Reacting the Unreactive: A Toolbox of Low-Temperature Solution-Mediated Reactions for the Facile Interconversion of Nanocrystalline Intermetallic Compounds
摘要:
Metallurgical materials, including intermetallic compounds, are notoriously inert toward low-temperature reactivity. However, as nanocrystals, their reactivity is significantly enhanced. Here we show that intermetallic PtSn and AuCu nanocrystals can be converted, in solution at low temperatures, into derivative intermetallics. For example, PtSn can be converted into PtSn2 and Pt3Sn by reaction with SnCl2 and K2PtCl6, respectively. The reactions are also reversible, for example, the sequences PtSn --> PtSn2 --> PtSn and PtSn --> Pt3Sn --> PtSn are all readily achievable. The strategy also allows nanocrystalline AuCu to be successfully converted into AuCu3 via reaction with Cu(C2H3O2)2.H2O, suggesting that this approach may be general.
Crystals in CrystalsNanocrystals within Mesoporous Zeolite Single Crystals
作者:Claus H. Christensen、Iver Schmidt、Anna Carlsson、Kim Johannsen、Konrad Herbst
DOI:10.1021/ja050380u
日期:2005.6.1
TEM imaging. On conventional zeolites, the supported material aggregated on the outer surface of the zeolite particles, particularly after thermal treatment. When using mesoporouszeolites, the particles were evenly distributed throughout the mesopore system of the zeolitic support, even after calcination, leading to nanocrystals within mesoporouszeolitesinglecrystals.
控制负载在沸石载体上的催化活性颗粒性能的主要因素是分散度。结果表明,在沸石单晶(silicalite-1、ZSM-5)中引入非晶介孔可提高颗粒分散程度。作为代表性实例,分别将金属 (Pt)、合金 (PtSn) 和金属碳化物 (β-Mo(2)C) 负载在常规和介孔沸石载体上,并通过 TEM 比较粒子分散程度成像。在常规沸石上,负载材料聚集在沸石颗粒的外表面上,特别是在热处理之后。当使用介孔沸石时,即使在煅烧后,颗粒均匀地分布在沸石载体的介孔系统中,
Temperature Dependence of Kinetics of Methanol Electro-oxidation on PtSn Alloys
作者:Itaru Honma、Takako Toda
DOI:10.1149/1.1623493
日期:——
The temperaturedependence of methanolelectro-oxidation properties has been investigated for Pt and PtSnalloys by highpressure rotating disk electrode (RDE) measurements. The methanol oxidation reaction (MOR), which is the anodic reaction in direct methanol fuel cells (DMFCs), has been studied in the temperature range 25-140°C. Linear sweep voltammograms of MOR can be measured up to temperatures above
Thin-Film Cu[sub 6]Sn[sub 5] Electrodes: Synthesis, Properties, and Current Collector Interactions
作者:Il-Seok Kim、J. T. Vaughey、O. Auciello
DOI:10.1149/1.2904525
日期:——
Thin-film Cu 5 Sn 5 anodes were created using a radio frequency magnetron sputtering technique. Several films were studied demonstrating different compositional variables, namely, (i) as-deposited, nanocrystalline Cu 6 Sn 5 on stainless steel, (ii) annealed Cu 6 Sn 5 on stainless steel, and (iii) Cu 6 Sn 5 /Pt film electrodes. The annealed Cu 6 Sn 5 films showed enhanced grain growth compared to the
使用射频磁控溅射技术制造薄膜Cu 5 Sn 5 阳极。研究了几种薄膜,证明了不同的成分变量,即(i)不锈钢上的沉积态纳米晶 Cu 6 Sn 5,(ii)不锈钢上的退火 Cu 6 Sn 5 和(iii)Cu 6 Sn 5 /Pt 薄膜电极。与沉积态样品相比,退火的 Cu 6 Sn 5 薄膜显示出增强的晶粒生长,发现具有更高的结晶度,并且表现出比纳米晶样品更低的锂循环容量。评估了在集电器和 Cu 5 Sn 5 膜之间包含 Pt 底层的膜,其循环容量比退火样品或典型的块状层压板高 30%。
Intermetallic Nanocatalysts from Heterobimetallic Group 10–14 Pyridine-2-thiolate Precursors
作者:Carena L. Daniels、Megan Knobeloch、Philip Yox、Marquix A. S. Adamson、Yunhua Chen、Rick W. Dorn、Hao Wu、Guoquan Zhou、Huajun Fan、Aaron J. Rossini、Javier Vela
DOI:10.1021/acs.organomet.9b00803
日期:2020.4.13
Intermetallic compounds are atomically ordered inorganic materials containing two or more transition metals and main-group elements in unique crystalstructures. Intermetallics based on group 10 and group 14 metals have shown enhanced activity, selectivity, and durability in comparison to simple metals and alloys in many catalytic reactions. While high-temperature solid-state methods to prepare intermetallic
potassium hydroxide, oleylamine, or oleic acid. Single-phase powders of a variety of intermetallic compounds were synthesized. Although not stable at the temperature of synthesis, high-temperature phases are accessible as well. The microwave-assisted polyol process opens up the possibility to synthesize intermetallic compounds in a fast and easily applicable one-step route, without the utilization of
微波辅助多元醇工艺用于合成 TM 系统中金属间相的纯相微晶或纳米晶样品(T = Co、Ni、Rh、Pd、Ir、Pt 和 M = Sn、Sb、Pb、Bi )。反应温度范围在 240 °C 和 300 °C 之间,几分钟到一小时的反应时间就足够了。为优化合成反应温度、反应时间和金属前驱体。为了获得相纯样品,该过程通过添加氢氧化钾、油胺或油酸进一步改进。合成了多种金属间化合物的单相粉末。虽然在合成温度下不稳定,但也可以进入高温相。