Electroless synthesis of nanostructured nickel and nickel-boron tubes and their performance as unsupported ethanol electrooxidation catalysts

Considering the low abundance of platinum group metals and the high catalytic performance of nickel for the oxidation of small organic molecules, nickel catalysts are promising substitutional materials for direct alcohol fuel cells. Despite the simplicity, good scalability and flexibility of electroless plating, reports on the fabrication of nickel-based catalysts with this method are rare, in particular regarding the deposition of pure nickel. To expand the existing synthetic repertoire, we developed an electroless plating bath allowing the homogeneous deposition of spiky nickel films on very complex shaped substrates. Nanostructured nickel and nickel boron tubes were obtained by combination of the new and a borane-based plating reaction polymer templates, respectively. The composition, morphology and crystallinity of the products was comprehensively investigated with X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). Finally, the nickel and nickel boron tubes were applied as unsupported electrocatalysts for the oxidation of ethanol (EtOH) in alkaline environment. Compared to a macroscopic reference, both of the nanostructured catalysts showed improved utilization of high EtOH concentrations and considerably increased oxidation activities, rendering the applied deposition reactions promising routes towards novel catalysts for direct alcohol fuel cells. (C) 2012 Elsevier B.V. All rights reserved.