Porous Nickel Fibers with Enhanced Electrocatalytic Activities on Electro-oxidation of Ethanol in Alkaline Media

Abstract

Well-dispersed mesoporous nickel fibers with large specific surface areas were first reported as anode catalysts for the electro-oxidation of ethanol. The porous nickel fibers could be obtained by an easily controlled and template-free coordination precipitation-thermal deposition method using NiCl2 6H2O and oxalic acid as the raw materials and ammonia as the complexing and morphology-controlling agent. The method was low cost and suitable for mass production. The resulting nickel material showed a significant advantage of the hierarchical porous structure with fibrous morphology and a large specific surface area of 7.9\xa0m2\xa0g−1. The nickel fibers/GCE exhibited significantly higher electrocatalytic peak current density of 63\xa0mA\xa0cm−2 with a lower Tafel slope of 58.7\xa0mv\xa0dec−1. It also showed lower charge transfer resistance in the presence of ethanol (c\u2009=\u20090.2\xa0mol\xa0L−1) compared with those of the purchased spherical nickel powders. The superior electrocatalytic performance makes the as-prepared mesoporous fibers promising candidates for electrochemical catalyst materials in direct alkaline ethanol fuel cells (DAEFCs).