Nanomaterials
·
2019
·Vol. 9
·期 8
·1118
·
IF 4.034
Qiuwan Han,Dongyang Zhang,Jiuli Guo,Baolin Zhu,Weiping Huang,Shoumin Zhang
The gold catalysts supported on various morphologies of α-Fe2O3in carbon monoxide (CO) oxidation reaction have been studied for many researchers. However, how to improve the catalytic activity and thermal stability for CO oxidation is still important. In this work, an unusual morphology of α-Fe2O3was prepared by hydrothermal method and gold nanoparticles were supported using a deposition-precipitation method. Au/α-Fe2O3catalyst exhibited great activity for CO oxidation. The crystal structure and microstructure images of α-Fe2O3were carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and the size of gold nanoparticles was determined by transmission electron microscopy (TEM). X-ray photoelectron spectra (XPS) and Fourier transform infrared spectra (FTIR) results confirmed that the state of gold was metallic. The 1.86% Au/α-Fe2O3catalyst calcined at 300 °C had the best catalytic performance for CO oxidation reaction and the mechanism for CO oxidation reaction was also discussed. It is highly likely that the small size of gold nanoparticle, oxygen vacancies and active sites played the decisive roles in CO oxidation reaction.
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高影响因子
CHEMOSPHERE
·
2022
·
IF 8.943
Jun Cai,Yuanhang Ren,Yi Xia,Lei Tao,Xueqian Wang,Langlang Wang,Ping Ning,Yixing Ma
A cubic SrTiO 3 (STO) composite material co-doped with Ce and Cr ions was synthesized by solvothermal method . The fully characterized samples were employed as photocatalysts for the oxidation of Hg 0 . The co-doped samples afforded excellent catalytic removal efficiency of 98.99% using UV irradiation and 89.9% using visible light irradiation for Hg 0 compared with the single-doped samples. It was found that co-doped samples had a lower electron-hole recombination rate, largest Brunauer-Emmett-Teller specific surface area , and reduced band gap. The electron spin resonance results revealed that ·O 2 − and ·OH were the main active species in the catalytic process. Moreover, the co-doped samples exhibited the best electron transfer rate and the highest photocurrent response intensity. The electron transfer between the elements in the co-doped sample enables it to achieve stable and efficient catalytic performance. In addition, even after five consecutive catalytic runs, the co-doped sample maintained high catalytic activity . This work highlights the potential of the perovskite-type STO materials in the photocatalytic oxidation of gaseous mercury.
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高影响因子
COLLOID AND POLYMER SCIENCE
·
2023
·Vol. 301
·期 3
·175-187
·
IF 2.4
Meng Rui,Liu Liqin,Guo Weihong
A novel Al 2 O 3 –PDA–MoS 2 nanohybrid was synthesized by depositing Al 2 O 3 nanoparticles on the surface of molybdenum disulfide (MoS 2 ) sheets covered with polydopamine (PDA). Many characterizations demonstrated that the Al 2 O 3 was successfully deposited on the surface of MoS 2 . It was found that when the mass ratio of PDA–MoS 2 to Al 2 O 3 was 1.5:1, the nano-hybrid filler showed good dispersion performance. Then, the composite coating samples were prepared by adding Al 2 O 3 –PDA–MoS 2 (1.5:1) hybrid to waterborne epoxy resin. The effects of Al 2 O 3 , MoS 2 , and PDA–MoS 2 on the corrosion resistance of epoxy coating were also investigated. The potentiodynamic polarization test demonstrated that Al 2 O 3 –PDA–MoS 2 nanohybrids had excellent corrosion inhibition properties. The results of electrochemical impedance spectroscopy also revealed that the impedance modulus of Al 2 O 3 –PDA–MoS 2 /EP composite coating was nearly two orders of magnitude higher than that of pure epoxy resin after immersion in saline for 21 days. This study confirmed that Al 2 O 3 –PDA–MoS 2 nanosheets had better barrier properties and corrosion inhibition properties, and provided a new idea for the wide application of nanofillers in the field of anticorrosion.
