Fig. 5. The overpotential-determining step as a function of H configuration on the NW. (a) A single H atom on the edge and the 1st NN to the adsorbed CO; (b) a single H atom on the facet and the 1st NN to CO; (c) a single H atom on the facet and the 2nd NN to CO; (d) a single H atom on the edge and the 2nd NN to CO; (e) one H on the facet and another H on the edge; both are 1st NNs to CO; (f) two H atoms on the facet and the 1st NNs to CO.