In this study, carbon nanotube (CNT) supported Pd50Co50, Pd50V50, Pd50Mn50, and Pd50Zn50 bimetallic catalysts are prepared by using sodium borohydride (NaBH4) reduction method to investigate their formic acid electrooxidation (FAEO) activities. These catalysts are characterized by using X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES), and X-ray Photoelectron Spectroscopy (XPS). The XRD results show that the electronic state of catalysts varied by second metal addition to Pd. TEM results reveal that Pd and Co are homogeneously distributed. The result of Pd43Co57/CNT obtained by ICP-OES analysis of Pd50Co50/CNT catalyst shows that the synthesis was successfully synthesized. XPS results of Pd50Co50/CNT and Pd50Zn50/CNT catalysts showed that Pd, Zn, and Co atoms used in the preparation of the catalysts were obtained mainly in their elemental state. In addition, FAEO activity and stability of these catalysts are examined by using cyclic voltammetry (CV) and chronoamperometry (CA). Pd50Co50/CNT indicated the highest specific and mass activities with 6.89 mA/cm(2) and 649.69 mA/mg Pd, respectively. Direct formic acid fuel cell (DFAFC) performances are performed in different temperatures for Pd50Co50/CNT catalyst. The specific current for DFAFC performance of this catalyst was evaluated as 5.71, 6.87, and 2.43 mA/cm(2) at 18 degrees C, 30 degrees C, and 60 degrees C cell temperature at 0.5 V, respectively. (C) 2019 Elsevier B.V. All rights reserved.