MoO3/C-supported Pd nanoparticles as an efficient bifunctional electrocatalyst for ethanol oxidation and oxygen reduction reactions

metal oxide electronic interactions in composite electrocatalysts have a considerable impact on their catalytic capability. In this study, we successfully synthesized an electrocatalytic material composed of MoO 3 /C species-supported Pd nanoparticles (Pd-MoO 3 /C) using a convenient hydrothermal method, which exhibited excellent catalytic activities for both ethanol oxidation and oxygen reduction in KOH media. The specific activity of Pd-MoO 3 /C toward ethanol oxidation with MoO 3 loading (40 wt%) was ~ 2.6 times greater than that for the commercial Pd/C (10 wt%) with the same Pd content. In particular, the activity could effectively hold up to ~ 60% of its maximum activity after 500-cycle tests, demonstrating improved cyclical stability. Notably, the fast electron transfer kinetics toward oxygen reduction for Pd-MoO 3 /C (40%) were also comparable to those of commercial Pt/C (20 wt%) catalysts. These superior electrochemical features are primarily derived from the stronger electronic coupling between Pd and MoO 3 through charge transfer, which can supply more active centers and improve the anti-poisoning ability. Meanwhile, the MoO 3 species in the Pd-MoO 3 /C composite may provide additional benefits in terms of electrical conductivity and dispersion. Graphical Abstract