JOURNAL OF SOLID STATE CHEMISTRY
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2025
·
IF 3.5
Jing Yang,Yun Zhang,Xiaoning Li,Xinghua Zhu,Shihua Ding,Wenjie Zhou,Tianxiu Song
BaSi 2- x Al x O 5- x /2 ( x = 0-0.05) low-dielectric ceramics were prepared by the solid-phase method. The effects of heterovalent ion substitution on the crystal structure and microwave dielectric properties were studied. X-ray (XRD) diffraction revealed that they formed single-phase solid solution with orthorhombic structure. Appropriate amount of Al 3+ doping decreased the sintering temperature from 1225 °C to 1150 °C. The change in dielectric constant ( ε r ) resulted from the combined effects of the ionic nature of chemical bonds ( f i ave ) (internal factor) and the relative density (external factor). Si-O bonds contributed more significantly to the ceramic dielectric polarization. The increase in packing density and lattice energy ( U Total ) enhanced the quality factor ( Q×f ), which nearly tripled compared with the undoped case. The resonant frequency temperature coefficient ( τ ƒ ) was dominated by oxygen bond valence ( V o ). When sintered at 1150 °C for 4 h, BaSi 1.98 Al 0.02 O 4.99 exhibited optimal performance: ε r = 7.56, Q×f = 41,878 GHz, τ f = -17.65 ppm/°C. This study offered a new approach to modifying BaSi 2 O 5 ceramics.
研究领域:
材料科学
·
化学
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高影响因子
ACS Applied Engineering Materials
·
2025
·
IF 3.5
Yazhou Shuang,Fang Wang,Weihao Zhao,Hongkang Wang,Zelin Ma,Jie Jian,Shiyuan Wang,Jiulong Wang,Longyang Li,Pengfei Guo,Qian Ye,Fei Xu,Hongqiang Wang
Vanadium oxide (VOx)-based catalysts for propane (C3H8) dehydrogenation (PDH) demonstrate excellent redox properties due to the multivalent property of vanadium; however, the unsatisfactory catalytic efficiency and recondite catalytic mechanisms seriously restrict their widespread applications. Herein, we proposed the doping of cobalt oxide (CoOx) species into VOx supported on alumina for simultaneously facilitating the catalytic performance in PDH with (oxidative) and without CO2 (nonoxidative). The CoOx-doped VOx species are uniformly impregnated onto alumina supports through a ligand-free wet chemical impregnation method, without any additives. The results show that the CoOx doping modulates the electronic interactions between VOx species, thus increasing the reductive capability of the catalyst and mitigating the competitive absorption of CO2 with C3H8. Consequently, superior catalytic performances are achieved in both nonoxidative and CO2-oxidative PDH reactions compared to pristine VOx species without CoOx doping. Otherwise, the dry reforming of C3H8 is significantly inhibited compared to pristine CoOx species without VOx doping. Notably, a higher and impressive conversion rate up to 55.5% for target products (C3H6) is achieved in nonoxidative PDH compared to CO2-oxidative PDH on the CoOx-doped VOx catalyst, indicative of the competitive adsorption between reactants (CO2 and C3H8) during the catalytic process. This study provides a forward-looking mechanism to establish separate reaction pathways for each reactant (CO2 and C3H8) to improve mass transfer, thereby enhancing the efficiency of CO2-oxidative PDH.
研究领域:
催化化学
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化学工程
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材料科学
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能量转换
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多相催化
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高影响因子
CRYSTENGCOMM
·
2025
·Vol. 27
·期 19
·3134-3142
·
IF 2.6
Yikun Zhang,Pan Hu,Yongfu Liu,Jianfeng Sun,Jun Jiang
Al2O3:Cr3+ ruby is one of the most popular materials for lasers because it has unique optical and physical properties. How to obtain Al2O3:Cr3+ efficiently and economically remains a challenge. In this study, Al2O3:Cr3+ transparent ceramics were prepared through a traditional solid-state process in a vacuum environment. A high transmittance of 76.8% at 1200 nm, approaching that of single crystals, can be reached in the pure Al2O3 transparent ceramic. The photoluminescence, micromorphology, thermal conductivity, and mechanical characteristics of Al2O3:Cr3+ transparent ceramics were studied. A ruby with a thermal conductivity of about 38 W m−1 K−1 and a high hardness of 1859 HV was prepared. These results indicate that Al2O3:Cr3+ transparent ceramics have broad prospects to serve as a substitute for Al2O3:Cr3+ single crystals in certain fields.
