Nanoporous PdFe alloy as highly active and durable electrocatalyst for oxygen reduction reaction

Nanoporous PdFe (NP-PdFe) alloy with uniform structure size and controllable bimetallic ratio was easily fabricated by one-step mild dealloying from PdFeAl precursor alloy. NP-PdFe consisted of nanoscaled interconnected network skeleton with bicontinuous hollow channels extending in all three dimensions. Compared with NP-Pd and commercial Pt/C catalysts, the NP-PdFe exhibits superior electrocatalytic activity for oxygen-reduction reaction (ORR) with enhanced specific and mass activities. Electrocatalytic measurements indicated that NP-PdFe possesses higher catalytic durability than Pt/C with the less loss of ORR activity and electrochemical active surface area upon long term potential scan. NP-PdFe alloy also shows higher methanol tolerance relative to Pt/C catalyst. XPS and DFT calculations suggest that the downshift of Pd d-band center after alloying with Fe makes favorable reaction kinetics for ORR with decreased adsorption energy of O and OH on Pd surface.