Simple fabrication of pineapple root-like palladium-gold catalysts as the high-efficiency cathode in direct peroxide-peroxide fuel cells

Abstract

Pd-Au/TiC electrodes with various three-dimensional structures are obtained by the pulsed potential electro-deposition in PdCl2/HAuCl4 electrolytes. The morphologies of Pd-Au/TiC composite catalysts are significantly dependent on the component of deposited solutions. The surface appearance of Pd-Au catalysts changes from rime-shaped structure, to feather-like construction, then to pineapple root-like structure and finally to flower-like configuration with the increase of PdCl2 content in electrolytes. These particular three-dimensional structures may be very suitable for H2O2 electro-reduction, which assures a high utilization of Pd-Au catalysts and provides a large specific surface area. The electro-catalytic activities of H2O2 reduction on the Pd-Au/TiC electrodes improve as increasing the Pd content in Pd-Au alloy catalysts. The pineapple root-like Pd5Au1/TiC electrode reveals remarkably excellent electrochemical property and desirable stability for catalyzing H2O2 reduction in acid media. The direct peroxide-peroxide fuel cells with a 10 cm3 min−1 flow rate display the open circuit voltage (OCV) of 0.85V and the peak power density of 56.5mWcm−2 at 155mAcm−2 with desirable cell stability, which is much higher than those previously reported.