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APPLIED CATALYSIS A-GENERAL
·
2017
·
IF 4.339
Miaomiao Liu,Weiqiang Tang,Yisheng Xu,Hongbo Yu,Hongfeng Yin,Shuangliang Zhao,Shenghu Zhou
Pd-SnO 2 heteroaggregate nanocatalysts were synthesized by in-situ transformation of PdSn bimetallic nanoparticles on alumina. The PdSn bimetallic nanoparticles were prepared by co-reduction of Pd and Sn precursors. The obtained PdSn nanoparticles possibly have a core-shell like structure with Pd cores and Sn-rich shells due to the fast reduction of Pd precursors. The Pd-SnO 2 /Al 2 O 3 heteroaggreagte nanocatalysts were synthesized by calcination of PdSn/Al 2 O 3 in air followed by H 2 reduction. Various characterization techniques, such as HRTEM, XRD and XPS, were used to characterize the PdSn and Pd-SnO 2 . The Pd 3 -(SnO 2 ) 1 /Al 2 O 3 heteroaggreagte nanocatalysts with a ratio of Pd/Sn of 3/1 illustrated enhanced catalytic performances for p -nitroacetophenone and p -nitrobenzaldehyde hydrogenations relative to monometallic Pd nanocatalysts. Theoretical calculations using density functional theory suggested that Pd-SnO 2 facilitates the adsorption of reactants in a higher degree than that of products, thus enhancing the catalytic activity even with partial coverage of Pd surfaces with SnO 2 . The blockage effect of SnO 2 on Pd surfaces is speculated to enhance the catalytic selectivity for p -nitroacetophenone and p -nitrobenzaldehyde hydrogenations over Pd-SnO 2 heteroaggregate nanocatalysts.
研究领域:
催化化学
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材料科学
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理论计算
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高影响因子
MATERIALS & DESIGN
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2016
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IF 3.997
Yuandong Peng,Yi Yi,Liya Li,Jianhong Yi,Junwu Nie,Chongxi Bao
The alumina sol was obtained using Al(C 3 H 7 O) 3 as a precursor. Pure Fe particles were coated with Al 2 O 3 using a sol–gel method and subsequently calcinated at 1100 °C. The resulting soft magnetic composites were investigated while varying the treating temperature. Scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analyses revealed that the surface of the Fe powder particles comprised a thin α-Al 2 O 3 insulating layer uniformly distributed after calcination at 1100 °C for 1 h. The permeability increased with the treating temperature, reaching a stable value of 93 from 675 °C to 725 °C. The hysteresis losses decreased, whereas the eddy losses increased with the treating temperature in the range of 650–725 °C. The core losses ( P cv ) decreased (lowest value: 10.2 kW/m 3 ) up to 675 °C and increased thereafter. The permeability of the material annealed at 675 °C remained stable with changes in the frequency, whereas P cv remained low over the 5–100 kHz range. A noticeable insulation layer separating the different Fe particles was observed by SEM for the samples annealed below 700 °C.
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高影响因子
Desalination and Water Treatment
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2024
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IF 1
Wenquan Sun,Biao Ma,Yongjun Sun,Huaili Zheng,Genchao Ma
In this work, the degradation of tetracycline (TC) in wastewater was investigated using the γ-Al 2 O 3 – Bi–(Sn/Sb) particle electrodes. Parameters affecting the degradation efficiency and energy consumption of the γ-Al 2 O 3 –Bi–(Sn/Sb) particle electrodes, such as electrical conductivity, initial pH, air flow, current intensity, plate distance, filling ratio, and initial wastewater concentration, were systematically investigated. Results showed that the optimal conditions were 4000 mS·cm - 1 conductivity, pH 6, 15 mL·min - 1 air flow, 0.1 A current intensity, 4 cm plate distance, 0.05 g·mL - 1 filling ratio, and 100 mg·L -1 wastewater concentration. More than 90% and 70% of TC and total organic carbon were degraded, respectively, under the optimal conditions. In addition, the γ-Al 2 O 3 –Bi–(Sn/Sb) particle electrodes had good stability and reproducibility.
