Yttrium Copper Titanate as a Highly Efficient Electrocatalyst for Oxygen Reduction Reaction in Fuel Cells, Synthesized via Ultrafast Automatic Flame Technique (original) (raw)

Replacing platinum (Pt) metal-based electrocatalysts used in the oxygen reduction reaction (ORR) in fuel cells is an important research topic due to the high cost and scarcity of Pt, which have restricted the commercialization of these clean-energy technologies. The ABO 3-type perovskite family of an ACu 3 Ti 4 O 12 (A = Ca, Y, Bi, and La) polycrystalline material can serve as an alternative electrocatalyst for the ORR in terms of low-cost, activity, and stability. These perovskite materials may be considered the next generation electro-catalyst for the ORR because of their photocatalytic activity and physical and chemical properties capable of containing a wide range of A-and B-site metals. This paper reports the ORR activity of a new Y 2/3 Cu 3 Ti 4 O 12 perovskite, synthesized via a rapid and facile automatic flame synthesis technique using rotating disk electrode (RDE) measurements. Y 2/3 Cu 3 Ti 4 O 12 /C has superior ORR activity, stability, and durability compared to commercial Pt/C. The results presented in this article will provide the future perspectives to research based on ACu 3 Ti 4 O 12 (A = Ca, Y, Bi, Sm, Cd, and La) perovskite as the next generation electro-catalyst for the ORR in various electrochemical devices, such as fuel cells, metal-air batteries, and electrolysis. Fuel cells (FCs) are a new power source via the direct conversion of hydrogen to electricity as a potential replacement for Li-ion batteries systems in terms of safety, high efficiency, renewable sources, and environmental friendliness 1. The major obstacle to the commercialization of fuel cells is the high cost, poor stability, and slow kinetics of the oxygen reduction reaction (ORR) of platinum and platinum-based electrocatalysts in fuel-cell electrodes 2. Thus far, the best electrocatalysts for the ORR of the cathode are carbon-supported Pt and/or its composites 3-8. High cost and scarcity of platinum requires either use of noble metal with an increased efficiency or the utilization of non-precious electrocatalysts for commercialization on a large scale. In addition, Pt-based electrocatalysts suffer from methanol crossover and CO poisoning 9. The ORR is not only an essential electrochemical process in fuel cells, but is also required for other electrochemical technologies, such as metal-air batteries and water electrolysis 10. The ORR takes place through multiple electron transfer in alkaline media. Depending on the nature and electrocatalytic activity of the catalysts, the ORR in alkaline media can occur either via a two electron process to produce HO 2 − or a four electron process to produce OH − (O 2 + 2H 2 O + 4e − → 4OH −) 11. A high ORR overpotential has been the main obstacle to making these technologies viable. Therefore, major efforts have been made to discover cost-effective and efficient ORR catalysts in traditional aqueous media. A general model of the oxygen reduction kinetics in porous electrodes must include oxygen diffusion, oxygen adsorption, or surface reaction on the active sites of the catalyst, charge transfer, and the diffusion of products 12. ABO 3 type perovskite oxides, particularly ACu 3 Ti 4 O 12 (A = Ca, La, Bi, Sm, Cd, and Y), have great potential as low cost, high stability, and better kinetics electro-catalyst and may be considered the next generation electro-catalyst for the ORR because of