论文标题
羟格兰烯：氢键网络的动力学
Hydroxygraphene: dynamics of hydrogen bond networks
论文作者
论文摘要
使用分子动力学方法，模拟了石墨烯片表面上出现氢键（Hb）网络的动力学，在其羟基OH功能化过程中。证明两个OH组在共价附加在薄板的一侧上，形成一个更有利的结构，以形成纸的价值键的六角形的碳原子。将OH基团连接到位于价债券六角形的另一个顶点的碳原子，这会导致羟格雷芬C $ _4 $（OH）的出现。在平坦基材上的这样的纸中，其外表面上的氧原子形成了六角形晶格，并且由于其转弯而导致的羟基可以以各种方式形成氢键的链条。从两侧进行修改会导致形成石墨烯薄板两侧HB网络的羟格雷芬C $ _2 $（OH）。对这些板的动力学的模拟表明，当温度升高时，它们在低温下的热容量会单调增加，在$ t = t_0 $时达到其最大值，然后单调降低。初始生长是由氢键晶格中定向缺陷的积累引起的，而在$ t> t_0 $下的减少是由晶格的“熔化”解释的。对于连接到纳米替宾外侧的OH组链，熔化温度为$ t_0 = 500 $ k，而对于一侧修改的石墨烯表C4（OH），$ t_0 = 260 $ k，对于石墨烯表C $ _2 $ _2 $（OH），在双方修改了$ T_0 = 485 = 485 $ K。
Using the molecular dynamics method, dynamics of hydrogen bond (HB) networks emerging on the surface of a graphene sheet during its functionalization with hydroxyl groups OH are simulated. It is demonstrated that two OH groups form an energetically more advantageous structure when they are covalently attached on one side of the sheet to carbon atoms forming opposite vertices of one hexagon of valence bonds of the sheet. Attaching of OH groups to carbon atoms located at the opposite vertices of hexagons of valence bonds leads to the emergence of hydroxygraphene C$_4$(OH). In such sheet lying on a flat substrate, attached oxygen atoms on its outer surface form a hexagonal lattice, and hydroxyl groups due to their turns can in various ways form chains of hydrogen bonds. The modification of the sheet from two sides results in forming of hydroxygraphene C$_2$(OH) with HB networks on both sides of the graphene sheet. Simulation of the dynamics of these sheets shows that their heat capacity at low temperatures $T<T_0$ increases monotonously when the temperature rises, reaches its maximum at $T=T_0$ and then decreases monotonically. The initial growth is caused by the accumulation of orientational defects in the lattice of hydrogen bonds whereas the decrease at $T>T_0$ is explained by the "melting" of the lattice. For one chain of OH groups connected to the outer side of a nanoribbon the melting temperature is $T_0=500$K, while for a graphene sheet C4(OH) modified on one side $T_0=260$K, and for a graphene sheet C$_2$(OH) modified on both sides $T_0=485$K.
