Synthesis of Cobalt Oxide on FTO by Hydrothermal Method for Photoelectrochemical Water Splitting Application
Cobalt oxide thin films were successfully grown directly on fluorine-doped tin oxide glass substrates through a simple, green, and low-cost hydrothermal method. An investigation into the physicochemical characteristics and photoelectrochemical (PEC) properties of the developed cobalt oxide thin film...
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MDPI AG
2021-03-01
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| author | Siti Nurul Falaein Moridon Mohd Nur Ikhmal Salehmin Khuzaimah Arifin Lorna Jeffery Minggu Mohammad B. Kassim |
| author_facet | Siti Nurul Falaein Moridon Mohd Nur Ikhmal Salehmin Khuzaimah Arifin Lorna Jeffery Minggu Mohammad B. Kassim |
| author_sort | Siti Nurul Falaein Moridon |
| collection | DOAJ |
| description | Cobalt oxide thin films were successfully grown directly on fluorine-doped tin oxide glass substrates through a simple, green, and low-cost hydrothermal method. An investigation into the physicochemical characteristics and photoelectrochemical (PEC) properties of the developed cobalt oxide thin film was comprehensively performed. At various annealing temperatures, different morphologies and crystal phases of cobalt oxide were observed. Microflowers (Co<sub>3</sub>O<sub>4</sub>) and microflowers with nanowire petals (Co<sub>3</sub>O<sub>4</sub>/CoO) were produced at 450 °C and 550 °C, respectively. Evaluation of the PEC performance of the samples in KOH (pH 13), Na<sub>2</sub>SO<sub>4</sub> (pH 6.7), and H<sub>2</sub>SO<sub>4</sub> (pH 1) revealed that the highest photocurrent −2.3 mA cm<sup>−2</sup> generated at −0.5 V vs. reversible hydrogen electrode (RHE) was produced by Co<sub>3</sub>O<sub>4</sub> (450 °C) in H<sub>2</sub>SO<sub>4</sub> (pH 1). This photocurrent corresponded to an 8-fold enhancement compared with that achieved in neutral and basic electrolytes and was higher than the results reported by other studies. This promising photocurrent generation was due to the abundant source of protons, which was favorable for the hydrogen evolution reaction (HER) in H<sub>2</sub>SO<sub>4</sub> (pH 1). The present study showed that Co<sub>3</sub>O<sub>4</sub> is photoactive under acidic conditions, which is encouraging for HER compared with the mixed-phase Co<sub>3</sub>O<sub>4</sub>/CoO. |
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| language | English |
| last_indexed | 2024-03-10T12:49:11Z |
| publishDate | 2021-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-3a11d5c9fa5046ab80d838bbcd1d46a72023-11-21T13:12:34ZengMDPI AGApplied Sciences2076-34172021-03-01117303110.3390/app11073031Synthesis of Cobalt Oxide on FTO by Hydrothermal Method for Photoelectrochemical Water Splitting ApplicationSiti Nurul Falaein Moridon0Mohd Nur Ikhmal Salehmin1Khuzaimah Arifin2Lorna Jeffery Minggu3Mohammad B. Kassim4Fuel Cell Institute, Universiti Kebangsaan Malaysia, Bangi 43600, MalaysiaFuel Cell Institute, Universiti Kebangsaan Malaysia, Bangi 43600, MalaysiaFuel Cell Institute, Universiti Kebangsaan Malaysia, Bangi 43600, MalaysiaFuel Cell Institute, Universiti Kebangsaan Malaysia, Bangi 43600, MalaysiaFuel Cell Institute, Universiti Kebangsaan Malaysia, Bangi 43600, MalaysiaCobalt oxide thin films were successfully grown directly on fluorine-doped tin oxide glass substrates through a simple, green, and low-cost hydrothermal method. An investigation into the physicochemical characteristics and photoelectrochemical (PEC) properties of the developed cobalt oxide thin film was comprehensively performed. At various annealing temperatures, different morphologies and crystal phases of cobalt oxide were observed. Microflowers (Co<sub>3</sub>O<sub>4</sub>) and microflowers with nanowire petals (Co<sub>3</sub>O<sub>4</sub>/CoO) were produced at 450 °C and 550 °C, respectively. Evaluation of the PEC performance of the samples in KOH (pH 13), Na<sub>2</sub>SO<sub>4</sub> (pH 6.7), and H<sub>2</sub>SO<sub>4</sub> (pH 1) revealed that the highest photocurrent −2.3 mA cm<sup>−2</sup> generated at −0.5 V vs. reversible hydrogen electrode (RHE) was produced by Co<sub>3</sub>O<sub>4</sub> (450 °C) in H<sub>2</sub>SO<sub>4</sub> (pH 1). This photocurrent corresponded to an 8-fold enhancement compared with that achieved in neutral and basic electrolytes and was higher than the results reported by other studies. This promising photocurrent generation was due to the abundant source of protons, which was favorable for the hydrogen evolution reaction (HER) in H<sub>2</sub>SO<sub>4</sub> (pH 1). The present study showed that Co<sub>3</sub>O<sub>4</sub> is photoactive under acidic conditions, which is encouraging for HER compared with the mixed-phase Co<sub>3</sub>O<sub>4</sub>/CoO.https://www.mdpi.com/2076-3417/11/7/3031cobalt oxidemixed-phasephotoelectrochemicalwater splitting |
| spellingShingle | Siti Nurul Falaein Moridon Mohd Nur Ikhmal Salehmin Khuzaimah Arifin Lorna Jeffery Minggu Mohammad B. Kassim Synthesis of Cobalt Oxide on FTO by Hydrothermal Method for Photoelectrochemical Water Splitting Application Applied Sciences cobalt oxide mixed-phase photoelectrochemical water splitting |
| title | Synthesis of Cobalt Oxide on FTO by Hydrothermal Method for Photoelectrochemical Water Splitting Application |
| title_full | Synthesis of Cobalt Oxide on FTO by Hydrothermal Method for Photoelectrochemical Water Splitting Application |
| title_fullStr | Synthesis of Cobalt Oxide on FTO by Hydrothermal Method for Photoelectrochemical Water Splitting Application |
| title_full_unstemmed | Synthesis of Cobalt Oxide on FTO by Hydrothermal Method for Photoelectrochemical Water Splitting Application |
| title_short | Synthesis of Cobalt Oxide on FTO by Hydrothermal Method for Photoelectrochemical Water Splitting Application |
| title_sort | synthesis of cobalt oxide on fto by hydrothermal method for photoelectrochemical water splitting application |
| topic | cobalt oxide mixed-phase photoelectrochemical water splitting |
| url | https://www.mdpi.com/2076-3417/11/7/3031 |
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