A binder-free paper electrode with high performance for NaBH4 oxidation

Abstract

In this study, a piece of filter paper with good flexibility and hygroscopicity was used to support catalysts after a pencil drawing process. A layer of thin Ni film was deposited on the surface of the conductive graphite layer using an electrochemical method at a negative potential. Pd nanoparticles with high electrocatalytic activity for NaBH₄ oxidation were introduced by immersing the Ni film-graphite-filter paper (NGF) in PdCl₂ solution to obtain a Pd-NGF (PNGF) electrode. The morphology and phase structure of PNGF were characterized using scanning electron microscopy (SEM) equipped with an energy dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM) and an X-ray diffractometer (XRD). The PNGF electrode was used as the anode in direct borohydride fuel cells (DBFCs), and the electrochemical properties for NaBH₄ oxidation were determined by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). The oxidation current density reaches 550 mA cm⁻² at −0.4 V when the electrolyte contains 2 mol dm⁻³ NaOH and 0.10 mol dm⁻³ NaBH₄.