INORGANIC CHEMISTRY
·
2021
·
IF 5.165
Hang Ruan,Zhongnan Guo,Jiawei Lin,Kunjie Liu,Lingling Guo,Xin Chen,Jing Zhao,Quanlin Liu,Wenxia Yuan
The Pb-free hybrid-layered-double perovskites (HLDPs) have been proposed as green and stable semiconducting materials for optoelectronic devices, but the synthesized members are still limited. Here, we report the synthesis of three new HLDPs, (C8H20N2)2AgMBr8 (M = In, Sb, and Bi), by a solution method using 1,4-bis(ammoniomethyl)cyclohexane (C8H20N22+) as the organic spacing cation. All three of these HLDPs show ⟨100⟩-oriented layered structures with Ag and In/Sb/Bi order arranged in corner-sharing octahedral layers. The first-principle calculations indicate the indirect-gap nature of (C8H20N2)2AgInBr8 and (C8H20N2)2AgSbBr8, while their Bi counterpart shows a direct band gap after considering spin–orbit coupling. The band gaps obtained by diffuse-reflectance spectroscopy are 3.11, 2.60, and 2.70 eV for M = In, Sb, and Bi, respectively. (C8H20N2)2AgInBr8 shows a broadband red emission centered at 690 nm, and it is mainly attributed to the self-trapped-excitons mechanism. Our results not only provide a series of new “Pb-free” HLDPs with chemical diversity but also help us to further understand the structure–property relationships of HLDP materials.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Yi Yang,Huiping Zhang,Haoxin Huang,Ying Yan,Xinya Zhang
Degradation of organic pollutant through catalytic wet peroxide oxidation (CWPO) is becoming more and more important in modern industry. As a commonly used organic synthetic material, excessive discharge of m-cresol may lead to severe damage of the environment and become a potential threat to human health. In this study, m-cresol was degraded over novel iron loaded carbon nanotube microfibrous composite (Fe-CNT-MF) catalyst packed fixed bed reactor. The kinetic parameters were first optimized, and then the deactivation mechanism of catalyst was also studied. The optimization model showed that total organic carbon (TOC) conversion of m-cresol degradation can reach about 70% under optimum conditions. Then the catalyst deactivation test was conducted with four consecutive runs (32 h in total). Fe-CNT-MF performed high m-cresol and TOC conversions (99% and 40%, respectively) as well as high H 2 O 2 decomposition efficiency (100%) with no iron leaching. Besides, the effect of co-existing organic pollutants on m-cresol degradation was investigated with presence of 4-Ethylphenol and 2,5-dimethylphenol. Fe-CNT-MF exhibited good catalytic activity in multi-pollutant wastewater with 99% conversion for all pollutants. Finally, deactivation analysis results showed that the deactivation mechanism of Fe-CNT-MF included carbon deposition, surface property change and additional oxygen functionalities. A regeneration study was proceeded to further confirm the suggested mechanism, indicating that Fe-CNT-MF has a good regenerability.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2020
·Vol. 31
·期 24
·22375-22384
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IF 2.22
Wang Li,He Lin,Li Ji,Yu Yongsheng,Li Haibo
M-type strontium ferrite is a kind of magnetic functional material with wide application prospect. In this work, SrFe 12− x Al x O 19 (0 ≤ x ≤ 1) and Sr 1− y Ca y Fe 8 Al 4 O 19 (0 ≤ y ≤ 0.4) have been prepared by a hydrothermal method, and the effects of Al 3+ doping and Al 3+ and Ca 2+ co-doping on the magnetic properties have been investigated. X-ray diffraction analysis indicates all the samples are a hexagonal structure, and the shift of the diffraction peaks suggests that Al 3+ and Ca 2+ are successfully doped in SrFe 12 O 19 . Field emission scanning electron microscope images show the particles have the hexagonal shape with the size of 1.1–2.9 µm. Vibrating sample magnetometer reveals that the doping of Al 3+ and the co-doping Al 3+ and Ca 2+ can enhance magnetic properties of strontium ferrite. For example, the values of coercivity and the saturation magnetization of SrFe 8 Al 4 O 19 are 914.1 Oe and 44.0 emu/g, which are 3% and 117% enhancement compared with SrFe 12 O 19 , respectively. For Sr 1− y Ca y Fe 8 Al 4 O 19 , coercivity and saturation magnetization increase from 914.1 Oe and 41.8 emu/g to 1047.2 Oe and 50.2 emu/g when the Ca 2+ doping concentration increases from 0 to 0.4. Moreover, the effects of acid washing also on phase composition, morphology and magnetism are researched. The as-synthesized doping strontium ferrite will be useful for the applications in security switching and recording media.
