Ultrathin transition-metal oxides (TMOs) from nonlayered bulk structures are emerging 2D materials. Here we investigate the reactivity of a 2D TMO of varying thickness from first principles. We find that the band gap of the 2D nL-TiO₂(110) shows a strong linear correlation with its surface reactivity: the smaller the band gap, the more reactive the surface oxygen; 3L-TiO₂(110) has the smallest band gap and the highest reactivity. We further design Pt₁ single-atom catalysts (SAC) by substituting a Pt single atom for a surface Ti atom. We find that the band gap of nL-TiO₂(110) dictates both chemisorption and dissociation of CH₄ on Pt₁-nL-TiO₂(110): the smaller the band gap, the stronger the adsorption of CH₄ and the lower the barrier of heterolytic C–H activation of CH₄. We propose that band gap can be a novel and direct descriptor for the reactivity of 2D TMOs and their supported SACs.

中文翻译：

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带隙作为二维二氧化钛及其支持的Pt单原子对甲烷活化反应性的新型描述子

来自非分层体结构的超薄过渡金属氧化物（TMO）是新兴的2D材料。在这里，我们从第一原理出发，研究了厚度变化的2D TMO的反应性。我们发现2D n L-TiO ₂（110）的带隙与它的表面反应性显示出很强的线性关系：带隙越小，表面氧的反应性越强；3L-TiO ₂（110）具有最小的带隙和最高的反应性。我们通过用Pt单原子替代表面Ti原子来进一步设计Pt ₁单原子催化剂（SAC）。我们发现n L-TiO ₂（110）的带隙决定了Pt ₁上CH _4的化学吸附和解离- Ñ L-的TiO ₂（110）：带隙越小，越强CH的吸附₄和下部异裂CH活化CH的屏障₄。我们建议带隙可以是2D TMO及其支持的SAC的反应性的新颖和直接的描述符。