Unveiling the origin of catalytic sites of Pt nanoparticles decorated on oxygen-deficient vanadium-doped cobalt hydroxide nanosheet for hybrid sodium-air batteries

Kang, Yao, Wang, Shuo, Liu, Yanyu, Hui, Kwan San, Li, Haifeng, Ng, Kar Wei, Liang, Feng, Geng, Jianxin, Hong, Xiaoting, Zhou, Wei and Hui, Kwun Nam (2020) Unveiling the origin of catalytic sites of Pt nanoparticles decorated on oxygen-deficient vanadium-doped cobalt hydroxide nanosheet for hybrid sodium-air batteries. ACS Applied Energy Materials, 3 (8). pp. 7464-7473. ISSN 2574-0962

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Abstract

Highly active bifunctional electrocatalysts are crucial for improving the performance of rechargeable metal-air batteries. However, most reported bifunctional electrocatalysts feature poor electrocatalytic activity and stability toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Here, we have reported the first-ever study of an effective one-step reduction-assisted exfoliation method to exfoliate bulk vanadium-doped cobalt hydroxide (V-doped Co(OH)2, denoted as V-Co(OH)2) into ultrathin nanosheets with abundant oxygen vacancies (V-Co(OH)2-Ov) and simultaneously anchor them with highly dispersed ultrafine Pt nanoparticles (NPs) with a nominal size of 0.8-2.4 nm (denoted as Pt/V-Co(OH)2-Ov). The Pt/V-Co(OH)2-Ov catalyst exhibits improved catalytic performance in ORR/OER. X-ray absorption spectroscopy analysis and theoretical calculations reveal the strong interfacial electronic interactions between Pt NPs and V-Co(OH)2-Ov, which synergistically improves oxygen intermediates' adsorption/desorption, enhancing the ORR and OER performance. Using Pt/V-Co(OH)2-Ov as a catalyst in the air cathode, a hybrid sodium-air battery displays a record value of an ultralow charging-discharging voltage gap of 0.07 V at a current density of 0.01 mA cm-2 with remarkable stability of up to 1000 cycles. This reduction-assisted exfoliation approach provides a new strategy to generate oxygen vacancies in metal hydroxides, which act as anchoring sites for deposition of sub-nanometal NPs via a strong interfacial effect.

Item Type: Article
Uncontrolled Keywords: dft calculation,electrocatalysis,electronic structure reformation,hybrid sodium-air battery,pt nanoparticles,vanadium-doped cobalt hydroxide,chemical engineering (miscellaneous),energy engineering and power technology,electrochemistry,materials chemistry,electrical and electronic engineering ,/dk/atira/pure/subjectarea/asjc/1500/1501
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Depositing User: LivePure Connector
Date Deposited: 21 Oct 2020 23:55
Last Modified: 11 Oct 2021 00:53
URI: https://ueaeprints.uea.ac.uk/id/eprint/77394
DOI: 10.1021/acsaem.0c00872

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