The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, 30332, USA.
Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes, 748, 05508-000, São Paulo-SP, Brazil.
Chemistry. 2018 Nov 16;24(64):16944-16963. doi: 10.1002/chem.201802194. Epub 2018 Aug 24.
There is a growing interest in controlling the synthesis of colloidal metal nanocrystals and thus tailoring their properties toward various applications. In this context, choosing an appropriate combination of reagents (e.g., salt precursor, reductant, capping agent, and stabilizer) plays a pivotal role in enabling the synthesis of metal nanocrystals with diversified sizes, shapes, and structures. Here we present a comprehensive review that highlights one of the key reagents for the synthesis of metal nanocrystals via chemical reduction: the reductants. We start with a brief introduction to the compounds commonly employed as reductants in the colloidal synthesis of metal nanocrystals by showing their oxidation half-reactions and the corresponding oxidation potentials. Then we offer specific examples pertaining to the controlled synthesis of metal nanocrystals, followed by some fundamental aspects covering the general mechanisms of metal ion reduction based on the Marcus Theory. Afterwards, we present a case-by-case discussion on a wide variety of reductants, including their major properties, reduction mechanisms, and additional effects on the final products. We illustrate these aspects by selecting key examples from the literature and paying close attention to the underlying mechanism in each case. At the end, we conclude by summarizing the highlights of the review and providing some perspectives on future directions.
人们对控制胶体金属纳米晶体的合成越来越感兴趣，从而可以根据各种应用来调整其性质。在这种情况下，选择合适的试剂组合（例如盐前体、还原剂、封端剂和稳定剂）对于实现具有不同尺寸、形状和结构的金属纳米晶体的合成起着至关重要的作用。在这里，我们提供了一个全面的综述，重点介绍了通过化学还原法合成金属纳米晶体的关键试剂之一：还原剂。我们首先简要介绍了在胶体合成金属纳米晶体中常用的作为还原剂的化合物，展示了它们的氧化半反应和相应的氧化电势。然后，我们提供了有关金属纳米晶体的控制合成的具体实例，随后涵盖了基于马库斯理论的金属离子还原的一般机制的一些基本方面。之后，我们对各种还原剂进行了逐一讨论，包括它们的主要性质、还原机制以及对最终产物的其他影响。我们通过从文献中选择关键示例并密切关注每种情况下的潜在机制来说明这些方面。最后，我们总结了综述的要点，并对未来的发展方向提出了一些看法。
