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Cr dopant regulating d-orbital electronic configuration of NiFe spinel oxide to improve oxygen evolution reaction in Zn-air battery.
- Source :
-
Journal of Alloys & Compounds . Jun2024, Vol. 987, pN.PAG-N.PAG. 1p. - Publication Year :
- 2024
-
Abstract
- Significant advancements towards enhancing the catalytic activity of spinel ferrites in oxygen evolution reaction (OER) have been achieved, however, further studies are required on this regard. In this study, Cr-doped spinel ferrite (NiFe 2 O 4) embedded in N-doped C (Cr-NiFe 2 O 4 @NC) was synthesized via a high-temperature treatment using an NiFe Prussian blue analog as a precursor and K 2 Cr 2 O 7 as a Cr source. Owing to the strong octahedral site preference energy, Cr3+ ions were successfully doped into octahedral sites and tailored the electronic configuration of NiFe 2 O 4 , as confirmed by XPS. The Cr-substituted Cr-NiFe 2 O 4 @NC exhibited the overpotential of 241 mV at 10 mA cm−2, which was smaller than that of NiFe 2 O 4 @NC (266 mV) at the same current density. Meanwhile, the Tafel slope of Cr-NiFe 2 O 4 @NC (65.32 mV dec−1) was also lower than that of NiFe 2 O 4 @NC (86.96 mV dec−1). Therefore, the Cr substitution can improve the electrocatalytic OER performance of NiFe 2 O 4 @NC. In particular, an assembled rechargeable Zn-air battery using Cr-NiFe 2 O 4 @NC as the cathode catalyst afforded a high power density (61.1 mA cm−2) together with a high specific capacity (740 mA g−1). Amazingly, it could power light-emitting diodes, demonstrating its real-world application. Density functional theory calculations revealed that Cr ion doping led to electron transfer in NiFe 2 O 4 , resulting in a density of electronic states close to the Fermi level, which probably regulated the adsorption/desorption behaviors of oxygenate intermediates (*O and *OOH), thus promoting the reaction kinetics of the OER. This study provides a helpful basis for the development of spinel oxides with high electrocatalytic OER activity and durability via cation doping. [Display omitted] • Cr-NiFe 2 O 4 @NC was prepared from NiFe Prussian blue analogue (NiFePBA). • The Cr dopant regulated d-band center position of NiFe2O4 for improving electrocatalytic OER activity. • The connection between Cr doping and OER activity was clarified by DFT. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09258388
- Volume :
- 987
- Database :
- Academic Search Index
- Journal :
- Journal of Alloys & Compounds
- Publication Type :
- Academic Journal
- Accession number :
- 176270655
- Full Text :
- https://doi.org/10.1016/j.jallcom.2024.174248