Thiolated graphene oxide-supported palladium cobalt alloyed nanoparticles as high performance electrocatalyst for oxygen reduction reaction

Abstract Thiolated graphene oxide-supported palladium cobalt alloyed catalyst has been synthesized by an electrochemical reduction method (denoted as ER/PdCo-tGO) for electrocatalytic oxygen reduction reaction (ORR). The polyethylene glycol (PEG) has been used as stabilizer for PdCo nanoparticles (NPs) stabilization. This material has been characterized by various instrumental methods. The morphological analysis shows the PdCo alloyed NPs are well set on to the thiolated graphene with better dispersion. The X-ray photoelectron spectroscopy (XPS) shows electrochemical reduction has been done successfully with the increasing C/O ratio from 0.88 to 2.14. Also, the X-ray diffraction (XRD) data reveals that the Co is presents with the oxidized form. The electrocatalytic activities have been verified using cyclic voltammetry (CV) and hydrodynamic voltammetry techniques in 0.1 M KOH electrolyte. The as prepared catalyst has shown better ORR onset potential (0.95 V vs. RHE) and superior mass activity (329 mA  mg P d − 1 at 0.8 V) which is 3.1 times higher than that of 20wt% Pt/C. The reaction kinetics have confirmed that the ORR at ER/PdCo-tGO catalyst follows a four electron transfer reaction process.