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高影响因子
SOLAR ENERGY
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2017
·
IF 4.018
Shuangshuang Liu,Kun Cao,Hao Li,Jinkui Song,Junbo Han,Yan Shen,Mingkui Wang
In this research work, for the first time, we introduced thin composite films (∼1.8 μm) made with NiO nanoparticles and single-walled carbon nanotubes (SWCNT) as alternatives to replace the commonly used carbon black/graphite counter electrode in full printable organic hole-transport layer free mesoporous perovskite solar cells. Due to the relative thick carbon black/graphite counter electrodes, which are typically ∼10 μm thick, charge collection and batch to batch reproducibility of this type devices are significantly limited. We find an appreciated power conversion efficiency of 12.7% can be achieved for the CH 3 NH 3 PbI 3 perovskite solar cell using mesoscopic TiO 2 /Al 2 O 3 framework structure in combination with a thin NiO/SWCNT counter electrode under standard reporting conditions. Electronic impedance spectroscopy measurements reveal efficient charge collection ability for perovskite devices using thin NiO/SWCNT counter electrodes compared to the conventional carbon black/graphite counter electrode, and thus can efficiently deliver photocurrent.
研究领域:
光伏技术
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材料科学
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纳米技术
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可再生能源
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太阳能电池
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2026
·Vol. 61
·期 12
·7950-7967
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IF 4.4
Feng Changjian,Yang Hongkai,Huang Lilan,Lv Lin,Li Jiao
In this study, a La-doped flexible hydrophobic Al 2 O 3 fiber membrane was fabricated via electrospinning technology, and the influence of La doping on the mechanical properties and surface wettability of the Al 2 O 3 fiber membrane was systematically investigated. The results showed that the La-doped modified alumina nanofiber membrane has tunable fiber diameters (180–480 nm) and a highly interconnected porous network, which enhanced the efficiency and flux of oil–water separation. The incorporating an appropriate amount of rare earth La atoms, specifically at a La/Al atomic ratio of 0.125 (La-Al 2 O 3 -2), effectively enhanced the flexibility and tensile strength of the membrane. Concurrently, hydrophobic La 2 O 3 formed on the fiber surface, which transformed the membrane from hydrophilic to hydrophobic. As a result, the La-doped Al 2 O 3 membrane exhibited excellent anti-fouling performance, high permeation flux, and efficient oil–water separation. However, excessive La addition led to a significant decline in the flexibility and tensile strength of the Al 2 O 3 fiber membrane, whereas the hydrophobic surface was largely preserved. Among all samples, the La-Al 2 O 3 -2 fiber membrane exhibited superior flexibility and tensile strength. In oil–water separation applications, it achieved a high permeation flux of 2921 L/(m 2 ·h) and a separation efficiency of 98.4%; meanwhile, the good reusability was also obtained. Graphical abstract
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高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Yanzhao Gao,Xianglei Meng,Shiqi Huang,Hui Wu,Liantao Jiang,Yu Zhou,Yuting Song,Yanyan Diao
Gamma alumina is widely utilized for preparing the supported noble metal catalysts for the hydrogenation reaction. It is an effective strategy to improve the catalytic performance of catalysts via modifying gamma alumina with alkaline earth metal to regulate its surface acidity and electronic properties. Herein, Pd catalysts supported by Al 2 O 3 and Mg-modified Al 2 O 3 are synthesized via the wet impregnation method, and the effects of MgO doping on the structure, composition, and surface acidity of Pd/γ-Al 2 O 3 catalysts are investigated via X-ray diffraction patterns (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Temperature programmed desorption (TPD). The results show that Pd/MgO-Al 2 O 3 –2 (γ-Al 2 O 3 modified with 2 wt% Mg) has more metallic state palladium and weak acid sites and exhibits the best catalytic performance for the hydrogenation of perfluoro-4-methyl-2-pentene (D1). Density functional theory (DFT) calculations on Pd/Al 2 O 3 and Pd/MgO-Al 2 O 3 –2 catalysts are also performed to further explore the mechanism of D1 hydrogenation. The studies for Gibbs free energy of the potential reaction steps and intermediates reveal a complex process to generate the target product C 6 F 12 H 2 , and the rate-determining-step is the addition of the first hydrogen on the second carbon of perfluoro-4-methyl-2-pentene molecule.
