二维Ti2C与Ti3C2表面OH、O、F、Au的吸附活性

较高的比表面积与稳定性使得二维Ti₂C与Ti₃C₂结构在贵金属催化剂载体、锂离子电池、储氢材料等领域具有重要的应用前景. 研究Ti₂C、Ti₃C₂的表面吸附活性有助于认识其表面特征. 第一性原理计算研究显示:Ti₂C与Ti₃C₂对O、OH、F具有较强的吸附活性. 通过比较Ti₂C、Ti₃C₂、Ti(001)、TiC(001)的表面电子结构, 我们发现Ti₂C与Ti₃C₂较强的表面吸附活性来自于表面Ti 原子未极化的3d轨道. 这使得Ti₂C、Ti₃C₂表面通常覆盖有O、F、OH. 吸附了O、OH基团的Ti₂C与Ti₃C₂结构(Ti₂CO_2-2x(OH)_2x、Ti₃C₂O_2-2x(OH)_2x)对Au原子的吸附能随OH比例的增大而增大.

Adsorption Activities of O,OH, F and Au on Two-Dimensional Ti2C and Ti3C2 Surfaces

Two-dimensional Ti₂C and Ti₃C₂ structures are highly stable and have high specific surface areas, and therefore represent promising materials with potential applications as carriers in transition metal catalysis, Li-ion batteries, and hydrogen storage devices. It was envisaged that investigating the surface adsorption activities of Ti₂C and Ti₃C₂ would provide useful information about their surface properties. The results of a firstprinciples study showed that the adsorption energies of OH, O, and F on Ti₂C and Ti₃C₂ surfaces were quite high. By comparing the electronic properties of Ti₂C, Ti₃C₂, Ti(001), and TiC(001), we found that the un-polarized Ti- 3d orbitals were responsible for the high surface adsorption activities of these materials. The high surface adsorption activities of the Ti₂C and Ti₃C₂ materials caused them to be terminated with O, F, and OH surface groups. The surface adsorption energies of the Au particles on the Ti₂CO_2-2x(OH)_2x and Ti₃C₂O_2-2x(OH)_2x) surfaces increase as the ratio of OH increased.