Unveiling a novel uranate nanocomposite: g-C3N4/UO3.NH3.H2O, ammonia atmosphere-based preparation and enhancement in electrochemical hydrogen storage capacity

Abstract

With depletion of fossil energy sources, the need of fuel has become a fundamental concern for humanity. Thus, the demand for nanostructured composites with enhanced electrochemical performance for hydrogen storage has been emerging. Herein, ammonium uranate-loaded g-C3N4 nanocomposites have been successfully prepared in an ammonia atmosphere, based on a simple, low-cost and one-step hydrothermal method. Further, to study the effect of increasing of the UO3 nanoparticles on the hydrogen storage ability of graphitic carbon nitride, the g- C3N4/UO3.NH3.H2O nanocomposites in two ratios, 10:1 (CN10U) and 3:1 (CN3U), were utilized for fabricating the working electrode of electrochemical cell. The chronopotentiometry measurements in an aqueous 6 M KOH electrolyte under 1 mA current showed high capacity for CN10U sample, 4510 mAhg???? 1, after 20 cycles. The Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) results which exhibited high specific surface area and pore volume along with the increased active sites, as well as the electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) data, indicating the reduced charge transfer resistance and improved kinetic performance, and high cyclic stability, respectively, support the superior storage capacity of CN10U compared to the other samples. Such a discharge capacity revealed the role of UO3 as a catalyzing material to increase the potential of g-C3N4 in hydrogen storage process. On this basis, the current study introduce the novel nanocomposite derived from ammonium uranate (AU) decorating on graphitic C3N4 as a good candidate for hydrogen storage.