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 H 2 O 2, and Prussian blue nanoparticles (PB-NPs) synthesized in ionic liquid are used as the second electrocatalyst for the 2e-reduction of the produced H 2 O 2 into H 2 O 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 H 2 O 2 and H 2 O 2 into H 2 O. 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.