Remarkable activity of a ZnPdPt anode catalyst: Synthesis, characterization, and formic acid fuel cell performance

Abstract Herein, multi-walled carbon nanotube (MWCNT) supported Zn-Pd and Zn-Pd-Pt catalysts have been prepared utilizing a sequential sodium borohydride (SBH) reduction method. The resulting Zn/MWCNT, Zn-Pd/MWCNT, and Zn-Pd-Pt/MWCNT catalysts were characterized using advanced surface analytical techniques such as X-ray diffraction (XRD), high contrast transmission electron microscopy (C-TEM), and X-ray photoelectron spectroscopy (XPS). The characterization results indicate that the Zn/MWCNT, Zn-Pd/MWCNT, and Zn-Pd-Pt/MWCNT catalysts were successfully prepared. It was observed that Pd and Pt incorporation into Zn alters the electronic structure of Zn. Cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) were used to examine the electrochemical activity of the catalysts toward the electrooxidation of formic acid (FA). The results reveal that ZnPdPt/MWCNT has a specific activity of 12.6 mA/cm2 and an electrochemical active surface area (ECSA) of 41.1 m2/g. This catalyst shows high activity, stability, and resistance when compared to Pd/MWCNT and ZnPd/MWCNT. Direct FA fuel cell (DFAFC) measurements were performed at 18-60 oC for the ZnPd/MWCNT and ZnPdPt/MWCNT catalysts. The specific activity of ZnPdPt/MWCNT was 1.45 times greater than that measured for ZnPd/MWCNT. ZnPdPt/MWCNT is a promising catalyst according to our CV, CA, EIS, and DFAFC measurements.