Facile synthesis of Pd supported on Shewanella as an efficient catalyst for oxygen reduction reaction

Abstract

While noble metals loaded on carbon-based supports are commonly used as oxygen reduction catalysts for fuel cell cathodes, the preparation process is complicated and expensive cost. In this paper, Pd2+ was first adsorbed on Shewanella by its adsorption characteristics, then the Pd supported on Shewanella catalyst was obtained after carbonization at 600 °C and hydrogen reduction at 200 °C. The Shewanella cells retain the rod shape of bacteria following pyrolysis under high temperatures, while N and Pd heteroatoms are uniform distribution on the carbon matrix. As a result, Pd supported on Shewanella catalyst exhibits excellent electrocatalytic activity for ORR via a dominant four-electron oxygen reduction pathway in alkaline medium. More importantly, the mass activity of the prepared catalyst was 5.8 times higher than that of commercial Pd/C, and its stability was also better than the Pd/C, which could be promising alternatives to costly Pt-based electrocatalysts for ORR.