Adsorption and dissociation of 2-mercaptobenzothiazole on Cu (1 1 1): A DFT study

Adsorption of 2-mercaptobenzothiazole (MBT) on copper was in detail investigated using density functional theory (DFT) calculations in this paper. Simulations of six adsorption modes (thiol-S, thione-S, thiol-S + N, thiol-S + S, thione-S + N and thione-S + S) were performed. It was found that neutral MBT molecule prefers to adsorb on the 5 × 5 surface of Cu (1 1 1) in the two-atom modes, and the thione-form MBT can more stably adsorb on the surface than the thiol-form MBT. The dissociation of MBT-thiol adsorbed in the thiol-S mode needs to overcome higher energy barrier than in both thiol-S + S and thiol-S + N modes. For the thione-S + N mode, in addition to the relatively high energy barrier, the dissociation reaction exhibits a weak exothermic effect. In the flat manner, the dissociation of MBT-thiol on the surface is energetically more favorable than that of MBT-thione. In addition, the adsorption of MBT anion on Cu (1 1 1) was investigated through the introduction of a thermodynamic circle. It was demonstrated that the MBT anion can adsorb on copper surface more strongly than the neutral MBT molecules.