Glycerol-stabilized NaBH₄ reduction at room-temperature for the synthesis of a carbon-supported Pt_xFe alloy with superior oxygen reduction activity for a microbial fuel cell

Graphical abstract: - Highlights: • Glycerol is used as an efficient stabilizer and solvent to synthesis Pt_xFe alloy. • Pt_xFe alloy is prepared by simple two-step at room temperature;. • Pt₃-Fe/C show the best ORR catalytic performance in both acidic and neutral media;. • Pt_xFe alloy enhanced ORR activity and durability in microbial fuel cells. - Abstract: Insufficient catalytic activity and durability are the most challenging issues in the commercial deployment of low-temperature fuel cells. In an effort to address these barriers, three carbon-supported Pt_xFe alloy electrocatalysts with varying Pt:Fe atom ratios (Pt₃-Fe/C, Pt₂-Fe/C, Pt-Fe/C) were prepared by simple NaBH₄ reduction in glycerol at room temperature. All of the prepared Pt_xFe nanoparticles (NPs) are highly dispersed on a carbon support and show a single-phase face-centered cubic structure with a particle size of approximately 2 nm. The electrocatalytic performances of the synthesized Pt_xFe alloy catalysts were compared with that of commercial Pt/C by cyclic voltammetry and linear sweep voltammetry; among these NPs, the Pt₃-Fe/C catalyst exhibits the highest activity and the best stability for oxygen reduction reaction (ORR) in both acidic and neutral media. As the cathode catalyst, the maximum power density produced from microbial fuel cell with Pt₃-Fe/C (1680 ± 15 mW m⁻²) was 18% higher than that with conventional Pt/C (1422 ± 18 mW m⁻²), and the stability of Pt₃-Fe/C was greatly improved