Oxygen Reduction Reaction on Pt/C Catalysts Prepared by Impregnation and Liquid Phase Photo-Deposition

摘要

Pt/C catalysts supported on carbon (5 wt. % Pt) synthesized by photo-deposition and impregnation methods were electrochemically evaluated in the oxygen reduction reaction. Platinum nanoparticles were prepared by photo-irradiation of Pt precursors (H_2PtCl_6 and C_(10)H_(14)O_4Pt) with UV-irradiation (365 nm) at room temperature. The photo-reduction of H_2PtCl_6 to metallic platinum (Pt~(4+)→Pt~(2+)→Pt~0) was faster than C_(10)H_(14)O_4Pt (Pt~(2+)→Pt~0) at the same operation conditions. The Pt/C samples were characterized by XRD, EDS, H_2 chemisorption, TEM, cyclic and linear voltammetry techniques. XRD and TEM/EDS studies showed that Pt particles synthesized with C_(10)H_(14)O_4Pt by the photo-deposition method were smaller with a higher dispersion on carbon than those prepared with H_2PtCl_6. A similar behavior was found when the impregnation method is used. The platinum particle size was smaller with C_(10)H_(14)O_4Pt as compared to H_2PtCl_6 precursor. The Pt/C catalyst synthesized with C_(10)H_(14)O_4Pt by thephoto-deposition method displayed a catalytic activity in the oxygen reduction reaction comparable to a commercial 10 wt. % Pt/C, ETEK catalyst.