Activity manifestation via architectural manipulation by cubic silica-derived Co3O4 electrocatalysts towards bifunctional oxygen electrode performance. (25th August 2021)

• Record Type: Journal Article
• Authors: Selvakumar, Karuppiah; Duraisamy, Velu; Senthil Kumar, Sakkarapalayam Murugesan
• Is Part Of: New journal of chemistry. Volume 45:Number 36(2021)
• Page Start: 16913
• Page End: 16925
• Publication Date: 2021-08-25
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/d1nj02061g
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : A KIT-6-derived Co3 O4 material demonstrates superior bifunctional activity due to its higher densities of Co 3+ and Co 2+ sites. Abstract : Electrocatalytic water splitting reaction utilizing non-renewable energy resources significantly leads to a sustainable energy infrastructure. Highly efficient bifunctional catalysts for oxygen reduction and oxygen evolution reactions (ORR/OER) are essential for the replacement of platinum, ruthenium and iridium metals. We used four different silica templates to create excellent mesoporous cobalt oxide (Co3 O4 ) electrocatalysts in crystalline form. Various advanced techniques confirm the spinel structure composed of both Co 3+ and Co 2+ sites, which lead to an enhanced surface area, mesoporosity, and a rod morphology with a cubic-like network structure. Among these replicas, the Mobil composition of matter (MCM)-48-derived Co3 O4 (Co3 O4 -M8) material demonstrates remarkable OER activity with an observed potential of 1.76 V, a Tafel slope of 107 mV dec −1 and a lower charge transfer resistance. Such a high performance is observed due to assistance of the Co 3+ to Co 4+ transition during the oxygen evolution reaction. The ORR was more active on the Korea advanced institute of science and technology (KIT)-6-derived Co3 O4 (Co3 O4 -K6) material, which displayed a more positive onset potential of 0.85 V, a half-wave potential of 0.56 V and a better current density in alkaline medium. In addition, we found that the stabilization of Co 2+ active sites in the Co3 O4 -K6 material is the reason for the enhanced oxygen reduction reaction. The observed bifunctional activity (Δ E = E OER @10 mA cm −2 − ORR@ E 1/2 ) for the Co3 O4 -K6 catalyst is 1.22 V, which shows significant performance among all the catalysts prepared in this work. Such an earth-abundant mesoporous Co3 O4 catalyst obtained via an environmentally benign process is anticipated to revolutionize electrochemical energy conversion and storage devices.