Following these hypotheses, the number of H atoms that can be adsorbed on the Pd cuboctahedron surface (for a given m, denoted NH,Pd) can be calculated as follows (Equation (3)): (3)NH,Pd=N3hcp(5,5,5)+N3hcp(5,7,7)+N3hcp(7,7,9)+N3fcc(9,9,9)+N4(5,5,5,5)+N4(5,7,7,8)+N4(7,7,8,8)+N4(8,8,8,8)