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高影响因子
Molecular Catalysis
·
2018
·
IF 0
Liangliang Zhang,Xiao Chen,Zhijian Peng,Changhai Liang
Chemoselective hydrogenation of C C and C O bonds in the cinnamaldehyde (CMA), was successfully performed with highly dispersed transition metal silicides-embedded in the porous carbon matrix (M 2 Si@C (M = Fe, Co, Ni)) nanocatalysts with a particle size of 8–12 nm, which were synthesized by a facile approach via microwave-assisted chemical vapor deposition (MWCVD) using organosilane and metal-organic-framework (MOFs-74)-templated porous carbon matrix-encapsulated transition metal (M@C) precursors. Compared with M@C, the activity of M 2 Si@C (M = Fe, Co, Ni) nanocatalysts obviously increases, which can be attributed that the overlayered carbon on metals has been destroyed during MWCVD processing, leading to the exposure of more active sites of catalysts. Due to the inherent electronic properties of metallic active sites in the metal silicides, the catalytic activity of Ni 2 Si@C was much higher than that of Co 2 Si@C and Fe 2 Si@C in the chemoselective hydrogenation of CMA. At total conversion of CMA, the Co 2 Si@C nanocatalyst was chemoselective for the hydrogenation of polar C O bonds (selectivity to cinnamyl alcohol of ∼60%), whereas Ni 2 Si@C nanocatalyst was highly chemoselective for the hydrogenation of non-polar C C bonds (selectivity to hydrocinnamaldehyde of ∼90%). The doping of silicon atoms with more electropositive into metals lattices in the M-Si intermetallic compounds (IMCs) influenced the adsorption of substrate molecule on the catalyst surface, slightly leading to the different reaction routes. In addition, the Co 2 Si@C and Ni 2 Si@C respectively maintain the robust stability in the hydrogenation of CMA. This result provided guidance on the design of catalyst via tuning the polarization properties of the inter-atoms in the IMCs according to the target product.
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JOURNAL OF NON-CRYSTALLINE SOLIDS
·
2023
·
IF 3.5
Yinghui Shi,Minghui Zhang,Kun Chen,Weijie Deng,Xuechao Liu,Huirong Su,Jiansheng Xie,Xiangyuan Wang,Jiabao Wan,Haibo Wang
A modified melt quenching technique was used to prepare new Tm 3+ /Ho 3+ co-doped TeO 2 -Ta 2 O 5 -La 2 O 3 (TTL) glass with high emission cross section . By standing the traditional tube furnace sideways, the melt quenching method is optimized to produce tellurate glass efficiently and simply. The performance of the glass system is studied in detail, and the possibility of this glass system as a 2.0 μm fiber laser material is obtained. The glass system was obtained by test analysis to have large refractive index (n d >2.01) and density (>5.28 g/cm 3 ), excellent mechanical properties (>4.5Gpa). TTL5 glass was obtained with excellent glass transition temperature (Tg>439 °C) and good resistance to crystallization based on thermodynamic analysis(ΔT>170 °C). In addition, the bonding structure was studied and maximum phonon energy of TTL5 glasses was determined to be ∼669 cm −1 by Raman. The SEM micrographs show well the surface micromorphology of TTL3 and TTL5, and EDAX verifies that the results of elemental analysis of this system of glasses are reliable. Fluorescence spectroscopy demonstrated a TTL5 series of samples with 2.0 μm strong emission. Finally, the absorption emission cross-sections of Ho 3+ were calculated to be as high as7.92×10 −21 (at 1963 nm) and 12.301×10 −21 (at 2061 nm), respectively, with a maximum gain factor of 2.75 cm −1 . The results show that this new TTL series glass has high thermal stability, low phonon energy, and efficient 2.0 µm fluorescence, extending the tellurite glass system and being a good candidate for obtaining efficient 2.0 µm emission.
