Halide-Doping Effect of Strontium Cobalt Oxide Electrocatalyst and the Induced Activity for Oxygen Evolution in an Alkaline Solution
Perovskites of strontium cobalt oxyhalides having the chemical formulae Sr<sub>2</sub>CoO<sub>4-x</sub>H<sub>x</sub> (H = F, Cl, and Br; x = 0 and 1) were prepared using a solid-phase synthesis approach and comparatively evaluated as electrocatalysts for oxygen ev...
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2021-11-01
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| author | Mohamed A. Ghanem Mabrook S. Amer Abdullah M. Al-Mayouf Prabhakarn Arunachalam Mark T. Weller |
| author_facet | Mohamed A. Ghanem Mabrook S. Amer Abdullah M. Al-Mayouf Prabhakarn Arunachalam Mark T. Weller |
| author_sort | Mohamed A. Ghanem |
| collection | DOAJ |
| description | Perovskites of strontium cobalt oxyhalides having the chemical formulae Sr<sub>2</sub>CoO<sub>4-x</sub>H<sub>x</sub> (H = F, Cl, and Br; x = 0 and 1) were prepared using a solid-phase synthesis approach and comparatively evaluated as electrocatalysts for oxygen evolution in an alkaline solution. The perovskite electrocatalyst crystal phase, surface morphology, and composition were examined by X-ray diffraction, a scanning electron microscope, and energy-dispersive X-ray (EDX) mapping. The electrochemical investigations of the oxyhalides catalysts showed that the doping of F, Cl, or Br into the Sr<sub>2</sub>CoO<sub>4</sub> parent oxide enhances the electrocatalytic activity for the oxygen evolution reaction (OER) with the onset potential as well as the potential required to achieve a current density of 10 mA/cm<sup>2</sup> shifting to lower potential values in the order of Sr<sub>2</sub>CoO<sub>4</sub> (1.64, 1.73) > Sr<sub>2</sub>CoO<sub>3</sub>Br (1.61, 1.65) > Sr<sub>2</sub>CoO<sub>3</sub>Cl (1.53, 1.60) > Sr<sub>2</sub>CoO<sub>3</sub>F (1.50, 1.56) V vs. HRE which indicates that Sr<sub>2</sub>CoO<sub>3</sub>F is the most active electrode among the studied catalysts under static and steady-state conditions. Moreover, Sr<sub>2</sub>CoO<sub>3</sub>F demonstrates long-term stability and remarkably less charge transfer resistance (R<sub>ct</sub> = 36.8 ohm) than the other oxyhalide counterparts during the OER. The doping of the perovskites with halide ions particularly the fluoride-ion enhances the surface oxygen vacancy density due to electron withdrawal away from the Co-atom which improves the ionic and electronic conductivity as well as the electrochemical activity of the oxygen evolution in alkaline solution. |
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| spelling | doaj.art-182b774feb91414ea822adc99afb64b72023-11-22T22:46:47ZengMDPI AGCatalysts2073-43442021-11-011111140810.3390/catal11111408Halide-Doping Effect of Strontium Cobalt Oxide Electrocatalyst and the Induced Activity for Oxygen Evolution in an Alkaline SolutionMohamed A. Ghanem0Mabrook S. Amer1Abdullah M. Al-Mayouf2Prabhakarn Arunachalam3Mark T. Weller4Chemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi ArabiaChemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi ArabiaChemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi ArabiaChemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi ArabiaChemistry Department, Cardiff University, Cardiff CF10 3AT, UKPerovskites of strontium cobalt oxyhalides having the chemical formulae Sr<sub>2</sub>CoO<sub>4-x</sub>H<sub>x</sub> (H = F, Cl, and Br; x = 0 and 1) were prepared using a solid-phase synthesis approach and comparatively evaluated as electrocatalysts for oxygen evolution in an alkaline solution. The perovskite electrocatalyst crystal phase, surface morphology, and composition were examined by X-ray diffraction, a scanning electron microscope, and energy-dispersive X-ray (EDX) mapping. The electrochemical investigations of the oxyhalides catalysts showed that the doping of F, Cl, or Br into the Sr<sub>2</sub>CoO<sub>4</sub> parent oxide enhances the electrocatalytic activity for the oxygen evolution reaction (OER) with the onset potential as well as the potential required to achieve a current density of 10 mA/cm<sup>2</sup> shifting to lower potential values in the order of Sr<sub>2</sub>CoO<sub>4</sub> (1.64, 1.73) > Sr<sub>2</sub>CoO<sub>3</sub>Br (1.61, 1.65) > Sr<sub>2</sub>CoO<sub>3</sub>Cl (1.53, 1.60) > Sr<sub>2</sub>CoO<sub>3</sub>F (1.50, 1.56) V vs. HRE which indicates that Sr<sub>2</sub>CoO<sub>3</sub>F is the most active electrode among the studied catalysts under static and steady-state conditions. Moreover, Sr<sub>2</sub>CoO<sub>3</sub>F demonstrates long-term stability and remarkably less charge transfer resistance (R<sub>ct</sub> = 36.8 ohm) than the other oxyhalide counterparts during the OER. The doping of the perovskites with halide ions particularly the fluoride-ion enhances the surface oxygen vacancy density due to electron withdrawal away from the Co-atom which improves the ionic and electronic conductivity as well as the electrochemical activity of the oxygen evolution in alkaline solution.https://www.mdpi.com/2073-4344/11/11/1408strontium cobalt oxyhalideselectrocatalystoxygen evolution reactionalkaline solution |
| spellingShingle | Mohamed A. Ghanem Mabrook S. Amer Abdullah M. Al-Mayouf Prabhakarn Arunachalam Mark T. Weller Halide-Doping Effect of Strontium Cobalt Oxide Electrocatalyst and the Induced Activity for Oxygen Evolution in an Alkaline Solution Catalysts strontium cobalt oxyhalides electrocatalyst oxygen evolution reaction alkaline solution |
| title | Halide-Doping Effect of Strontium Cobalt Oxide Electrocatalyst and the Induced Activity for Oxygen Evolution in an Alkaline Solution |
| title_full | Halide-Doping Effect of Strontium Cobalt Oxide Electrocatalyst and the Induced Activity for Oxygen Evolution in an Alkaline Solution |
| title_fullStr | Halide-Doping Effect of Strontium Cobalt Oxide Electrocatalyst and the Induced Activity for Oxygen Evolution in an Alkaline Solution |
| title_full_unstemmed | Halide-Doping Effect of Strontium Cobalt Oxide Electrocatalyst and the Induced Activity for Oxygen Evolution in an Alkaline Solution |
| title_short | Halide-Doping Effect of Strontium Cobalt Oxide Electrocatalyst and the Induced Activity for Oxygen Evolution in an Alkaline Solution |
| title_sort | halide doping effect of strontium cobalt oxide electrocatalyst and the induced activity for oxygen evolution in an alkaline solution |
| topic | strontium cobalt oxyhalides electrocatalyst oxygen evolution reaction alkaline solution |
| url | https://www.mdpi.com/2073-4344/11/11/1408 |
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