High Performance Pd-CeO₂₋Nanorods/G Catalyst for the ORR and Its Application in a Microbial Fuel Cell

Abstract

Nanostructured Pd-CeO 2-NR /G, synthesized with NaBH 4 as reducing agent, was evaluated as cathode catalyst for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH and in a Microbial Fuel Cell (MFC) with pH=9.6. Previously, ceria nanorods (CeO 2-NR ) were synthesized by a hydrothermal method, while graphene (G) was obtained by mechanical milling. Morphological characterization showed agglomerated Pd nanoparticles and CeO 2-NR dispersed over graphene. Evaluation of catalytic activity for the ORR in half cell showed a higher mass activity of Pd-CeO 2-NR /G relative to Pd/C. The MFC was of the two-chamber type, separated by a Nafion(R) 117 membrane. In the anode, residual water directly from a pharmaceutical company (pH=9.6) was the electrolyte with an anode containing commercial Pt/C. The Bacilus Subtilis microorganism was used to form a biofilm over Pt/C and promote the bioelectrochemical reactions in N 2 atmosphere. In the cathode chamber, KOH with pH=9.6 was the electrolyte, which was saturated with O 2 . The polarization curves from the MFC demonstrated a higher catalytic activity of Pd-CeO 2-NR /G than Pd/C. The former delivered an open circuit voltage of 0.26 V and a maximum power density of 12.47 mW m -2 .

Key findings

• ▸Pd-CeO2-NR/G catalyst showed higher mass activity for ORR compared to Pd/C
• ▸The MFC with Pd-CeO2-NR/G cathode achieved higher power density compared to traditional catalysts
• ▸The use of Bacillus Subtilis microorganism promoted bioelectrochemical reactions in the MFC

Keywords

Identifiers

DOI

10.1149/ma2017-01/31/1491

Journal

ECS Meeting Abstracts

Year

2017