Chandrasekharan Meenu P, Roy S. Electro-oxidation Reaction of Methanol over Reducible Ce
1-x-yNi
xSr
yO
2-δ: A Mechanistic Probe of Participation of Lattice Oxygen.
ACS APPLIED MATERIALS & INTERFACES 2023. [PMID:
37471142 DOI:
10.1021/acsami.3c05262]
[Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
Methanol oxidation reaction crucially depends on the formation of -OOH species over the catalyst's surface. Ni-based catalysts are by far the choice of materials, where the redox couple of Ni2+/Ni3+ facilitates the formation of -OOH species by surface reconstructions. However, it is challenging to oxidize Ni2+ as it generates charge-transfer orbitals near the Fermi energy level. One possible solution is to substitute Ni2+ with a reducible oxide support, which will not only facilitate the Ni2+ → Ni3+ oxidation but also adsorb oxygenated species like -OOH at a lower potential owing to its oxophilicity. This work shows with the help of structural and surface studies that the reducible CeO2 support in Ni and Sr co-doped Ce1-x-yNixSryO2-δ solid solution can easily facilitate Ni2+ → Ni3+ oxidation as well as evolution of lattice oxygen during the methanol oxidation reaction. While the Ni3+ species helped in formation of -OOH surface intermediates, the evolved lattice oxygen eased the CO oxidation process in order to bring out the better CO-tolerant methanol oxidation activity over Ce1-x-yNixSryO2-δ. The study shows the unique importance of the electronic interactions between the active site and support and involvement of lattice oxygen in the methanol oxidation reaction.
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