Ni@onion-like carbon and Co@amorphous carbon: control of carbon structures by metal ion species in MOFs

We first report the facile synthesis of metal-carbon composites consisting of metal nanoparticles (NPs) and different types of carbon species: onion-like and amorphous carbon, Ni@onion-like carbon and Co@amorphous carbon. By simply changing the metal species in an isostructural metal-organic framework, thermal decompositions of MOF-74 directly afforded different types of metal NPs and carbon composites, which exhibited good electrical conductivity. In particular, the Ni@onion-like carbon, having a well-ordered carbon structure, had high electrical conductivity (sigma = 5.3 omega(-1) cm(-1) at 295 K), explained by a modified model of the Efros-Shklovskii variable range hopping

金属混合と熱処理による多孔性配位高分子複合材料の合成と物性に関する研究

京都大学新制・論文博士博士(理学)乙第13478号論理博第1578号新制||理||1692(附属図書館)(主査)教授 北川 宏, 教授 吉村 一良, 教授 竹腰 清乃理学位規則第4条第2項該当Doctor of ScienceKyoto UniversityDGA

Nanoparticle/metal–organic framework hybrid catalysts: elucidating the role of the MOF

Hybrid materials of metal–organic frameworks (MOFs) and nanoparticles (NPs) have attracted significant attention because of the wide variety of attractive properties derived from the two components. In the last decade, the development of synthesis techniques for NP/MOF composites was particularly significant. In the field of catalysis in particular, various synergistic effects that make the composites attractive catalysts have been reported. However, the role of MOFs in the composite catalysts is still not well understood and is being elucidated. In this feature article, we focus on recent progress in NP/MOF composite catalysts, concentrating on the analysis of the interaction between NPs and MOFs and the reaction mechanisms, together with the synthetic techniques used for NP/MOF hybrid materials

Chemical Synthesis, Characterization and Properties of Multi‐Element Nanoparticles

Multi-element nanoparticles (NPs) consisting of five or more elements have been increasingly studied in the past 5 years. Their emergence is taking materials science one step further because they exhibit superior properties to conventional NPs in a range of respects, including catalysis. This review focuses on the recent progress in multi-element NPs regarding synthesis, especially in regard to chemical synthesis, characterization, and properties. We begin with a brief introduction of the multi-element NPs and an overview of their synthesis methods. Then, we present representative examples of multi-element alloy NPs and ceramic NPs, including oxide NPs prepared by chemical syntheses. This review intends to provide useful insights into the chemical methods that are used to synthesize multi-element NPs, and includes a discussion on the possibilities arising from their use in new functional materials

Systematic Tuning of the Magnetic Properties in Mixed-Metal MOF-74

Recently, mixed-metal metal–organic frameworks (MOFs) have been attracting much attention in various fields. In this study, we have systematically investigated the magnetic properties of CoxNi₁–x-MOF-74 [Co₂xNi₂(₁–x)(dhtp), where H₄dhtp = 2, 5-dihydroxyterephthalic acid] with two different kinds of metals (Co and Ni) across the composition range 0 ≤ x ≤ 1. Bimetallic CoxNi₁–x-MOF-74 (x = 0.752, 0.458, and 0.233) were successfully synthesized and confirmed to have homogeneous metal distributions. Weak ferromagnetic (canted antiferromagnetic) behavior was exhibited, while homometallic Co-MOF-74 and Ni-MOF-74 are antiferromagnetic. We also investigated the effects of C₂H₄ sorption on the magnetic properties and found that C₂H₄-adsorbed Co₀.₅Ni₀.₅-MOF-74 exhibited a change in the interchain magnetic interaction