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高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2023
·
IF 3.3
Jun Sun,Bei Zhang,Wei Zhu,Feifei Huang,Ruoshan Lei,Hongping Ma,Renguang Ye,Youjie Hua,Shiqing Xu
High-efficiency phosphor with excellent luminescence properties and thermal stabilities is essential for phosphor-converted white light-emitting diodes (w-LEDs). Compared with red and green phosphors, near-ultraviolet excited blue phosphors with high efficiency and excellent thermal stability are still scarce, and the development of efficient blue phosphors remains challenging. NaLi 3 SiO 4 : Eu 2+ (NLSO: Eu 2+ ) is a promising narrow-band blue phosphor. In this paper, a series of Na 1-y K y Li 3 SiO 4 : 5%Eu 2+ (0.05 ≤ y ≤ 0.2) phosphors were successfully synthesized by high-temperature solid-state reaction through co-doping a small amount of K + ions in the matrix, significantly improving their luminescence property and thermal stability. Because of the weaker electronegativity of K + ions, the emission peaks of Na 1-y K y Li 3 SiO 4 : 5%Eu 2+ were slightly blue-shifted from 467 to 463 nm compared with those of NLSO: Eu 2+ . With an increase in the number of K + ions, the luminescence intensity of the phosphors increased. When the content of the K + ion reached 0.2, the luminescence intensity of the Na 0.8 K 0.2 Li 3 SiO 4 : 5%Eu 2+ (NKLSO: 5%Eu 2+ ) phosphor reached its maximum. Compared to the NLSO: 5%Eu 2+ phosphor, the luminescence intensity increased by approximately 300 %. At 150 °C, the luminescence intensity of NLSO: 5%Eu 2+ phosphor was retained at 75.98 % compared with room temperature , while the NKLSO: 5%Eu 2+ phosphor maintained a luminescence intensity of 84.36 % relative to room temperature, demonstrating excellent thermal stability. The enhanced luminescence performance of the NKLSO: Eu 2+ phosphor makes it a promising high-efficiency blue phosphor for phosphor-converted w-LEDs.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Zengpeng Li,Jianfeng Dai,Danqiang Huang,XinChao Wen
BiFeO 3 –(Co/Ni)Fe 2 O 4 (BFO–(C/N)FO) multiferroic nanofibers were synthesized using a self-assembly coaxial electrospinning technique . The structure, exchange bias effect, ferromagnetic, and ferroelectric properties were investigated using various physical and chemical characterization approaches. The coexistence of a spinel–perovskite mixed structure was verified in (BFO–(C/N)FO) nanofibers by X-ray diffraction and X-ray photoelectron spectroscopy . Raman spectra revealed a distorted crystal structure or more complex phase configurations with overlapping features. Compared to the pure BFO nanofibers, the magnetic properties showed a significantly increase after recombination. BFO–NFO nanofibers exhibited higher exchange coupling through switching field distribution analysis. The ferroelectric properties of the composite nanofibers were considerably changed compared to pure BFO nanofibers, which can be attributed to the presence of impurities (Bi 2 Fe 4 O 9 ) and the asymmetrical spin in spinel ferrites. The BFO–CFO nanofibers exhibited larger leakage current and coercive electric field than the other two types of nanofibers. Hence, coupling of the structural distortion and crystal phases are important approaches in altering the ferroelectric and ferromagnetic properties. These results suggest that the BFO–(C/N)FO nanofibers have potential applications in multifunctional nanodevices .
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2017
·
IF 9.446
Lu Jiang,Shuang Ni,Gang Liu,Xiaoxiang Xu
In this work, we have applied Cr/Nb co-doping strategy to the wide band gap semiconductor Bi 3 TiNbO 9 and have performed a detailed investigation on the structure, optical and photocatalytic properties of these modified Aurivillius compounds Bi 3 Ti 1-2x Cr x Nb 1+x O 9 (x = 0, 0.1, 0.2, 0.3). Our results suggest that Cr/Nb doping slightly expand the unit cell of Bi 3 TiNbO 9 with a doping limit around 20%. The involvement of Cr/Nb dopants in the crystal structure significantly reduces the band gap of Bi 3 TiNbO 9 by nearly 1 eV. Photocatalytic experiments and photoelectrochemical measurements confirms the critical role of Cr/Nb dopants in improving photocatalytic hydrogen production and anodic photocurrent. More than two-fold enhancement in hydrogen production has been noticed for merely 10% Cr/Nb co-doping. The highest photocatalytic activity belongs to Bi 3 Ti 0.8 Cr 0.1 Nb 1.1 O 9 (x = 0.1) for full range illumination and to Bi 3 Ti 0.6 Cr 0.2 Nb 1.2 O 9 (x = 0.2) for visible light illumination, with apparent quantum efficiency (AQE) approaching 0.52% and 0.27%, respectively. DFT calculation discloses the role of Cr in forming a new valence band inside the band gap of Bi 3 TiNbO 9 . In addition, strong anisotropic phenomenon in charge transportation of Bi 3 TiNbO 9 is also verified by DFT, as both conduction band minimum (CBM) and valence band maximum (VBM) are buried in the [BiTiNbO 7 ] 2− perovskite slabs and charges are only allowed to migrate within the slabs.
