应变对析氢反应催化剂TiC_(2)性能影响的研究

Investigation of strain effect on hydrogen evolution reaction catalysts of TiC_(2)

应变工程是一种有效地用来调整原子薄膜材料的电子、磁性和光学性能的策略.利用第一性原理计算,我们表明应变也可以有效地调节Ti C_(2)的析氢反应(HER)的催化活性,这是电解水电化学制氢所必需的.我们主要考虑0-8%范围的拉伸应变,研究发现,在25%的氢覆盖率下双轴拉伸比单轴拉伸能更有效的提高HER活性,但b方向拉伸后的Ti C_(2)结构具有更高的氢最大覆盖率,且b方向的拉伸应变对不同氢覆盖率的Ti C_(2)单层片的催化性能都有很大的提高.电子结构计算表明,拉伸应变可以激活相对惰性的内部价电子,从而引起体系的失稳和催化活性的提高.在本工作中获得的见解可能有助于利用应变作为一种有效手段来提高二维材料的催化活性,并探索更有效地调整其电子结构和催化活性的新方法.

Strain engineering is an effective strategy to tune the electronic, magnetic and optical properties of atomically thin materials. Using first-principles calculations, we show that strain is also effective for tuning the catalytic activity of TiC_(2) towards the hydrogen evolution reaction (HER ), which is essential for electrochemical hydrogen from water splitting. We only consider the range from 0 to 8%. It is found that biaxial tensile strain can enhance the HER activity more effectively than uniaxial stretching at 25% hydrogen coverage. However, the TiC_(2) sheet has the highest maximum hydrogen coverage by the stretching in the b direction, and the tensile strain in the b direction greatly improves the catalytic performance of TiC_(2) monolayers with different hydrogen coverages. Electronic structure calculations show that tensile strain can activate the relatively inert inner valence electrons, which leads to the instability of the system and the improvement of catalytic activity. The insights obtained in the present work may prove to be instrumental in improving the catalytic activity of two-dimensional materials using strain as an effective means and in exploring new approaches for more effectively tuning their electronic structure and catalytic activities.