Synthesis And Optimization Of Oxygen Reduction Reaction(ORR) At Cathode Side Of Direct Methanol Fuel Cell

摘要

Currently, platinum is used as a cathode catalyst in DMFC, but it reduces the active sites for ORR and is very expensive. Moreover, ORRs have two pathways: 2 and 4 electron transfers. 4 electron transfers are preferred as they form water rather than hydrogen peroxide, which is toxic. Thus, an investigation of a non-Pt catalyst with 4 electron transfer is essential. This study proposes cobalt phthalocyanine/carbon-tungsten oxide nanowires or W18O49 as a non-Pt catalyst for the cathode side of DMFC. The factors involved in the screening of significant parameters were: the synthesis method, pyrolysis temperature, ratio of CoPc to carbon, ratio of CoPc/C to tungsten hexachloride and molarity of tungsten hexachloride. From ANOVA, two numeric factors and one categoric factor were selected for further optimization using RSM, while the other two factors were kept constant. Four responses were selected for RSM. The optimum parameters were determined to be the following: temperature at 600 °C , ratio of CoPc/C:WC16 of 1.90. These conditions produced a peak potential at 0.63 V vs. RHE, a mass activity at 0.65 V of 1.76 A gcatalyst-1, an average 3.9 electron transfer number to produce water as the main product, and an electron transfer at 0.65 V of 3.9. Finally, the results show that W18O49 has similar characteristics as platinum and is cheaper in price.