.
研究领域:
材料科学
·
光谱学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Yanqing Shi,Cai Guo,Huajing Zhou,Liang He,Shaoyun Shan,Tianding Hu
Rational modulation of the local electron density of Cu active site is the key to improve the efficient transfer hydrogenation (CTH) of furfural (FF) on the surface of catalysts with low Cu-loadings. In this paper, a CuMgAl/LSC catalyst with lower Cu content (<3.5 % wt ) was prepared by using porous biochar as a carrier and exploiting the local dispersion and electron-modulation effects of structural elements of hydrotalcite laminates. CTH experiments showed that the conversion of FF and the selectivity of FA could reach more than 99.0 % in isopropanol solution at 170 °C and within 1 h. Catalyst characterization and density functional theory (DFT) calculations demonstrated that the Cu(I) species was the main active site during the CTH process of FF. Doping laminate metals (i.e., Mg, Al) can not only form electron-rich centers by local electron modulation of the active site through the coordination structure of Cu-O-M, lowering its D-band center and achieving higher catalytic activity; Due to the Jahn-Teller effect, the local spatial misalignment of Cu sites formed, which can reduce the risk of over-hydrogenation and improve the FA selectivity. In addition, it can be also found that the Coulomb tractive force of reactive intermediates can lead to the crystal surface reconstruction and structure deterioration of Cu species. The new discovery of the deactivation mechanism can provide a reference for the future design of copper-based catalysts in CTH process of FF.
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
危险品化学品经营许可证（带存储）