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Qi Yang Qilong Wu Yang Liu Shuiping Luo Xiaotong Wu Xixia Zhao Haiyuan Zou Baihua Long Wen Chen Yujia Liao Lanxi Li Pei Kang Shen Lele Duan Zewei Quan 《Advanced materials (Deerfield Beach, Fla.)》2020,32(36):2002822
Engineering novel Sn-based bimetallic materials could provide intriguing catalytic properties to boost the electrochemical CO2 reduction. Herein, the first synthesis of homogeneous Sn1−xBix alloy nanoparticles (x up to 0.20) with native Bi-doped amorphous SnOx shells for efficient CO2 reduction is reported. The Bi-SnOx nanoshells boost the production of formate with high Faradaic efficiencies (>90%) over a wide potential window (−0.67 to −0.92 V vs RHE) with low overpotentials, outperforming current tin oxide catalysts. The state-of-the-art Bi-SnOx nanoshells derived from Sn0.80Bi0.20 alloy nanoparticles exhibit a great partial current density of 74.6 mA cm−2 and high Faradaic efficiency of 95.8%. The detailed electrocatalytic analyses and corresponding density functional theory calculations simultaneously reveal that the incorporation of Bi atoms into Sn species facilitates formate production by suppressing the formation of H2 and CO. 相似文献
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《International Journal of Hydrogen Energy》2020,45(53):28860-28869
Developing highly active, stable and sustainable electrocatalysts for overall water splitting is of great importance to generate renewable H2 for fuel cells. Herein, we report the synthesis of electrocatalytically active, nickel foam-supported, spherical core-shell Fe-poly(tetraphenylporphyrin)/Ni-poly(tetraphenylporphyrin) microparticles (FeTPP@NiTPP/NF). We also show that FeTPP@NiTPP/NF exhibits efficient bifunctional electrocatalytic properties toward both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). Electrochemical tests in KOH solution (1 M) reveal that FeTPP@NiTPP/NF electrocatalyzes the OER with 100 mA cm−2 at an overpotential of 302 mV and the HER with 10 mA cm−2 at an overpotential of 170 mV. Notably also, its catalytic performance for OER is better than that of RuO2, the benchmark OER catalyst. Although its catalytic activity for HER is slightly lower than that of Pt/C (the benchmark HER electrocatalyst), it shows greater stability than the latter during the reaction. The material also exhibits electrocatalytic activity for overall water splitting reaction at a current density of 10 mA cm−2 with a cell voltage of 1.58 V, along with a good recovery property. Additionally, the work demonstrates a new synthetic strategy to an efficient, noble metal-free-coordinated covalent organic framework (COF)-based, bifunctional electrocatalyst for water splitting. 相似文献
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从退火态原位TiCp/Fe复合材料的切削力和切屑形状方面分析了其切削性能。研究结果表明其切削力及切削力的波动范围都小于铸态45钢,其切削性能比45钢好。TiCp/Fe复合材料的切屑为C形屑、长紧卷屑和发条状卷屑,在机加工中,产生这几种切屑是比较理想的。从切屑方面看,TiCp/Fe复合材料的切削性能较好。 相似文献
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《Hydrometallurgy》2006,81(3-4):234-240
The oxidation of glucose during the reductive leaching of pure MnO2 and manganese ore in sulphuric acid at 90 °C MnO2 was investigated. The aim was to identify the derivatives and the chemical pathway of glucose oxidation. Organic derivatives were monitored by HPLC using an Aminex HPX-78H column and UV detection. Chromatographic patterns of leaching solutions showed that major compound formed was formic acid. Minor quantities of glycolic, glyceric and traces of gluconic acids were identified. Results suggest that during the leaching reaction, the carbon chain of glucose is shortened by detachment of one carbon atom as formic acid. 相似文献
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《Intermetallics》2007,15(12):1497-1503
The coherent precipitate γ1-Ti4Nb3Al9 in the Nb-modified TiAl-based intermetallic compound with a nominal composition of Ti–48 at% Al–10 at% Nb was investigated by transmission electron microscopy. The crystallographic and morphologic characteristics of the precipitating phase have been calculated based on invariant line theory. It is revealed that in the γ-TiAl(Nb)/γ1-Ti4Nb3Al9 couples, both the morphological and crystallographical characteristics of the precipitate γ1-Ti4Nb3Al9 could be predicted by the three-dimensional phase transformation invariant line model. The needle direction of [001] at the early stage for coherent precipitate γ1-Ti4Nb3Al9 and [111] for equilibrium phase γ1-Ti4Nb3Al9 have both been explained well. The characterization of morphology and crystallography of the precipitate reaction in γ-TiAl/γ1-Ti4Nb3Al9 system sustain the postulate that precipitates are bounded by unrotated planes (eigenplanes) when three real eigenvalues exist. 相似文献
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特征选择有助于增强集成分类器成员间的随机差异性,从而提高泛化精度。研究了随机子空间法(RandomSub-space)和旋转森林法(RotationForest)两种基于特征选择的集成分类器构造算法,分析讨论了两算法特征选择的方式与随机差异程度之间的关系。通过对UCI数据集引入噪声,比较两者在噪声环境下的分类精度。实验结果表明:当噪声增加及特征关联度下降时,基本学习算法及噪声程度对集成效果均有影响,当噪声增强到一定程度后。集成效果和单分类器的性能趋于一致。 相似文献