Performance assessment of a direct borohydride-peroxide fuel cell with Pd-impregnated faujasite X zeolite as anode electrocatalyst

Abstract

This work proposes a direct borohydride fuel cell (DBFC) with palladium (Pd)-impregnated faujasite X zeolite (PdX) as anodic electrocatalyst. The PdX was prepared by Pd ion exchange with Na ion within NaX zeolite and it was characterised by ICP-OES, FTIR, SEM-EDS, TEM and N2 sorption analysis. PdX was subsequently tested as electrocatalyst for borohydride (BH4−) oxidation reaction (BOR) using linear scan voltammetry with and without electrode rotation. For this purpose, sodium borohydride (NaBH4) solutions ranging between 0.01 and 0.06 M in alkaline medium were used. The reaction order for BH4− oxidation at PdX was determined to be close to 1. The PdX zeolite electrode showed high performance for BOR, as evidenced by 3–5 electrons exchanged, depending on NaBH4 concentration. A laboratory direct borohydride-peroxide fuel cell was assembled using a PdX anode and tested in the 25–45 °C temperature range, reaching power densities between 214 and 263 mW cm−2.