Spinel MnxCo3-xO4 (0 ≤ x ≤ 2.5) as oxygen reduction and evolution electrocatalysts in alkaline medium
Spinel oxides can serve as nonprecious metal-based bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which are the two fundamental reactions for energy conversion and storage device. In this report, highly efficient, bifunctional spinel oxide MnxC...
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Final Year Project (FYP) |
| Language: | English |
| Published: |
2015
|
| Subjects: | |
| Online Access: | http://hdl.handle.net/10356/62369 |
| _version_ | 1826117720847941632 |
|---|---|
| author | Xin, Ouyang |
| author2 | Xu Zhichuan Jason |
| author_facet | Xu Zhichuan Jason Xin, Ouyang |
| author_sort | Xin, Ouyang |
| collection | NTU |
| description | Spinel oxides can serve as nonprecious metal-based bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which are the two fundamental reactions for energy conversion and storage device. In this report, highly efficient, bifunctional spinel oxide MnxCo3-xO4 (x = 0.5, 0.75, 1, 1.5, 2, 2.5) was developed by solid state reaction under calcination temperature of 300 °C to 900 °C. X-ray diffraction (XRD) was used to investigate the crystal structure and Brunauer-Emmett-Teller (BET) method was used to obtain the active surface area. Cyclic voltammetry (CV) and rotating disk electrode (RDE) measurements were conducted to investigate the ORR and OER activity. It is observed that at calcination temperature of 900 °C, MnxCo3-xO4 with x ≤ 1 shows much better ORR specific activity compared to those with x > 1, which could be due to the difference of catalytic property between cubic spinel and tetragonal spinel phases. At 400 °C, ORR specific activity of cubic spinel MnxCo3-xO4 increases with increasing manganese substitution, which agrees with previous studies stating that Mn3+ / Mn4+ couple are the active sites for ORR. Whereas the trend of OER specific activity with varying manganese amount does not agree with the findings in previous studies. Best combination of ORR and OER specific activity is achieved in Mn1Co2O4. Comparing different calcination temperatures from 900 °C to 300 °C, it is observed that the ORR and OER specific activity of Mn1Co2O4 increase with increasing temperature. By plotting Koutecky-Levich plot, the electron transfer number of Mn1Co2O4 is obtained, implying 4e- pathway is the major mechanism. |
| first_indexed | 2024-10-01T04:31:55Z |
| format | Final Year Project (FYP) |
| id | ntu-10356/62369 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T04:31:55Z |
| publishDate | 2015 |
| record_format | dspace |
| spelling | ntu-10356/623692023-03-04T15:42:30Z Spinel MnxCo3-xO4 (0 ≤ x ≤ 2.5) as oxygen reduction and evolution electrocatalysts in alkaline medium Xin, Ouyang Xu Zhichuan Jason School of Materials Science and Engineering DRNTU::Engineering::Materials::Energy materials Spinel oxides can serve as nonprecious metal-based bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which are the two fundamental reactions for energy conversion and storage device. In this report, highly efficient, bifunctional spinel oxide MnxCo3-xO4 (x = 0.5, 0.75, 1, 1.5, 2, 2.5) was developed by solid state reaction under calcination temperature of 300 °C to 900 °C. X-ray diffraction (XRD) was used to investigate the crystal structure and Brunauer-Emmett-Teller (BET) method was used to obtain the active surface area. Cyclic voltammetry (CV) and rotating disk electrode (RDE) measurements were conducted to investigate the ORR and OER activity. It is observed that at calcination temperature of 900 °C, MnxCo3-xO4 with x ≤ 1 shows much better ORR specific activity compared to those with x > 1, which could be due to the difference of catalytic property between cubic spinel and tetragonal spinel phases. At 400 °C, ORR specific activity of cubic spinel MnxCo3-xO4 increases with increasing manganese substitution, which agrees with previous studies stating that Mn3+ / Mn4+ couple are the active sites for ORR. Whereas the trend of OER specific activity with varying manganese amount does not agree with the findings in previous studies. Best combination of ORR and OER specific activity is achieved in Mn1Co2O4. Comparing different calcination temperatures from 900 °C to 300 °C, it is observed that the ORR and OER specific activity of Mn1Co2O4 increase with increasing temperature. By plotting Koutecky-Levich plot, the electron transfer number of Mn1Co2O4 is obtained, implying 4e- pathway is the major mechanism. Bachelor of Engineering (Materials Engineering) 2015-03-24T02:07:24Z 2015-03-24T02:07:24Z 2015 2015 Final Year Project (FYP) http://hdl.handle.net/10356/62369 en Nanyang Technological University 50 p. application/pdf |
| spellingShingle | DRNTU::Engineering::Materials::Energy materials Xin, Ouyang Spinel MnxCo3-xO4 (0 ≤ x ≤ 2.5) as oxygen reduction and evolution electrocatalysts in alkaline medium |
| title | Spinel MnxCo3-xO4 (0 ≤ x ≤ 2.5) as oxygen reduction and evolution electrocatalysts in alkaline medium |
| title_full | Spinel MnxCo3-xO4 (0 ≤ x ≤ 2.5) as oxygen reduction and evolution electrocatalysts in alkaline medium |
| title_fullStr | Spinel MnxCo3-xO4 (0 ≤ x ≤ 2.5) as oxygen reduction and evolution electrocatalysts in alkaline medium |
| title_full_unstemmed | Spinel MnxCo3-xO4 (0 ≤ x ≤ 2.5) as oxygen reduction and evolution electrocatalysts in alkaline medium |
| title_short | Spinel MnxCo3-xO4 (0 ≤ x ≤ 2.5) as oxygen reduction and evolution electrocatalysts in alkaline medium |
| title_sort | spinel mnxco3 xo4 0 ≤ x ≤ 2 5 as oxygen reduction and evolution electrocatalysts in alkaline medium |
| topic | DRNTU::Engineering::Materials::Energy materials |
| url | http://hdl.handle.net/10356/62369 |
| work_keys_str_mv | AT xinouyang spinelmnxco3xo40x25asoxygenreductionandevolutionelectrocatalystsinalkalinemedium |