Effective carbon nanotube supported metal (M=Au, Ag, Co, Mn, Ni, V, Zn) core Pd shell bimetallic anode catalysts for formic acid fuel cells

Abstract

At present, CNT supported Pd and core-shell Pd-based catalysts are synthesized by employing the NaBH4 reduction method to investigate on formic acid electrooxidation (FAEO) activity. These catalysts are characterized by XRD, TEM, HRTEM, and XPS. The XRD results display that the electronic state of catalysts changed by second metal addition to Pd. TEM results reveal that Au and Pd are homogeneously distributed. XPS results of AucorePdshell/CNT catalyst show that Au and Pd atoms used in the preparation of the catalyst are obtained mainly in elemental state. The FAEO activity, stability, and resistance of these catalysts are investigated by employing cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The CV results show that AucorePdshell/CNT catalyst having 16.42 mAcm−2 specific activity and 4978.23 mA mg−1 Pd mass activity is better than other catalysts. In addition, the AucorePdshell/CNT (21 m2/g) catalyst has better electrochemical active surface area (ECSA) value as 5.25 times compared with Pd/CNT catalyst. Direct formic acid fuel cell (DFAFC) performances are performed at different temperatures for AucorePdshell/CNT and NicorePdshell/CNT catalysts. The specific activity of AucorePdshell/CNT catalyst is 2.5 times higher than the value for NicorePdshell/CNT catalyst. AucorePdshell/CNT catalyst is a promising catalyst for DFAFCs.