Novel methanol electro-oxidation catalyst assisting with functional phthalocyanine supports

Abstract

Novel electro-catalyst based on phthalocyanine stabilized Pt colloids has been developed for methanol electro-oxidation. Water soluble Cu 2+ phthalocyanine functioned with sulfonic groups were selected as catalyst supports because of the relatively high catalytic activity of Pt catalyst and nearly the same catalytic selectivity complex with Cu-phthalocyanine, compared to others that chelated with Fe, Co and Ni ions. The as-resulting Pt–CuTsPc catalysts have average particle size of 2 nm and narrow size distribution. With the assistance of CuTsPc supports, the methanol electro-oxidation activity and poison tolerance of Pt catalyst have a significant increase. I f/ I b ratio (anodic peak current density, forward to backward) of the Pt–CuTsPc/C catalysts also has obvious increase to 2.5, from value of 0.8 for pure Pt/C catalyst. The reaction Tafel slope of Pt-CuTsPc/C catalysts is 56.6 mV dec −1, much smaller than that of the Pt/C catalyst. The transient current density on Pt–CuTsPc/C at 0.60 V is enhanced to 650% of that on the Pt/C catalyst while the enhancement factor R for comparison of steady-state current obtained on Pt–CuTsPc/C and Pt/C catalyst varies between 111% and 534% in the potential region of 0.3–0.75 V.