Effect of gold nanoparticles on the electrocatalytic reduction of oxygen by silica encapsulated cobalt phthalocyanine

Electrocatalysts based on mercaptopropyl functionalized mesoporous silica supported cobalt phthalocyanine (MPS-CoPc) are prepared by co-condensation of 3-mercaptopropyltriethoxysilane and tetraethyl orthosilicate in the presence of cetyltrimethylammonium bromide as a templating agent followed by incorporation of cobalt phthalocyanine (CoPc). Further, gold nanoparticles (Au NPs) are introduced into/onto the MPS-CoPc materials (i.e. Au-MPS-CoPc). Transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and UV–vis diffuse reflectance are employed to investigate structural and physical properties of catalysts. The electrocatalytic behavior of the above materials for dioxygen reduction is evaluated by cyclic voltammetry (CV). The CV results show that the MPS-CoPc and Au-MPS-CoPc modified electrodes are highly active towards the electrocatalytic oxygen reduction. With the incorporation of Au NPs, significant increase in current and considerable decrease in oxygen reduction potential is observed.