Unconventional 1T′-phase transition metal dichalcogenides (TMDs) have aroused tremendous research interest due to their unique phase-dependent physicochemical properties and applications. However, due to the metastable nature of 1T′-TMDs, the controlled synthesis of 1T′-TMD monolayers (MLs) with high phase purity and stability still remains a challenge. Here we report that 4H-Au nanowires (NWs), when used as templates, can induce the quasi-epitaxial growth of high-phase-purity and stable 1T′-TMD MLs, including WS₂, WSe₂, MoS₂ and MoSe₂, via a facile and rapid wet-chemical method. The as-synthesized 4H-Au@1T′-TMD core–shell NWs can be used for ultrasensitive surface-enhanced Raman scattering (SERS) detection. For instance, the 4H-Au@1T′-WS₂ NWs have achieved attomole-level SERS detections of Rhodamine 6G and a variety of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike proteins. This work provides insights into the preparation of high-phase-purity and stable 1T′-TMD MLs on metal substrates or templates, showing great potential in various promising applications.

非常规1T'相过渡金属二硫属化物（TMD）由于其独特的相依赖性物理化学性质和应用而引起了巨大的研究兴趣。然而，由于1T'-TMD的亚稳态性质，具有高相纯度和稳定性的1T'-TMD单层（ML）的受控合成仍然是一个挑战。在这里，我们报道了4H-Au纳米线（NW）作为模板时，可以诱导高相纯度和稳定的1T'-TMD ML的准外延生长，包括WS ₂，WSe ₂，MoS ₂和MoSe ₂，通过简单快速的湿化学方法。合成的4H-Au@1T′-TMD核壳纳米线可用于超灵敏表面增强拉曼散射（SERS）检测。例如，4H-Au@1T′-WS ₂ NW已经实现了罗丹明6G和多种严重急性呼吸综合征冠状病毒2（SARS-CoV-2）刺突蛋白的阿托摩尔级SERS检测。这项工作为在金属基底或模板上制备高相纯度和稳定的 1T'-TMD ML 提供了见解，在各种有前途的应用中显示出巨大的潜力。