High Catalytic Activity of Carbon Supported PdCu Alloyed Catalysts toward Oxygen Reduction Reaction

Abstract

The carbon supported PdCu alloyed catalysts (PdCu/C) with different molar ratios of Cu to Pd (Cu/Pd), namely, Cu/Pd=2.0, 3.0, 4.0, and 5.0, were synthesized by a simple and facile two-step method. The Cu nanoparticles were first obtained by microwave assisted method, and then followed by galvanic substitution of Pd on Cu nanoparticles. The PdCu/C catalysts exhibited mainly cubic phase with the average crystallite sizes ranging 4.0~4.5 nm by varying the Cu/Pd ratios of 2.0~5.0. The microstructure and the activity toward oxygen reduction reaction (ORR) of PdCu/C were significantly influenced by the Cu/Pd ratios. The higher degree of alloying and better ORR activity could be achieved with the Cu/Pd=4.0. The half-wave potential (E1/2) reached 0.760 V in the acid medium, which was only 40 mV lower than that of commercial Pt/C. Only 20 mV (2.6%) decrease in E1/2 after 1000 cycles between 0.4 and 1.0 V suggested the good stability.