Enhancement of the Electrocatalytic Reduction of Oxygen at Tungsten Oxide Modified Carbon-Supported RuSex Nanoparticles and Co-Porphyrin Centers

Introduction of carbon-supported RuSex nanoparticles or cobalt protoporphyrin into ultra-thin WO3 matrices results in the enhancement of their electroctalytic properties towards electroreduction of dioxygen in acidic medium (0.5 mol dm-3 H2SO4). The enhancement effects are evidenced from the positive shifts of the O2 reduction potentials (ca 150 mV and 200mV, respectively). An important issue is that the mixed-valent tungsten (VI, V) oxide support is characterized by good electronic and protonic conductivities. Further, not only RuSex and/or cobalt protoporphyrin are catalytic but also the tungsten oxide matrix is reactive: it provides protons and is capable of promoting the reduction of hydrogen peroxide intermediate.