Nanorods of cerium oxide as an improved electrocatalyst for enhanced oxygen reduction in single-chambered microbial biofuel cells

Abstract

This paper reports the synthesis and utilization of cerium oxide (CeO _2 ) nanorods as a cathode catalyst and a potential, low-cost replacement of platinum for microbial biofuel cells (MBFCs). The nanorod electrocatalyst had exhibited significant improvements over Pt nanoparticles in terms of forward and backward onset potentials and peak current densities, electronic conductivity, charge transfer resistance, stability in 0.1 M phosphate buffer solution, and cost. It had also demonstrated a more stable forward peak current density at the 100th steady cycle, as well as, higher current density values up to 7,200 s. In addition, the synthesized CeO _2 nanorods also produced ∼10 ^3 times higher exchange current density over the synthesized Pt nanoparticles. Furthermore, in a single-chamber MBFC, the CeO _2 nanorods exhibited higher open circuit voltage (+0.80 V after 14 days), and output current (3613 mAm ^−2 at +0.3 V) and power (1084 mWm ^−2 ) densities in comparison to Pt nanoparticles.

Keywords

• microbial biofuel cell
• oxygen reduction reaction
• cathode catalyst
• unsupported catalyst
• cerium oxide nanorods