Kaneko Hisashi, Matsumoto Takatoshi, Cuya Huaman Jhon L, Ishijima Masanao, Suzuki Kazumasa, Miyamura Hiroshi, Balachandran Jeyadevan
Department of Materials Science, The University of Shiga Prefecture, Hikone, Shiga 522-8533, Japan.
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan.
Inorg Chem. 2021 Mar 1;60(5):3025-3036. doi: 10.1021/acs.inorgchem.0c03266. Epub 2021 Feb 16.
Development of a technology for the synthesis of monometallic or multimetallic nanoparticles is exceptionally vital for the preparation of novel magnetic, optical. and catalytic functional materials. In this context, the polyol process is a safe and scalable method for preparation of metal nanoparticles with controlled sizes and shapes in large scales. However, there is no systematic investigation that discusses the criteria for the selection of metal salt and solvent type that determine the kinetics of reduction reaction that influences the morphology of the particles. Consequently, the design of metallic nanoparticles, which is controlled by the kinetics and thermodynamics of the reduction reaction, has become difficult. In this paper, the selection criterion for metal salt precursor is established based on the presumption that the ligand of the metal precursor promotes the formation of active species of the solvent, and the criterion for the selection of the solvent type is based on the highest occupied molecular orbital (HOMO) energy value estimated using molecular orbital theory. The results suggested that the dissociation constants of metal salt precursors and HOMO energy of the polyol solvent can be tuned to control the kinetics of the reduction reaction. The reduction potential of polyol depends on the number of carbon atoms and the location of hydroxyl ligands within the molecule. Among the polyols considered in this study, 1,4-butanediol had the highest reduction potential. The predictions have been experimentally verified by synthesizing metallic Co and Fe nanoparticles. The findings could be extended to other techniques such as thermal decomposition and alcohol reduction for the synthesis of noble metal-transition metal magnetic and catalytic nanoparticles with novel properties.
开发一种用于合成单金属或多金属纳米颗粒的技术对于制备新型磁性、光学和催化功能材料极为重要。在这种情况下，多元醇法是一种安全且可扩展的方法，可大规模制备尺寸和形状可控的金属纳米颗粒。然而，目前尚无系统研究讨论决定影响颗粒形态的还原反应动力学的金属盐和溶剂类型的选择标准。因此，由还原反应的动力学和热力学控制的金属纳米颗粒的设计变得困难。本文基于金属前驱体的配体促进溶剂活性物种形成的假设，建立了金属盐前驱体的选择标准，溶剂类型的选择标准基于用分子轨道理论估算的最高占据分子轨道（HOMO）能量值。结果表明，可以调节金属盐前驱体的解离常数和多元醇溶剂的HOMO能量来控制还原反应的动力学。多元醇的还原电位取决于分子内碳原子的数量和羟基配体的位置。在本研究中考虑的多元醇中，1,4 - 丁二醇具有最高的还原电位。通过合成金属钴和铁纳米颗粒，对这些预测进行了实验验证。这些发现可扩展到其他技术，如热分解和醇还原，用于合成具有新颖性质的贵金属 - 过渡金属磁性和催化纳米颗粒。
