Mesoporous CuCo2O4 nanograsses as multi-functional electrodes for supercapacitors and electro-catalystsElectronic supplementary information (ESI) available. See DOI: 10.1039/c5ta00408j

Hierarchical, mesoporous CuCo 2 O 4 nanograsses have been synthesized on copper foam using a simple and cost-effective hydrothermal approach followed by a post-annealing treatment. The electrodes made from the novel nanoarchitecture exhibit multi-functional electrochemical performance. They deliver an excellent specific capacitance of 796 F g −1 at a current density of 2 A g −1 in a 2 M KOH aqueous solution and a long-term cyclic stability of 94.7% capacitance retention after 5000 cycles. When applied to electro-catalytic oxidation of methanol, the current density of the CuCo 2 O 4 /Cu foam electrode in 1 M KOH mixed with 0.5 M methanol is maintained up to 27.6 A g −1 . The superior electrochemical performances are mainly due to the unique one dimensional porous acicular architecture with a very large surface area and porosity grown on a highly conductive Cu substrate, offering faster ion/electron transfer, an improved reactivity and an enhanced structural stability. The fabrication strategy presented here is simple, cost-effective and scalable, which can open new avenues for large-scale applications of the novel materials in energy storage. A freestanding mesoporous CuCo 2 O 4 nanograss electrode exhibits a superior pseudocapacitive performance and a high electrocatalytic activity towards methanol oxidation.