Investigation of Biomass-Derived Heteroatom-Doped Carbon Fiber Aerogel Decorated with NiCo2S4 Flowers as a Binder-Free Anode for Urea Electrooxidation: From a Sustainable Standpoint

Abstract

The fabrication of proficient anodes for urea oxidation reaction (UOR) with the inherent traits including competent catalytic activity, enhanced electronic conductivity, sound durability, and low cost are the inevitable criteria for the advancement and practical implementation of green energy conversion devices, such as direct urea/urine fuel cells. Herein we are reporting the decoration of biomass-derived nitrogen-doped carbon fiber aerogel (NCFA) with three-dimensional (3D) flower-like NiCo2S4 (NCS) architectures fabricated via the one-step hydrothermal method and exploited as a binder-free anode for UOR. With concrete operational stability, the constructed NCS@NCFA (1:2) anode delivered an excellent current density of 166 mA cm–2 and 79 mA cm–2 in urea and human urine, respectively. This remarkable UOR activity of the NCS@NCFA (1:2) electrode is chiefly ascribed to the unique 3D open morphological feature, which triggers the maximum adsorption and momentous electrooxidation of urea. Moreover, the densely interconnected graphitized fibers not only inhabit the catalytic active structures but also facilitate the elevated anolyte transfer characteristics by their conductive open framework.