A Carbon-Particle-Supported Palladium-Based Cobalt Composite Electrocatalyst for Ethanol Oxidation Reaction (EOR)

For the first time, carbon-particle-supported palladium-based cobalt composite electrocatalysts (abbreviated as PdxCoy/CPs) were prepared using a calcination–hydrothermal process–hydrothermal process (denoted as CHH). The catalysts of PdxCoy/CPs prepared using CoC2O4·2H2O, (CH3COO)2Co·4H2O, and metallic cobalt were named catalyst c1, c2, and c3, respectively. For comparison, the catalyst prepared in the absence of a Co source (denoted as Pd/CP) was identified as catalyst c0. All fabricated catalysts were thoroughly characterized by XRD, EDS, XPS, and FTIR, indicating that PdO, metallic Pd, carbon particles, and a very small amount of cobalt oxide were the main components of all produced catalysts. As demonstrated by the traditional electrochemical techniques of CV and CA, the electrocatalytic performances of PdxCoy/CP towards the ethanol oxidation reaction (EOR) were significantly superior to that of Pd/CP. In particular, c1 showed an unexpected electrocatalytic activity for EOR; for instance, in the CV test, the peak f current density of EOR on catalyst c1 was 129.3 mA cm−2, being about 10.7 times larger than that measured on Pd/CP, and in the CA test, the polarized current density of EOR recorded for c1 after 7200 s was still about 2.1 mA cm−2, which was larger than that recorded for Pd/CP (0.6 mA cm−2). In the catalyst preparation process, except for the elements of C, O, Co, and Pd, no other elements were involved, which was thought to be the main contribution of this preliminary work, being very meaningful to the further exploration of Pd-based composite EOR catalysts.