Remodeling and adsorption behavior of Co2+-doped SnO2 (221) crystal plane by H2O molecules

In this paper, Co2+-doped SnO2 (221) crystal plane materials were synthesized, and the remodeling effect of the H2O molecular crystal plane and molecular adsorption behavior was studied by Density Functional Theory (DFT) simulation. The DFT simulation results show that the remodeling mechanism of H2O molecules on the crystal plane is as follows: the doping of Co2+ makes the crystal planes form oxygen defects on the crystal planes, which are further remodeled by H2O molecules during the synthesis process to be hydroxylated. The hydroxylated crystal surface adsorbs the O2 molecule (hydrogen bond), and then adsorbs the H2O molecule on the adsorbed O2 molecule (hydrogen bond). The theoretical simulation results show that the remodeling of the H2O molecule affects the electrical conductivity of the crystal plane. After the hydroxylated crystal plane further adsorbs O2, N2 and H2O molecules, the electrical conductivity of the crystal plane increases, weakly increases and decreases, respectively.