方解石晶体结构及表面活性位点第一性原理

The first principles of the crystal structure and active sites of calcite

基于密度泛函理论的第一性原理,采用Materials Studio 6.1软件的CASTEP模块对方解石的晶体结构及与水分子及水分子簇的吸附作用进行了研究.结果表明,方解石在参与化学反应时O的活性最强,C和Ca次之;其次确定了最稳定解离面为{1014}切面,其Ca和O位点与单个水分子形成吸附,且与O位点吸附作用较强,H(H_2O)—O(CaCO_3)键与H(H_2O)—O(H_2O)键间形成氢键;{1014}切面水分子簇相互作用,水分子间及水分子与方解石表面均存在氢键作用,吸附发生在O位点和Ca位点,且主要发生在O位点.

The calcite structure and the adsorption of water molecules as well as water molecule clusters on it were investigated using the CASTEP module,Materials Studio 6.1 based on the first principles of the density functional theory（DFT）.Results indicate that the O site of calcite shows the highest activity in the reaction process,followed by the C and Ca sites;{101-4} is the most stable cleavage plane,where the adsorption can occur between the water molecule and the Ca and O sites,and the O site shows a more stronger adsorption effect with the hydrogen bond formed through the H（H2O）-O（CaCO3）and H（H2O）-O（H2O）bonds.There are both hydrogen bonds between the water molecules,as well as the water molecules and calcite surface whose adsorption effects are mainly found to be the O site followed by the relative weaker Ca site.