Key Laboratory for Photonic and Electronic Bandgap Materials, Ministry of Education, Harbin Normal University, Harbin, 150025, China.
J Mol Model. 2013 Dec;19(12):5143-52. doi: 10.1007/s00894-013-2013-7. Epub 2013 Oct 5.
Motivated by the great advance in graphene hydroxide--a versatile material with various applications--we performed density functional theory (DFT) calculations to study the functionalization of the two-dimensional hexagonal boron nitride (h-BN) sheet with hydroxyl (OH) radicals, which has been achieved experimentally recently. Particular attention was paid to searching for the most favorable site(s) for the adsorbed OH radicals on a h-BN sheet and addressing the roles of OH radical coverage on the stability and properties of functionalized h-BN sheet. The results indicate that, for an individual OH radica, the most stable configuration is that it is adsorbed on the B site of the h-BN surface with an adsorption energy of -0.88 eV and a magnetic moment of 1.00 μ(B). Upon adsorption of more than one OH radical on a h-BN sheet, however, these adsorbates prefer to adsorb in pairs on the B and its nearest N atoms from both sides of h-BN sheet without magnetic moment. An energy diagram of the average adsorption energy of OH radicals on h-BN sheet as a function of its coverage indicates that when the OH radical coverage reaches to 60 %, the functionalized h-BN sheet is the most stable among all studied configurations. More importantly, this configuration exhibits good thermal and dynamical stability at room temperature. Owing to the introduction of certain impurity levels, the band gap of h-BN sheet gradually decreases with increasing OH coverage, thereby enhancing its electrical conductivity.
受氧化石墨稀这一具有广泛应用的多功能材料的巨大进步的启发，我们运用密度泛函理论（DFT）计算研究了最近在实验上实现的羟基（OH）自由基对二维六方氮化硼（h-BN）片的功能化。特别关注的是寻找吸附在 h-BN 片上的 OH 自由基的最有利位置，并解决 OH 自由基覆盖率对功能化 h-BN 片的稳定性和性质的影响。结果表明，对于单个 OH 自由基，最稳定的构型是其吸附在 h-BN 表面的 B 位上，吸附能为-0.88 eV，磁矩为 1.00 μ（B）。然而，当多于一个 OH 自由基吸附在 h-BN 片上时，这些吸附物更喜欢从 h-BN 片的两侧成对地吸附在 B 和其最近邻的 N 原子上，没有磁矩。OH 自由基在 h-BN 片上的平均吸附能随其覆盖率的能量图表明，当 OH 自由基覆盖率达到 60%时，功能化 h-BN 片在所有研究构型中是最稳定的。更重要的是，这种构型在室温下表现出良好的热和动力学稳定性。由于引入了一定的杂质能级，h-BN 片的带隙随着 OH 覆盖率的增加而逐渐减小，从而提高了其电导率。
