标题： 共价MAX相的子层编辑用于纳米层状早期过渡金属化合物 显示英文标题

标题： Sublayers Editing of Covalent MAX Phase for Nanolaminated Early Transition Metal Compounds

摘要： 二维过渡金属碳化物和氮化物(MXenes)由于其多样的元素组成和可变的表面终止( T )，在能量存储、催化和电磁干扰等领域受到关注。 通常，MXene材料的合成涉及使用HF酸或路易斯酸熔盐蚀刻三元层状过渡金属碳化物和氮化物(MAX相)中的弱M-A金属键，而强M-X共价键则保留MXene的二维框架结构。 另一方面，MAX相材料家族还包括一类重要的成员，其中A位被非金属主族元素(如硫和磷)占据，在这些材料中，M-A和M-X都是共价键类型的亚层。 上述蚀刻方法不能用于从这些母相中合成MXene材料。 在本工作中，我们发现共价键类型的M-A和M-X亚层在高温熔融状态下与某些无机材料表现出不同的反应性。 通过利用这种反应性的差异，我们可以对这些共价亚层进行结构修饰，从而实现X位点元素的替换(从B到Se、S、P、C)，并将非范德华力(non-vdW) MAX相中的非金属A位原子转化为范德华力(vdW)层状材料的表面原子。 这导致了一类早期过渡金属氧化物硫属化物(TMXCs)，它们表现出MXene和过渡金属硫属化物的晶格特性。 使用电子供体化学剪刀，这些TMXC层状材料可以进一步剥离成单层纳米片。 这些单层TMXCs中每个原子的原子构型与传统MXenes相同，但M位原子的氧化态可以通过X位原子和插入的阳离子进行调节。 显示英文摘要

摘要： Two-dimensional transition metal carbides and nitrides (MXenes) have gained popularity in fields such as energy storage, catalysis, and electromagnetic interference due to their diverse elemental compositions and variable surface terminations (T). Generally, the synthesis of MXene materials involves etching the weak M-A metallic bonds in the ternary layered transition metal carbides and nitrides (MAX phase) using HF acid or Lewis acid molten salts, while the strong M-X covalent bonds preserve the two-dimensional framework structure of MXenes. On the other hand, the MAX phase material family also includes a significant class of members where the A site is occupied by non-metal main group elements (such as sulfur and phosphorus), in which both M-A and M-X are covalent bond-type sublayers. The aforementioned etching methods cannot be used to synthesize MXene materials from these parent phases. In this work, we discovered that the covalent bond-type M-A and M-X sublayers exhibit different reactivity with some inorganic materials in a high-temperature molten state. By utilizing this difference in reactivity, we can structurally modify these covalent sublayers, allowing for the substitution of elements at the X site (from B to Se, S, P, C) and converting non-metal A site atoms in non-van der Waals (non-vdW) MAX phases into surface atoms in vdW layered materials. This results in a family of early transition metal Xide chalcogenides (TMXCs) that exhibit lattice characteristics of both MXenes and transition metal chalcogenides. Using electron-donor chemical scissors, these TMXC layered materials can be further exfoliated into monolayer nanosheets. The atomic configurations of each atom in these monolayer TMXCs are the same as those of conventional MXenes, but the oxidation states of the M-site atoms can be regulated by both X-site atoms and intercalated cations.