Enhancement of Electrocatalytic Activity for Oxygen Reduction Reaction on TiO₂-Supported Pt-Based Intermetallic Compound Catalysts

Abstract

Stable and long-term electrocatalytic performance towards cathodic oxygen reduction reaction (ORR) was achieved by impregnation of Pt-based nanoparticles (NPs) on anatase titania (TiO 2 ) support. For example, organometallic precursors PtCODCl 2 and C 10 H 14 CuO 4 and TiO 2 or carbon black (CB) supports were co-reduced using lithium triethylborohydride to achieve intermetallic phase between Pt and Cu on TiO 2 (or CB) under ambient temperature. Finely dispersed PtCu NPs with an average particle size of 3 nm were achieved through wet-chemical synthetic route. Potential cycle with PtCu/CB in 0.1 M HClO 4 aqueous solution between 0.4-1.1 V ( vs. RHE) accelerates ORR (Fig. 1) because of the formation of dealloyed surface of PtCu NPs caused by dissolution of Cu from the surface of PtCu NPs. The dealloyed PtCu/CB showed the highest electrocatalytic activity both in terms of onset potential as well as cathodic current density compared to Pt/CB as well as PtPb/CB and PtNi/CB towards ORR (Fig. 2). The onset potential of PtCu/TiO 2 is shifted to higher electric potential by 180 mV compared to Pt/CB (Fig. 3).