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高影响因子
JOURNAL OF LUMINESCENCE
·
2021
·
IF 3.599
Yanting Zhu,Chenxia Li,Degang Deng,Hua Yu,Hao Li,Le Wang,Changyu Shen,Xufeng Jing,Shiqing Xu
A series of Eu 2+ /Cr 3+ co-doped BaAl 12 O 19 phosphor was synthesized by traditional high temperature solid stated method, and the temperature-sensitive characteristic of the phosphor was researched. Due to the temperature sensitivity of the fluorescence lifetime of Cr 3+ , the thermometry based on fluorescence lifetime can be realized. Furthermore, the emissions of Eu 2+ ion and Cr 3+ ion can be well separated, which shows the excellent signal recognition ability of this phosphor. The Eu 2+ /Cr 3+ co-doped BaAl 12 O 19 phosphor can be used for the thermometry based on fluorescence intensity ratio. A dual-mode optical thermometry is proposed and researched in the temperature range of 293–563 K by using the decay lifetime of Cr 3+ emission and in the temperature range of 295–476 K by using the fluorescence intensity ratio of Eu 2+ to Cr 3+ as temperature readout. The maximum values of relative sensitivity are 0.466% K −1 at 363 K and 0.259% K −1 at 476 K. The Eu 2+ /Cr 3+ co-doped BaAl 12 O 19 phosphor has excellent optical temperature characteristic , and its dual-mode thermometry characteristics provide convenience for the application of this material. This phosphor has potential application prospects in the field of optical thermometry.
研究领域:
材料科学
·
光学工程
·
无机化学
·
传感器技术
·
功能材料
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DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2019
·
IF 6.361
Kai-Wen Cao,Hao Huang,Fu-Min Li,Hong-Chang Yao,Juan Bai,Pei Chen,Pu-Jun Jin,Zi-Wei Deng,Jing-Hui Zeng,Yu Chen
The reactive and stable catalysts for the oxygen reduction reaction are highly desirable for low temperature fuel cells. The commercial oxygen reduction reaction electrocatalysts generally reply on noble metal based nanomaterials, which suffer from inherent cost and selectivity issues. At present, it still remains challenge for designing efficient non-noble metal-based oxygen reduction reaction electrocatalysts. Herein, we successfully synthesize Co nanoparticles supported on three-dimensionally N-doped holey graphene aerogels hybrids by the high-temperature calcination of the graphene aerogels-polyallylamine-Co II hybrids. The component optimized hybrids show the excellent electrocatalytic activity for oxygen reduction reaction in alkaline media, which is comparable to commercial Pt/C electrocatalyst. Meanwhile, the hybrids also show eminent tolerance for CO and methanol, attributing to their excellent oxygen reduction reaction selectivity. The three-dimensionally interconnected structure of graphene aerogels, N-doping, uniform dispersion and high crystallinity of Co nanoparticles, and holey structure of graphene contribute to the striking oxygen reduction reaction activity of hybrids.
研究领域:
材料科学
·
电化学
·
纳米催化
·
能源材料
·
燃料电池
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DOI
高影响因子
THERMOCHIMICA ACTA
·
2016
·
IF 1.938
Lipeng Wang,Fucheng Zhang,Yongping Bai,Liping Ding
The kinetic of non-isothermal crystallization of Poly (ethylene terephthalate-co-sodium-5-sulfo- iso -phthalate) (PETI) was investigated using differential scanning calorimetry (DSC). Various macrokinetic models namely the Avrami, Tobin, Ozawa, and Ziabicki were used to describe the non-isothermal crystallization process of PETI. Both of the Avrami crystallization rate constant and the Tobin crystallization rate constant were observed to increase with increasing cooling rate. The Avrami model is better than the Tobin model to describe the non-isothermal crystallization process of PETI. The Ozawa crystallization rate K O was found to decrease with increasing cooling rate, while Ziabicki’s kinetic crystallizability parameter G Z was found to increase with increasing cooling rate. The effective energy barrier △E for non-isothermal crystallization process of PETI, analyzed based on the differential iso-conversional method of Friedman, was found to be an increasing function of the relative crystallinity.
研究领域:
高分子化学
·
材料科学
·
物理化学
·
热分析
·
聚合物结晶
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DOI
高影响因子
OPTICAL MATERIALS
·
2020
·
IF 2.779
Hua Yu,Fengping Ruan,Leifeng Chen,Degang Deng
Ca 9 Zn 1.5 (PO 4 ) 7 : Eu 2+ /Eu 3+ phosphors had been synthesized via conventional high temperature solid-state reaction. Based on the different thermal quenching characteristics between 4f-5d transition of Eu 2+ ions and 4f-4f transition of Eu 3+ ions, the fluorescence intensity ratio (FIR) of Eu 3+ to Eu 2+ exhibits temperature dependence at the temperature from 293 to 473 K. The maximum absolute and relative temperature sensitivity of Ca 9 Zn 1.5 (PO 4 ) 7 : Eu phosphor can reach up to 0.0034 K −1 and 1.4% K −1 at 453 K, respectively, when used as thermometric material. These results indicated that our study opens up an effective approach for developing other high-performance self-calibrated optical thermometers.
研究领域:
材料科学
·
光学传感器
·
发光材料
·
测温技术
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DOI
高影响因子
危险品化学品经营许可证（带存储）