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RSC Advances
·
2020
·Vol. 10
·期 8
·4554-4560
·
IF 3.119
Su Xunwen,Zhu Liqun,Li Weiping,Liu Huicong,Ye Hui
CeO2/polymer nanoparticles have drawn considerable attention for their excellent UV absorption properties. However, many challenges still exist in the successful incorporation of ceria into the polymer matrix for the easy agglomeration and photocatalytic activity of CeO2 nanoparticles. Herein, we address these issues by constructing three-layer structured nanoparticles (M-CeO2@SiO2) and incorporating them into a polymer matrix through a mini-emulsion polymerization process. During this process, small-sized nano-ceria became uniformly anchored on the surfaces of monodisperse silica particles first, and then the particles were coated with an MPS/SiO2 shield. The morphology and dispersion of the nanoparticles were investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The performance of the hybrid films was characterized using UV-vis absorption spectroscopy (UV-vis) and water contact angle (WCA) measurements. Results showed that the M-CeO2@SiO2 nanoparticles exhibited a three-layer structure with a mean diameter of 360 nm, and they possess good compatibility with acrylic monomers. After the addition of M-CeO2@SiO2, hybrid films exhibited enhanced UV absorption capacity as expected, accompanied by an obvious improvement in hydrophobicity (the water contact angle increased from 84.2° to 98.2°). The results showed that the hybrid films containing M-CeO2@SiO2 particles possess better global performance as compared with those containing no particles.
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Journal of Materials Chemistry C
·
2020
·Vol. 8
·期 22
·7322-7329
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IF 7.059
Da Chen,Fulong Dai,Shiqiang Hao,Guojun Zhou,Quanlin Liu,Christopher Wolverton,Jing Zhao,Zhiguo Xia
Organic–inorganic hybrid metal halides have received extensive attention owing to their versatile structures and optoelectronic properties. Herein, we report two lead-free metal halides, (PMA)3BiBr6 and (PMA)3SbBr6 [PMA+: (C6H5CH2NH3)+, as the abbreviation of phenylmethylammonium], which possess iso-structural zero-dimensional structures and crystallize in the monoclinic space group P21/c. (PMA)3BiBr6 and (PMA)3SbBr6 exhibit optical band gaps of ∼3.50 and 3.40 eV, respectively, and density functional theory calculations reveal their indirect bandgap behaviors. Upon 350 and 425 nm excitation, (PMA)3BiBr6 and (PMA)3SbBr6 exhibit broadband emission peaking at 510 nm and 625 nm with wide full-widths at half-maximum of ∼153 and 175 nm, respectively. The emission mechanism of the metal halides is attributed to self-trapped exciton emission. The relationship between the crystal structure and luminescence intensity is also discussed. Finally, both metal halides have high decomposition temperatures and are stable for long-term storage under ambient conditions, demonstrating their potential for optoelectronic applications.
