Rational functionalization of carbon nanotube/ionic liquid bucky gel with dual tailor-made electrocatalysts for four-electron reduction of oxygen

Multiwalled carbon nanotube/ionic liquid bucky gel is rationally functionalized with dual tailor-made electrocatalysts to form novel kinds of structurally uniform and electrochemically favorable multifunctional materials that are very active for an apparent four-electron (4e) reduction of oxygen (O-2). Cobalt porphyrin (COP) dissolved into the bucky gel is used as the first electrocatalyst for the 2e-reduction of O-2 into H2O2, and Prussian blue nanoparticles (PB-NPs) synthesized in ionic liquid are used as the second electrocatalyst for the 2e-reduction of the produced H2O2 into H2O to evoke an apparent 4e-reduction of O-2 with a low overpotential. In this context, the bucky gel can not only serve as a reservoir to homogeneously culture the tailor-made electrocatalysts but also enhance the electrocatalytic activities of the cultured dual electrocatalysts toward the reduction of O-2 into H2O2 and H2O2 into H2O. The multifunctional materials prepared by rational functionalization of carbon nanotube/ionic liquid bucky gel with the dual tailor-made electrocatalysts are demonstrated to be very active for the 4e-reduction of O-2 and could thus be potentially used as a new kind of non-platinum cathode material for O-2 reduction in fuel cells. The strategy demonstrated here is cost-effective and may pave a relatively general approach to preparation of multifunctional materials with excellent properties and striking applications.