Single-crystalline ultrathin nanofilms of Ni aerogel with Ni(OH)2 hybrid nanoparticles towards enhanced catalytic performance for ethanol electro-oxidation

Abstract

Abstract In this study, we reported a novel and facile synthesis of self-supported three-dimensional (3D) Ni aerogel using cellulose hydrogel as template followed by removing the template under a moderate condition. The as-prepared Ni aerogel composed of Ni(OH)2 ultrathin nanofilms and Ni(OH)2 hybrid nanoparticles had hierarchical porous structure with a considerable specific surface area of 100 m2 g−1, which was beneficial to the enhanced catalytic activity towards ethanol electro-oxidation. Additionally, the self-supported 3D structure of Ni aerogel with free-carbon supports showed a positive effect on the stability of the catalysts. Electrochemical measurements revealed that a high peak current density for Ni aerogel achieved about 27.6 mA cm−2 in an electrolyte of 1.0 M KOH with 0.1 M ethanol, which was 5 times higher than that on alone Ni nanoparticles. Meanwhile, the Rct of Ni aerogel catalyst was only 0.88 Ω cm−2 after the CA measurements for 1800s, which was much smaller than commercial Ni nanoparticles and other similar catalysts reported. The enhanced electrocatalytic performance for ethanol electro-oxidation can be ascribed to the high surface area and predominant properties of above-mentioned special materials structure. This novel Ni aerogel and its excellent properties have great prospects in the application of electro-oxidation catalyst.