Carbon nanotube supported direct borohydride fuel cell anode catalysts: the effect of catalyst loading

Abstract

Energy, vital and permanent need for human life and welfare, supplied by fossil fuels such asoil, coal, and natural gas through the world has been rising gradually. However, the employmentof fossil fuels to supply energy need have several disadvantages such as shortage of fossil fuelsand global warming caused via fossil fuel exhaust gases. To eliminate these disadvantages offossil fuel consumption in energy generating systems, research studies are dedicated to thealternative energy sources such as fuel cells, batteries, solar energy, wind energy. Fuel cells arethe most popular alternative energy devices and attributed great importance to recompense therapidly increasing energy demand. Direct Borohydride Fuel Cells (DBFCs), known as a specialgroup of an alkaline direct liquid fuel cell (DLFC). At present, monometallic CNT supportedPd electrocatalysts (Pd/CNT) are prepared at varying Pd loadings via sodium borohydride(NaBH4) reduction method to investigate their NaBH4 electrooxidation activities. Thesemonometallic Pd/CNT catalysts are characterized by X-ray Diffraction (XRD), N2 adsorptiondesorption, X-ray photoelectron spectroscopy (XPS), and Scanning Electron MicroscopyEnergy Dispersive X-ray analysis (SEM-EDX). NaBH4 electrooxidation measurements areperformed with cyclic voltammetry (CV), chronoamperometry (CA), and electrochemicalimpedance spectroscopy (EIS). The 30% Pd/CNT catalyst exhibits the highest electrochemicalactivity. By altering Pd loading, catalyst surface electronic structure changes significantly,leading to enhanced NaBH4 electrooxidation activity. As a conclusion, it is clear that Pd/CNTcatalysts are good candidate as anode catalysts for direct borohydride fuel cells.