SOLID STATE SCIENCES
·
2021
·
IF 3.059
Hongliang Shen,Jia He,Xiaoqiang Shao,Qin Su,Donglin Zhao,Shaojie Feng
The modified ZnGa 2 O 4 microspheres were prepared by the conventional hydrothermal method and used to catalyze methane combustion reaction. Because Co 2+ and Zn 2+ have similar ion radii, so it seems that the Zn 2+ at the tetrahedral (T d ) position of ZnGa 2 O 4 was partially replaced by Co 2+ to adjust the oxygen distribution, and finally the Zn 1-x Co x Ga 2 O 4 (x = 0.1, 0.3) microspheres catalysts was obtained. X-ray photoelectron spectroscopy (XPS) analysis exhibited that Co 3+ were present in the Zn 1-x Co x Ga 2 O 4 (0.1, 0.3) samples, and interstitial oxygen were formed to maintain electrical neutrality. Oxygen temperature programmed desorption (O 2 -TPD) profiles showed that there was only one oxygen species desorption from ZnGa 2 O 4 sample, while the Zn 1-x Co x Ga 2 O 4 (0.1, 0.3) samples had two oxygen desorption peaks, that is the first one is surface adsorbed oxygen, the second is lattice oxygen. The catalytic methane combustion performance of the samples indicated that the partial substitution of Co 2+ for Zn 2+ in ZnGa 2 O 4 can effectively improve its activity.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Li Wang,Wende Hu,Zhou Shang,Xiaoming Cao,Yun Guo,Jiayi Li,Qiyuan Gu,Ke Li,Xiaobo Li
Enhancement in oxidation performance of Co 3 O 4 -based catalysts can be achieved by regulating K, and the promotion effects were strongly depended on the amount and existing state of K. Only the surface Co substituted by optimum amount of K (CoK 2 with K/Co mole ratio of 1.56 × 10 -2 ), unexpectedly high activities could be achieved. The specific activity of CoK 2 were 20 and 2.7 times higher than that of Co 3 O 4 for CO oxidation and CH 4 combustion. However, the excess K in the form of carbonate or nitrate deactivated the active sites, so the performance against K amount behaved as a volcano curve. Based upon the electronic and structural modification of K, the electron density of Co and O simultaneously decreased which weakened CO adsorption strength and improved the C H bond activation. Since efficiency in various pollutants removal, CoK 2 could be considered as a promising candidate for noble metal catalysts.
研究领域:
化学
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Chengxiang Huang,Zhou Jiang,Detian Meng,Xiujuan Li,Jianrong Zeng,Xiangyu Wu,Meiqi Liu,Kexin Song,Fuxi Liu,Aofei Wei,Longyu Guo,Taowen Dong,Meng Zou,Wei Zhang
NiMoO 4 (NM) has garnered significant attention due to its rich d -orbital electronic structure and multivalent electroactive cations. However, the inherently low electrical conductivity of NM limits its reaction kinetics. Herein, cobalt-substituted NM (Co-NM) nanorods were prepared via a hydrothermal reaction followed by subsequent thermal treatment. The incorporation of Ni-O-Co configurations stimulates an enhanced π -donation effect of the Co-O bond, facilitating the hybridization between the O 2 p and Co 3 d orbitals and thereby boosting charge transfer kinetics during electrochemical processes. The optimized 10 %Co-NM nanorods demonstrated a remarkable specific capacity of 557.8 C·g −1 at 1 A·g −1 . Furthermore, an asymmetric supercapacitor constructed with 10 %Co-NM as the positive electrode and FeOOH as the negative electrode, achieved a significant energy density of 63.58 Wh·kg −1 at a power density of 805.38 W·kg −1 . Thus, our work provides new insights into the rational design of stable bridging configurations to significantly improve electrochemical reaction kinetics.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2019
·
IF 2.781
Dongmei Zeng,Zhenhua Dan,Fengxiang Qin,Hui Chang
Cobalt alloying for Fe 83.3 Si 4 B 8 P 4 Cu 0.7 amorphous alloy can enhance the decolorization performances of azo dye wastewater. Co substitutions in amorphous Fe 83.3-x Co x Si 4 B 8 P 4 Cu 0.7 ( x = 0, 10, 20 and 40 at.%) alloys play a positive role in improving the decolarization efficiencies of methyl orange azo dyes (MO). Amorphous Fe 73.3 Co 10 Si 4 B 8 P 4 Cu 0.7 alloy has better abilities to break –N=N– bonds of MO than Fe 83.3 Si 4 B 8 P 4 Cu 0.7 , Fe 63.3 Co 20 Si 4 B 8 P 4 Cu 0.7 and Fe 43.3 Co 40 Si 4 B 8 P 4 Cu 0.7 alloys, and is able to degrade MO to mainly form sulfanilic acid anions with trace amounts of intermediate products with higher complete degrees. The rate determining step of MO degradation is the surface adsorption on amorphous Fe 43.3 Co 40 Si 4 B 8 P 4 Cu 0.7 alloy, and the intermediate degradation products with –N=N– bonds are dominantly formed with small amount of sulfanilic acid anions. The highest surface-area normalized rate constant ( k SA ) of MO degraded by Fe 73.3 Co 10 Si 4 B 8 P 4 Cu 0.7 ribbons is confirmed to be 0.69, 3 times higher than that of zero-valent Fe powders and Fe 83.3 Si 4 B 8 P 4 Cu 0.7 ribbons. The degradation pathways of MO by amorphous Fe 73.3 Co 10 Si 4 B 8 P 4 Cu 0.7 alloy different from those by Fe 83.3 Si 4 B 8 P 4 Cu 0.7 and Fe 43.3 Co 40 Si 4 B 8 P 4 Cu 0.7 alloys have been clarified on basis of the UV–Vis and HPLC-MS data. The experimental results manifest that the degradation performances are enhanced by Co substitutions due to the sharp decrease of reaction activation energies and the improvements of adsorption performances. The mechanism changes from reduction degradation to adsorption-determined degradation modes with increases of Co concentrations. MO degradations on amorphous Fe 73.3 Co 10 Si 4 B 8 P 4 Cu 0.7 alloy are governed by adsorption-enhanced reductive degradation mechanism.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
Magnetochemistry
·
2022
·Vol. 8
·期 8
·75
·
IF 3.336
Yujie Yang,Congliang Chen,Dongyang Chen,Yingming Zhang,Yuting Meng,Cong Zhang,Shuangjiu Feng
The solid-state reaction method is used to synthesize W-type Sr hexagonal ferrites Sr0.8Pr0.2(Zn1.0−xCox)2Fe16O27(x = 0.00, 0.15, 0.30, 0.45, 0.60, 0.75). The results of XRD for the W-type hexagonal ferrites, when Co content (x) is 0.00 ≤ x ≤ 0.75, exhibit that they are in the single W-type hexaferrite phase. As shown by morphological analysis, the particles are hexagonal-shaped platelets. The saturation magnetization (Ms) and magneton number (nB) increases with Co content (x) from 0.00 to 0.60.MsandnBbegins to decrease at Co content (x) ≥ 0.60. With increasing Co content (x) from 0.00 to 0.75, the magnetic anisotropy field (Ha), first anisotropy constant (K1), and coercivity (Hc) decrease gradually. The values of DC electrical resistivity for W-type hexagonal ferrites Sr0.8Pr0.2(Zn1.0−xCox)2Fe16O27(0.00 ≤ x ≤ 0.75) are in the range of 20.854 × 107Ω-cm and 22.755 × 107Ω-cm.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）