Nanoporous (Pt1−xFex)3Al intermetallic compounds for greatly enhanced oxygen electroreduction catalysis

Abstract

Considerable demand for the widespread commercialization of proton exchange membrane (PEM) fuel cells has stimulated intensive research into the development of oxygen electroreduction catalysts that are more efficient than carbon-supported Pt nanoparticles. Here we report a dealloyed ternary intermetallic compound of PtFeAl with a nanoporous structure composed of a (Pt_1−xFe_x)₃Al (x = 0.167) core with Pt skin [NP (Pt_1−xFe_x)₃Al/Pt]. As an oxygen reduction reaction catalyst, NP (Pt_1−xFe_x)₃Al/Pt exhibits exceptional durability in long-term electrochemical cycling, with specific and mass activities of 3.97 mA cm_Pt⁻² and 1.94 A mg_Pt⁻¹, respectively (∼10.2- and ∼14.9-fold higher than those of commercially available Pt/C). This is due to strong Pt–Al and Fe–Al bonds, which not only weaken the adsorption energy of the Pt skin but also inhibit the evolution of Pt, Fe and Al atoms. The outstanding performance makes this a promising candidate as a cathode catalyst in PEM fuel cells as well as in other electrochemical energy conversion and storage devices, such as metal–air batteries.