The activation of B-H bonds in borohydride on Cu(100) and Cu (110) surfaces

Abstract

In this study, the dehydrogenation of borohydride (BH4) on Cu(1 0 0) and Cu(1 1 0) surfaces has been studied using Density-Functional Theory (DFT) method. First, the adsorption geometries and energies of BHx species and H on Cu(1 0 0) and Cu(1 1 0) surfaces have been determined. Then, the activation barrier in each dehydrogenation step was determined to have transition state (TS) structures using the Linear and Quadratic Synchronous Transit (LST/QST) method. Repetitive hydrogen abstraction from BHx species (x = 0 -> 4) has been considered in this stage. It is concluded that the rate-determining step for BH4 dehydrogenation is regarded as the fourth step of dehydrogenation on both surfaces. Moreover, the activation barrier of the first dehydrogenation step on the Cu (10 0) surface is smaller than Cu(1 1 0) surface. In other dehydrogenation steps, the activation barriers on the Cu (100) and Cu(1 1 0) surfaces is lower than Cu(1 1 1) surface.