In the case of the CuO/AgO, the percentage of each oxide was 5.9% CuO and 0.1% AgO, in order to attain the synergistic effect of both catalysts.Besides, a fifth dispersion was considered by adding just carboxylated MWCNTs without catalysts, to the PS solution, in order to study the possible electrocatalytic effect of the CNTs. In this case, the proportion of MWCNTs was equally 13.4% in the PS composite. Once dispersed in toluene, the mixture was further homogenized by gentle magnetic stirring overnight.