Polyhedron shaped palladium nanostructures embedded on MoO2/PANI-g-C3N4 as high performance and durable electrocatalyst for oxygen reduction reaction

[Display omitted] •Polyhedron Pd nanoparticles with MoO2/PANI-g-C3N4 has excellent ORR performance.•Pd-O, Pd-OH and induced oxygen vacancy might enhance the active surface area.•N elements in catalyst enhances the synergistic effect between Pd and Mo metal.•The DFT results corroborates the key active components of the catalysts and their role for ORR. A hybrid catalyst support anchoring a noble metal catalyst could be a promising material for building interfacial bonding between metallic nanostructures and polymer functionalized carbon supports to improve the kinetics of oxygen reduction reaction (ORR). This study successfully prepared a polyhedron nanostructured Pd and MoO2-embedded polyaniline-functionalized graphitized carbon nitride (PANI-g-C3N4) surface using a chemical reduction method. The Pd–Mo/PANI-g-C3N4 achieved an ORR activity of 0.27 mA µg−1 and 1.14 mA cm−2 at 0.85 V, which were 4.5 times higher than those of commercial 20% Pt/C catalyst (0.06 mA µg−1 and 0.14 mA cm−2). In addition, the Pd–Mo/PANI-g-C3N4 retained ∼ 77.5% of its initial mass activity after 10,000 cycles, with only 30 mV half-wave potential reduction. Further, the engineered potential active sites in the catalyst material verified the significant improvement in the ORR activity of the catalyst with increased life-time, and theoretical calculations revealed that the synergistic effect of the catalytic components enhanced the ORR kinetics of the active sites.