BH4 dissociation on various metal (1 1 1) surfaces: A DFT study.

Graphical abstract Highlights • Sequential BH 4 dehydrogenation have been investigated by DFT for the first time. • Adsorption and decomposition mechanism have been clarified on all surfaces. • Lateral interactions between adsorbates are effective on Reaction Energy Diagram. • Au(1 1 1) is the most active surface, however Cu(1 1 1) can compete with it. Abstract In this study, the catalytic effect of various metal surfaces on the sequential decomposition of BH 4 molecule has been studied by Density Functional Theory (DFT) for the first time. For this purpose, the sequential dissociation of BH x (x = 0 → 4) molecules on Au, Cu, Al and Ag (1 1 1) surfaces were systematically investigated. At first, ground state structures of BH x (x = 0 → 4) molecules and their decomposed versions such as BH x + yH (x + y = 4) were obtained. Then, transition state search calculations were performed to find activation barriers related to every BH x + yH (x + y = 4) decomposition step until x = 0 has been reached. An additional hydrogen atom(s) remaining from a previous step accepted as if they(it) are(is) at infinite distances from the central unit cell of the surface because it is prerequisite to form energy diagram which keeps the number of the atom(s) constant. Our calculations were supported with the lateral interaction energies and the various bond distances to clarify catalytic abilities of the surfaces. It is concluded that Au(1 1 1) surface is the most active surface among the others however the activity of the Cu(1 1 1) surface can compete with it. Al(1 1 1) and Ag(1 1 1) surfaces are the least active surfaces. This knowledge can be used to develop strategies to design Cu-based cheap and active catalyst for hydrogen generation from borohydride dissociation. [ABSTRACT FROM AUTHOR]