MXene is one of the most interesting two-dimensional (2D) materials that have been discovered. With more than 70% of publication-related studies, titanium-based MXene (Ti-MXene) has been well-evaluated, hence, laying the very first foundation of the 2D MXene with tailorable properties acquainted with a diverse range of applications. Yet there are still other candidates amongst transitional metals that can play the role of 2D MXene well beyond known applications. In this critical review, we provide a systematic discussion of the preparations, properties, challenges, key findings, and applications of less-evaluated M-MXene where M represents other non-Ti transitional metals. In certain applications, such as electrocatalysis and energy storage, the remarkable properties of non-Ti MXene exceed the performance of conventional Ti-MXene. Indeed, there has been a lot of progress in the top-down and bottom-up synthesis of MXenes that can precisely control the properties of M-MXene catering advanced applications. From the main challenges in preparing complicated M-MXenes to the choice of their applications accordingly to their well-established properties, this review provides a comprehensive evaluation of published studies. This review also studies the progress in double metal combinations, and other metal candidates expanded outside the IIIB to VIB family group and the further expansion of the 2D metal carbide/nitride/carbonitride to the 2D metal boride family. Lastly, this critical review ends with the prospects and further suggestions for the direction of MXene in nanomaterial development.

MXene 是已发现的最有趣的二维 (2D) 材料之一。在超过 70% 的出版物相关研究中，钛基 MXene (Ti-MXene) 得到了很好的评估，因此为 2D MXene 奠定了第一个基础，该 2D MXene 具有适合各种应用的可定制特性。然而，过渡金属中还有其他候选材料可以发挥 2D MXene 的作用，远远超出已知的应用范围。在这篇重要的评论中，我们系统地讨论了 M-MXene 的制备、性质、挑战、主要发现和应用，其中 M 代表其他非 Ti 过渡金属。在某些应用中，例如电催化和储能，非 Ti MXene 的卓越性能超过了传统 Ti-MXene 的性能。的确，自上而下和自下而上的 MXenes 合成已经取得了很大进展，可以精确控制 M-MXene 的性质以满足高级应用。从制备复杂 M-MXenes 的主要挑战到根据其公认的特性选择应用，这篇综述对已发表的研究进行了全面评估。本综述还研究了双金属组合的进展，以及从 IIIB 族扩展到 VIB 族群的其他候选金属，以及二维金属碳化物/氮化物/碳氮化物进一步扩展到二维金属硼化物族。最后，这篇批判性评论以 MXene 在纳米材料发展方向的前景和进一步建议作为结尾。