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SENSORS AND ACTUATORS B-CHEMICAL
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2019
·
IF 6.393
Rui Liu,Bin Kong,Yun Chen,Xueping Liu,Shengli Mi
The helical structure is one of the most intriguing structures in nature; such an ingenious structure can be found from macromolecules to macroscopic areas, and the fabrication of helical structures has attracted research interest from mechanisms to applications. However, the fabrication of helical microfiber still remains a big challenge. In this study, a coaxial microfluidic device was made to continuously and controllably fabricate helical hydrogel microfibers with flexible shape by simply adjusting the flowrates. Various experimental conditions that can influence the diameter (d), pitch (p) and amplitude (A) of these formed coiled fibers were discussed. For the first time, the effects of G/M ratio of the alginates on the microfiber coiling phenomenon were examined. Additionally, magnetically responsive helical fibers were synthesized, and it is envisioned that hydrogel helical structure microfibers are highly versatile in different area, such as micro sensors, soft actuators and medical applications.
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CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Wenqi Yang,Fuxing Ye,Shuai Yan,Lei Guo
The corrosion of YSZ TBCs attacked by calcium–magnesium–aluminosilicate (CMAS) is a serious problem. Yttrium tantalite (YTaO 4 ), a new kind of potential thermal barrier ceramic material, was expected to replace the YSZ to manufacture the TBCs because of its great thermophysical characteristics. In this study, porous YTaO 4 ceramic pellets, instead of actual TBCs, were used to investigate the CMAS corrosion resistance at 1250 °C. Results indicated that CMAS couldn't cover the whole surface of YTaO 4 pellets homogeneously because of low wettability between liquid CMAS and YTaO 4 , in addition, there was almost no reaction layer after 4 h reaction. The XRD results showed that M-YTaO 4 , M′-YTaO 4 , Ca 2 Ta 2 O 7 and Y 2 Si 2 O 7 were the main four phases after reaction and there was no phase containing the elements of Mg and Al. Compared with YSZ TBCs, this new kind of potential thermal barrier ceramic material showed well resistance to CMAS corrosion.
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NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 47
·22672-22685
·
IF 3.925
Jing Wang,Mei Zhang,Feng Li,Huan Wang,Yanguang Chen,Hua Song
To deeply understand the role of P in hydrodeoxygenation (HDO), SiO2-supported Ni and Ni–P catalysts with different P/Ni ratios (x) were prepared. The as-prepared samples were characterized by various characterization methods. The HDO activity and product distribution over the Ni/SiO2 and N–P/SiO2-x were compared and the effects of x on the structure, acidity, formation mechanism of active phases and HDO performance were studied taking m-cresol HDO as a model reaction. The results showed that the introduction of P promotes the formation of smaller active sites and contributes to the creation of weak and medium strength acid sites through the formation of P–OH groups and Niδ+ in Ni2P. HDO over the Ni/SiO2 catalyst occurs mainly via the hydrogenation (HYD) route with 3-methyl-cyclohexanol (3-MCHnol) as the main product. However, for Ni–P/SiO2-x catalysts, methyl-cyclohexane (MCH) selectivity increases first and then decreases with the increase of x, reaching a maximum of 95% at x = 1. The acidity generated by the introduction of P contributes to increased MCH selectivity, while the dehydration of 3-MCHnol to MCH occurs mainly on acid sites. However, the excessively high P content (x ≥ 2.0) leads to a significant increase of MB (toluene) selectivity, which is associated with the increase in Ni(I) sites. About 100% m-cresol conversion was achieved with Ni–P/SiO2-1.0 when the m-cresol (g)/catalyst (g) ratio was 3, with MCH (99.4%) as the major product, showing great promise for deep HDO catalysis.
