A Highly Efficient Co3O4 Nanoparticle-Incorporated Mesoporous Beta Composite as a Synergistic Catalyst for Oxygen Reduction

Graphical Upping the pace : A novel precious-metal-free cathode catalyst, Co 3 O 4 nanoparticle-incorporated m -Beta zeolite, is synthesized and used to speed up the sluggish oxygen reduction reaction through a synergistic catalytic effect. Cost-efficient and high-performance oxygen reduction electrocatalysts are widely pursued to boost the sluggish oxygen reduction reaction (ORR) for renewable-energy technology applications. Here, a novel precious-metal-free cathode catalyst, Co 3 O 4 nanoparticle-incorporated mesoporous Beta zeolite, was first synthesized by using a facile steam-assisted crystallization (SAC) and hydrothermal approach. Owning to the synergetic catalytic effects between the Co 3 O 4 nanoparticles and the mesoporous Beta matrix, the resulting Co 3 O 4 / m -Beta nanocomposites catalyst showed comparable ORR electrochemical catalytic activity to the benchmark 20 wt% Pt/C catalyst with a high onset potential of 0.88 V, and much higher methanol tolerance with a negligible negative shift of the peak potential and excellent electrochemical stability in alkaline media. The relatively higher surface Co 2+ concentration and the abundant Brønsted acid sites facilitate the ORR process, mainly through a 4e − pathway, which makes the Co 3 O 4 / m -Beta nanocomposite a favorable candidate for improving energy storage and conversion efficiencies in fuel cells.