Hydrogen adsorption and desorption on the Pt and Pd subnano clusters - a review

In this review, we present our recent first principles studies on the sequential H(2) dissociative chemisorption and H desorption on the Pt(n) and Pd(n) clusters (n=2-9, 13). Upon full saturation by H atoms, the calculated H(2) dissociative chemisorption energy and H desorption energy on Pt(13) and Pd(13) clusters are similar to the corresponding values on smaller close-packed clusters. Indeed, the catalytic performances of these subnano clusters do not vary significantly with the particle sizes or shapes. Instead, they are dependent on the surface metal atoms which can be accessed by H atoms. In addition to the coverage dependency of the H(2)dissociative chemisorption and H sequential desorption energies, the phase transition of both Pt(13) and Pd(13) from the icosahedral to fcc-like structures at certain H coverage was also investigated.