Phase has emerged as an important structural parameter — in addition to composition, morphology, architecture, facet, size and dimensionality — that determines the properties and functionalities of nanomaterials. In particular, unconventional phases in nanomaterials that are unattainable in the bulk state can potentially endow nanomaterials with intriguing properties and innovative applications. Great progress has been made in the phase engineering of nanomaterials (PEN), including synthesis of nanomaterials with unconventional phases and phase transformation of nanomaterials. This Review provides an overview on the recent progress in PEN. We discuss various strategies used to synthesize nanomaterials with unconventional phases and induce phase transformation of nanomaterials, by taking noble metals and layered transition metal dichalcogenides as typical examples. Moreover, we also highlight recent advances in the preparation of amorphous nanomaterials, amorphous–crystalline and crystal phase-based hetero-nanostructures. We also provide personal perspectives on challenges and opportunities in this emerging field, including exploration of phase-dependent properties and applications, rational design of phase-based heterostructures and extension of the concept of phase engineering to a wider range of materials.

除了成分、形态、结构、刻面、大小和维度之外，相位已成为决定纳米材料的特性和功能的重要结构参数。特别是，在块状状态下无法获得的纳米材料中的非常规相可能赋予纳米材料有趣的特性和创新应用。纳米材料的相工程（PEN）取得了很大进展，包括具有非常规相的纳米材料的合成和纳米材料的相变。本综述概述了 PEN 的最新进展。我们讨论了用于合成具有非常规相的纳米材料并诱导纳米材料相变的各种策略，以贵金属和层状过渡金属二硫化物为例。此外，我们还重点介绍了制备非晶纳米材料、非晶-结晶和基于晶相的异质纳米结构的最新进展。我们还就这一新兴领域的挑战和机遇提供了个人观点，包括相位相关特性和应用的探索、基于相位的异质结构的合理设计以及将相位工程概念扩展到更广泛的材料。