Hollow Sodium Nickel Fluoride Nanocubes Deposited MWCNT as An Efficient Electrocatalyst for Urea Oxidation

Abstract

Hollow nanocubes of sodium nickel fluoride deposited on multiwall carbon nanotubes (SNF-MWCNT) have been synthesized by a facile microwave assisted process using in situ templated mechanism. Ionic liquid (IL) played an important role in synthesizing the catalysts. Physicochemical properties of the catalysts were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The catalysts were analyzed for urea electrooxidation using cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) tests. The SNF-MWCNT electrocatalyst exhibited a very high current density of 3.12A cm(-2) mg(-1) at 20 mV s(-1) in 0.33 M urea and 5 M KOH solution aided by their Ni3+ rich surfaces, a porous and hollow structure and a favorable electronic effect of fluorine. The catalytic activity of SNF-MWCNT for urea oxidation was found superior than the commercially available Ni-C catalyst. The direct urea/air unit fuel cell showed a very promising performance by using SNF-MWCNT-5 mL IL as anode catalyst with a low amount of loading. (C) 2017 Elsevier Ltd. All rights reserved.