Evaluation of mixed transition metal (Co, Mn, and Cu) oxide electrocatalysts anchored on different carbon supports for robust oxygen reduction reaction in neutral media.

Autor: Khater DZ; Chemical Engineering & Pilot Plant Department, Engineering Research Institute, National Research Centre 33 El-Buhouth St., Dokki Cairo 12311 Egypt kamelced@hotmail.com., Amin RS; Chemical Engineering & Pilot Plant Department, Engineering Research Institute, National Research Centre 33 El-Buhouth St., Dokki Cairo 12311 Egypt kamelced@hotmail.com., Mahmoud M; Water Pollution Research Department, National Research Centre 33 El-Buhouth St., Dokki Cairo 12311 Egypt., El-Khatib KM; Chemical Engineering & Pilot Plant Department, Engineering Research Institute, National Research Centre 33 El-Buhouth St., Dokki Cairo 12311 Egypt kamelced@hotmail.com.
Jazyk: angličtina
Zdroj: RSC advances [RSC Adv] 2022 Jan 14; Vol. 12 (4), pp. 2207-2218. Date of Electronic Publication: 2022 Jan 14 (Print Publication: 2022).
DOI: 10.1039/d1ra07721j
Abstrakt: Oxygen reduction reaction (ORR) remains a pivotal factor in assessing the overall efficiency of energy conversion and storage technologies. A promising family of ORR electrocatalysts is mixed transition-metal oxides (MTMOs), which have recently gained a growing research interest. In this study, we developed MTMOs with different compositions (designated as A x B 3- x O 4 ; A = Cu, B = Co or Mn) anchored on two different carbon supports (activated carbon Vulcan XC-72 (AC) and graphene (G)) for catalyzing ORR in neutral media. Four different MTMO electrocatalysts ( i.e. , MnO 2 -CuO/AC, CoO-CuO/AC, CoO-CuO/G, and MnO 2 -CuO/G) were synthesized by a simple and scalable co-precipitation method. We documented the morphology and electrocatalytic properties of MTMO electrocatalysts using transmission and scanning electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), energy dispersive X-ray (EDX), and electrochemical techniques. Generally, MTMOs exhibited remarkably high ORR electrocatalytic activity with MTMOs anchored on an activated carbon support outperforming their respective MTMOs anchored on a graphene support, highlighting the importance of the catalyst support in determining the overall ORR activity of electrocatalysts. MnO 2 -CuO/AC has the highest diffusion limiting current density ( j ) value of 4.2 mA cm -2 at -600 mV ( vs. SHE), which is ∼1.1-1.7-fold higher than other tested electrocatalysts ( i.e. , 3.9, 3.5, and 2.7 mA cm -2 for CoO-CuO/AC, CoO-CuO/G, and MnO 2 -CuO/G, respectively), and slightly lower than Pt/C (5.1 mA cm -2 ) at the same potential value. Moreover, all electrocatalysts exhibited good linearity and parallelism of the Koutechy-Levich (K-L) plots, suggesting that ORR followed first-order reaction kinetics with the number of electrons involved being close to four. Benefiting from their remarkable ORR electrochemical activities and low cost, our results reveal that non-precious MTMOs are efficient enough to replace expensive Pt for broad applications in energy conversion and electrocatalysis in neutral media, such as microbial fuel cells.
Competing Interests: There are no conflicts to declare.
(This journal is © The Royal Society of Chemistry.)
Databáze: MEDLINE
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