Figure 4

UV/Vis absorption spectra and differential pulse voltammetry (DPV) potential of Pdn (n = 4 ~ 20) clusters.
(a) UV/Vis absorption spectra of Pdn (n = 4 ~ 20) clusters. (b) The UV/Vis absoption evolution of Pdn (n = 4 ~ 20) clusters. (c) The first oxidation (reduction) potential evolution of Pdn (n = 5 ~ 15) clusters. (d) The electrochemical and optic energy band gaps of Pdn (n = 4 ~ 15) clusters.