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Catalysts
·
2016
·Vol. 6
·期 2
·19
·
IF 2.964
Guozhu Liu,Yunxia Zhao,Jinhua Guo
High selectively catalytic conversion of lignin-based phenols (m-cresol,p-cresol, and guaiacol) intopara-/m-xylene was performed over Pt/HZSM-5 through hydrodeoxygenation andin situmethylation with methanol. It is found that thep-/m-xylene selectivity is uniformly higher than 21%, and even increase up to 33.5% form-cresol (with phenols/methanol molar ratio of 1/8). The improvedp-/m-xylene selectivity in presence of methanol is attributed to the combined reaction pathways: methylation ofm-cresol into xylenols followed by HDO intop-/m-xylene, and HDO ofm-cresol into toluene followed by methylation intop-/m-xylene. Comparison of the product distribution over a series of catalysts indicates that both metals and supporters have distinct effect on thep-/m-xylene selectivity.Keywords:m-cresol;hydrodeoxygenation;methanol;p-/m-xylene;methylation
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NEW JOURNAL OF CHEMISTRY
·
2013
·Vol. 38
·期 2
·777-783
·
IF 2.966
Aijuan Xie,Liang Ji,Shiping Luo,Zhiliang Wang,Yiyang Xu,Yong Kong
A nanocomposite of poly(m-phenylenediamine)/palygorskite (PmPD–PG) is facilely synthesized via in situ oxidative polymerization of m-phenylenediamine (mPD) on palygorskite (PG) and its reactive adsorbability to Cr(VI) is examined. PG in the nanocomposite plays important roles in the improvement of adsorptivity of Cr(VI). The pH value of the solution is increased after adsorption, which is quite different from Pb(II) adsorption with aromatic diamine polymers. This unusual removal behavior of Cr(VI) with PmPD–PG is due to the redox reaction between Cr(VI) and amino/imino groups on the PmPD chains.
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MATERIALS LETTERS
·
2013
·
IF 2.224
Rong Li,Shidong Ji,Yamei Li,Yanfeng Gao,Hongjie Luo,Ping Jin
Rectangular and plate-like VO 2 (M)@SiO 2 nanoparticles were fabricated by a combination method of hydrothermal synthesis and post annealing process. Rectangular VO 2 (B) nanoplates of 20–30 nm in thickness were hydrothermally synthesized, and VO 2 (B)@SiO 2 core–shell structure was formed using a modified Stober method. Protected by inert SiO 2 shell, after post annealing the VO 2 (B)@SiO 2 was transformed to VO 2 (M)@SiO 2 without deteriorating its original plate-like morphology. Much interestingly, numerous nanopores were formed inside VO 2 (M)@SiO 2 nanoparticles due to the difference in density between VO 2 (B) and VO 2 (M), which contributes to higher optical transmittance and thermal insulation . Thermochromic foils were fabricated using the core–shell nanoparticles, showing promising potential for smart window.
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CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Guijuan Wei,Xixia Zhao,Kun Du,Zhaojie Wang,Ming Liu,Shuo Zhang,Shutao Wang,Jun Zhang,Changhua An
To date, zero-dimensional carbon quantum dots (CQDs), as a new carbon nanomaterials, have attracted attention in the improvement of the electrical conductivity for electrode materials. However, few attempts have been made to the use of CQDs as the structure-directing agent for the assembly of functional micro/nanoelectrodes. Herein, we have developed a general, and simple strategy to fabricate 3D porous hierarchical carbon quantum dots (CQDs)/M x O y (M = Co, Ni) composite nanostructures from thermolysis of corresponding CQDs/M(OH) y , where CQDs play crucial role as a structure-directing agent in tuning the morphologies of the M(OH) y . With the merits of the large electroactive surface area, superior electronic conductivity of CQDs, and fruitful porous structure, the as-fabricated battery-type electrode materials present amazing supercapacitor performance. For example, the as-made porous hierarchical CQDs/Co 3 O 4 nanoarchitectures exhibited remarkable electrochemical performance with 1603 F g −1 at 1 A g −1 , excellent rate capacity of 70.6% from 1 to 100 A g −1 , superior cycling ability (97.0% capacity remained after 2000 cycles). Furthermore, the CQDs/Co 3 O 4 //AC hybrid supercapacitor (HSC) exhibits a high specific capacity of 210.4 F g −1 with 74.8 W h kg −1 . The present work can be enlarged for the design of other functional 3D hierarchical micro-nanostructures in the fields of energy storage, catalysis, and photo/electrocatalysis.
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