Cost-effective ion-tuning of Birnessite structures for efficient ORR electrocatalysts. (11th June 2020)

• Record Type: Journal Article
• Authors: Ochirkhuyag, Altantuya; Varga, Tamás; Tóth, Ildikó Y.; Varga, Ágnes Tímea; Sápi, András; Kukovecz, Ákos; Kónya, Zoltán
• Is Part Of: International journal of hydrogen energy. Volume 45:Number 32(2020)
• Page Start: 16266
• Page End: 16276
• Publication Date: 2020-06-11
• Subjects: Birnessite -- Interlayer cation -- Electrochemistry -- Catalyst -- ORR; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2020.04.022
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Birnessite structured MnOx with tuned potassium, copper and water content in the interlayer spacing is produced by a simple and cost-effective method. The new structures are investigated by XRD, Raman spectroscopy, SEM, EDX, HRTEM, DLS, TG, and DSC. Our study demonstrates a successful intercalation process to produce birnessites with mixed interlayer cations. Both Birnessite and Cu 2+ /Birnessite structure have a nanosheet-like morphology where the sizes of the copper-treated birnessite nanoparticles are drastically decreased compared to the copper ion free structures. The specific surface area is increased from 21.6 m 2 /g to 77.8 m 2 /g in the presence of copper as a result of a longer ageing process. Our study reveals that the electron transfer numbers of Birnessite and Cu 2+ /Birnessite are about 3.40 and 3.65, respectively in the oxygen reduction reaction. Both as-synthesized pristine Birnessite and copper tuned Birnessite are a promising candidate for a cheap, noble metal-free electrocatalyst for fuel cell applications. Highlights: K-, Cu-Birnessite nanostructures by cheap oone pot method for ORR. Birnessite showed high activity in ORR with the 4-electron pathway. Cu effecting the Mn 3+ /Mn 4+ ratio resulting in good ORR activity.