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- Xu, Zian, et al.
(författare)
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Hydrophobic-aerophilic composite catalysts enable the fast-charging Zn-air battery to operate 1200 h at 50 mA cm−2
- 2024
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Ingår i: Chemical Engineering Journal. - 1385-8947 .- 1873-3212. ; 481
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Tidskriftsartikel (refereegranskat)abstract
- High-efficient bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are central to Zn-air batteries (ZABs). However, the bifunctional activity of catalysts is still unsatisfactory, which restricts the fast-charge performance of ZABs. In this work, we constructed a hydrophobic-aerophilic bifunctional catalyst, where CoFe nanoparticles (NPs) and single atoms (SAs) are separately loaded on zeolite imidazolate fame (ZIF)-derived carbon and hollow carbon tubes respectively (CoFe NP@SA). Thereinto, CoFe SAs are known to be highly active to ORR reaction. Moreover, the in-situ Raman illustrates that CoFe NPs are transformed to CoOOH and FeOOH by electrochemical reconstruction, which can boost the OER activity. Furthermore, the hydrophobic-aerophilic surface can repel water molecules to create abundant solid–liquid-gas three-phase reaction interfaces and expose active sites, which consequently promote the diffusion of reactive molecules/ions across the interface and the oxygen adsorption. Thus, the CoFe NP@SA catalyst exhibit an ultralow ORR/OER potential gap of 0.6 V. After assembled as zinc-air battery (ZAB), it demonstrates a low charge potential (2.09 V) under a high current density of 50 mA cm−2 with the 1200-hour durability. This strategy paves the way to realize the high-power-density and fast-charging ZABs.
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| 2. |
- Chen, Shaoqing, et al.
(författare)
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Anchoring High-Concentration Oxygen Vacancies at Interfaces of CeO2–x/Cu toward Enhanced Activity for Preferential CO Oxidation
- 2015
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Ingår i: ACS Applied Materials & Interfaces. - 1944-8252 .- 1944-8244. ; 7:41, s. 22999-23007
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Tidskriftsartikel (refereegranskat)abstract
- Catalysts are urgently needed to remove the residual CO in hydrogen feeds through selective oxidation for large-scale applications of hydrogen proton exchange membrane fuel cells. We herein propose a new methodology that anchors high concentration oxygen vacancies at interface by designing a CeO2–x/Cu hybrid catalyst with enhanced preferential CO oxidation activity. This hybrid catalyst, with more than 6.1% oxygen vacancies fixed at the favorable interfacial sites, displays nearly 100% CO conversion efficiency in H2-rich streams over a broad temperature window from 120 to 210 °C, strikingly 5-fold wider than that of conventional CeO2/Cu (i.e., CeO2 supported on Cu) catalyst. Moreover, the catalyst exhibits a highest cycling stability ever reported, showing no deterioration after five cycling tests, and a super long-time stability beyond 100 h in the simulated operation environment that involves CO2 and H2O. On the basis of an arsenal of characterization techniques, we clearly show that the anchored oxygen vacancies are generated as a consequence of electron donation from metal copper atoms to CeO2 acceptor and the subsequent reverse spillover of oxygen induced by electron transfer in well controlled nanoheterojunction. The anchored oxygen vacancies play a bridging role in electron capture or transfer and drive molecule oxygen into active oxygen species to interact with the CO molecules adsorbed at interfaces, thus leading to an excellent preferential CO oxidation performance. This study opens a window to design a vast number of high-performance metal-oxide hybrid catalysts via the concept of anchoring oxygen vacancies at interfaces.
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