As a newcomer to the family of two-dimensional (2D) material, 2D metals and alloys have seen rapid development in recent years because of their unique physical and chemical properties. Unlike freestanding atomistically thin 2D materials, such as graphene, the synthesis of 2D metals and alloys has been focused on either atomistically thin films under nanoscale geometric confinements or freestanding ultrathin films with a thickness ranging from a few to tens of nanometers. In this article, we will first review the recent theoretical works that aimed to understand the thermodynamic stability of 2D metals with or without geometrical confinements. After that, we will focus on the variety of methods that were developed to synthesize 2D metals and/or alloys. Finally, we will briefly discuss some state-of-the-art applications of 2D metals in bioimaging, photothermal therapy, sensing, nanodevices, and catalysis.

作为二维（2D）材料家族的新成员，二维金属和合金由于其独特的物理和化学特性，近年来发展迅速。与独立式原子薄的2D材料（例如石墨烯）不同，二维金属和合金的合成已集中在纳米级几何约束下的原子性薄膜或厚度从几纳米到几十纳米的独立式超薄薄膜上。在本文中，我们将首先回顾最近的理论工作，这些工作旨在了解具有或不具有几何限制的二维金属的热力学稳定性。在那之后，我们将专注于开发用于合成2D金属和/或合金的各种方法。最后，我们将简要讨论2D金属在生物成像中的一些最新应用，