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高影响因子
Journal of Materials Research and Technology-JMR&T
·
2023
·
IF 6.4
Hanjing Zhu,Meng Zhou,Ke Jing,Baohong Tian,Yi Zhang,Xu Li,Yunzhang Li,Xianhua Zheng,Heng Li,Zipeng Ma,Yong Liu,Alex A. Volinsky,Jin Zou
The 0.5Y 2 O 3 /Al 2 O 3 -Cu/30Mo3SiC and 0.3GO-0.5Y 2 O 3 /Al 2 O 3 -Cu/30Mo3SiC composites were fabricated by fast hot press sintering. Hot compression tests of the composites were carried out using the Gleeble-1500 simulator at 0.001–10 s −1 strain rates and 650–950 °C deformation temperatures. The effects of doped reduced graphene oxide (rGO) on the hot deformation behavior and microstructure of 0.5Y 2 O 3 /Al 2 O 3 -Cu/30Mo3SiC composites were investigated. Trace of molybdenum carbide (MoC) layers/nanoparticles formed in-situ at the rGO-Cu/Mo interface, which is beneficial to the interfacial bonding of the composite. The enhanced flow stress and activation energy of hot deformation is attributed to the addition of the rGO. The activation energy of the composites was improved by 11% with the addition of rGO. The dislocation density and texture orientation ratio decrease at higher deformation temperatures.
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高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Chuang-Tian Zhan,Jin-Yuan Wu,Kun-Heng Huang,Yun Li,Li-Xiang Wu,Sheng-Jin He,Yang-Qing Liu,Ze-Xi Zhang,Wei-Ming Guo,Jia-Xiang Xue,Hua-Tay Lin
The pressureless-sintered silicon carbide ceramic with and without surface texturing was joined with CaO-Al 2 O 3 -MgO-TiO 2 -SiO 2 glass filler. The experimental results showed that without texturing applied to SiC substrates, the shear strength of SiC joints was 40.8 ± 6.3 MPa, with failure occurring at the interlayer. Unfilled regions in the interlayer limited the shear strength of the joints. When texturing was applied to SiC substrates, SiO 2 layer was formed on the surface of substrates due to high-temperature oxidation, which subsequently promoted the wettability of filler on substrates. The textured grooves on SiC substrates could be filled with glass material during joining process. The shear strength of textured SiC joints was 69.3 ± 9.9 MPa with a mixed-mode failure when the direction of shear load was perpendicular to the texturing direction. The better wettability, larger joining area, and interlocking structure between the glass filler and substrates enhanced the shear strength of textured joints.
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高影响因子
Coatings
·
2023
·Vol. 13
·期 7
·1266
·
IF 3.4
Qian Kou,Weiliang Jin,Chuntao Ge,Jie Pang,Jun Zhang,Geir Martin Haarberg,Saijun Xiao,Ping Wang
In this paper, electrodeposition of a molybdenum coating was conducted in Na3AlF6-NaF-Al2O3-MoO3molten salts at 930 °C to investigate the availability of preparation of thick molybdenum coatings. The effects of current density and electrodeposition time on the morphology of the produced molybdenum coating were studied. With the increase of current density (10~70 mA·cm−2), the coating thickness was increased from 10 μm to 30 μm, with all the current efficiency above 97%. Under a current density of 30 mA/cm2, with the rise of electrodeposition time (10~60 min), three stages of the deposit growth were observed, including the formation of a large number of fine crystals, transformation into fibrous morphology and well-developed faceted grains. The formation of a large number of fine crystals at the initial stage of the electrodeposition could facilitate electroplating molybdenum coatings with good quality at higher current density and longer duration. Thus electrodeposition at a current density of 100 mA·cm−2for 3 h has been performed, resulting in the preparation of relatively flat, dense, and coherent molybdenum coatings with a thickness of 140 μm on a nickel substrate, with a current efficiency above 85%. It is anticipated that the electrodeposition of molybdenum coatings in the present molten system is suitable for electroplating thick molybdenum coatings.Keywords:cryolite-based molten salt;electrodeposition;molybdenum coating;nickel substrate
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高影响因子
危险品化学品经营许可证（带存储）