Enhanced Photocatalytic Oxidative Coupling of Methane over Metal-Loaded TiO<sub>2</sub> Nanowires
The photocatalytic oxidative coupling of methane (OCM) on metal-loaded one-dimensional TiO<sub>2</sub> nanowires (TiO<sub>2</sub> NWs) was performed. With metal loading, the electric and optical properties of TiO<sub>2</sub> NWs were adjusted, contributing to the...
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
|
| Series: | Molecules |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1420-3049/30/2/206 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1832587844901666816 |
|---|---|
| author | Shuang Song Jiongcan Xiang Hui Kang Fengming Yang |
| author_facet | Shuang Song Jiongcan Xiang Hui Kang Fengming Yang |
| author_sort | Shuang Song |
| collection | DOAJ |
| description | The photocatalytic oxidative coupling of methane (OCM) on metal-loaded one-dimensional TiO<sub>2</sub> nanowires (TiO<sub>2</sub> NWs) was performed. With metal loading, the electric and optical properties of TiO<sub>2</sub> NWs were adjusted, contributing to the improvement of the activity and selectivity of the OCM reaction. In the photocatalytic OCM reaction, the 1.0 Au/TiO<sub>2</sub> NW catalyst exhibits an outstanding C<sub>2</sub>H<sub>6</sub> production rate (4901 μmol g<sup>−1</sup> h<sup>−1</sup>) and selectivity (70%), alongside the minor production of C<sub>3</sub>H<sub>8</sub> and C<sub>2</sub>H<sub>4</sub>, achieving a total C<sub>2</sub>–C<sub>3</sub> hydrocarbon selectivity of 75%. In contrast, catalysts loaded with Ag, Pd, and Pt show significantly lower activity, with Pt/TiO<sub>2</sub> NWs producing only CO<sub>2</sub>, indicating a propensity for the deep oxidation of methane. The O<sub>2</sub>-TPD analyses reveal that Au facilitates mild O<sub>2</sub> adsorption and activation, whereas Pt triggers excessive oxidation. Spectroscopic and kinetic studies demonstrate that Au loading not only enhances the separation efficiency of photogenerated electron–hole pairs, but also promotes the generation of active oxygen species in moderate amounts, which facilitates the formation of methyl radicals and their coupling into C<sub>2</sub>H<sub>6</sub> while suppressing over-oxidation to CO<sub>2</sub>. This work provides novel insights and design strategies for developing efficient photocatalysts. |
| format | Article |
| id | doaj-art-485b423b28a246dc98ea010b12755756 |
| institution | Kabale University |
| issn | 1420-3049 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj-art-485b423b28a246dc98ea010b127557562025-01-24T13:43:07ZengMDPI AGMolecules1420-30492025-01-0130220610.3390/molecules30020206Enhanced Photocatalytic Oxidative Coupling of Methane over Metal-Loaded TiO<sub>2</sub> NanowiresShuang Song0Jiongcan Xiang1Hui Kang2Fengming Yang3Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, ChinaInstitute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, ChinaInstitute of Advanced Study, Chengdu University, Chengdu 610106, ChinaCollege of Computer Science and Cyber Security (Pilot Software College), Chengdu University of Technology, Chengdu 610059, ChinaThe photocatalytic oxidative coupling of methane (OCM) on metal-loaded one-dimensional TiO<sub>2</sub> nanowires (TiO<sub>2</sub> NWs) was performed. With metal loading, the electric and optical properties of TiO<sub>2</sub> NWs were adjusted, contributing to the improvement of the activity and selectivity of the OCM reaction. In the photocatalytic OCM reaction, the 1.0 Au/TiO<sub>2</sub> NW catalyst exhibits an outstanding C<sub>2</sub>H<sub>6</sub> production rate (4901 μmol g<sup>−1</sup> h<sup>−1</sup>) and selectivity (70%), alongside the minor production of C<sub>3</sub>H<sub>8</sub> and C<sub>2</sub>H<sub>4</sub>, achieving a total C<sub>2</sub>–C<sub>3</sub> hydrocarbon selectivity of 75%. In contrast, catalysts loaded with Ag, Pd, and Pt show significantly lower activity, with Pt/TiO<sub>2</sub> NWs producing only CO<sub>2</sub>, indicating a propensity for the deep oxidation of methane. The O<sub>2</sub>-TPD analyses reveal that Au facilitates mild O<sub>2</sub> adsorption and activation, whereas Pt triggers excessive oxidation. Spectroscopic and kinetic studies demonstrate that Au loading not only enhances the separation efficiency of photogenerated electron–hole pairs, but also promotes the generation of active oxygen species in moderate amounts, which facilitates the formation of methyl radicals and their coupling into C<sub>2</sub>H<sub>6</sub> while suppressing over-oxidation to CO<sub>2</sub>. This work provides novel insights and design strategies for developing efficient photocatalysts.https://www.mdpi.com/1420-3049/30/2/206photocatalysisoxidative coupling of methaneTiO<sub>2</sub> nanowiresmild O<sub>2</sub> adsorption and activationactive oxygen species |
| spellingShingle | Shuang Song Jiongcan Xiang Hui Kang Fengming Yang Enhanced Photocatalytic Oxidative Coupling of Methane over Metal-Loaded TiO<sub>2</sub> Nanowires Molecules photocatalysis oxidative coupling of methane TiO<sub>2</sub> nanowires mild O<sub>2</sub> adsorption and activation active oxygen species |
| title | Enhanced Photocatalytic Oxidative Coupling of Methane over Metal-Loaded TiO<sub>2</sub> Nanowires |
| title_full | Enhanced Photocatalytic Oxidative Coupling of Methane over Metal-Loaded TiO<sub>2</sub> Nanowires |
| title_fullStr | Enhanced Photocatalytic Oxidative Coupling of Methane over Metal-Loaded TiO<sub>2</sub> Nanowires |
| title_full_unstemmed | Enhanced Photocatalytic Oxidative Coupling of Methane over Metal-Loaded TiO<sub>2</sub> Nanowires |
| title_short | Enhanced Photocatalytic Oxidative Coupling of Methane over Metal-Loaded TiO<sub>2</sub> Nanowires |
| title_sort | enhanced photocatalytic oxidative coupling of methane over metal loaded tio sub 2 sub nanowires |
| topic | photocatalysis oxidative coupling of methane TiO<sub>2</sub> nanowires mild O<sub>2</sub> adsorption and activation active oxygen species |
| url | https://www.mdpi.com/1420-3049/30/2/206 |
| work_keys_str_mv | AT shuangsong enhancedphotocatalyticoxidativecouplingofmethaneovermetalloadedtiosub2subnanowires AT jiongcanxiang enhancedphotocatalyticoxidativecouplingofmethaneovermetalloadedtiosub2subnanowires AT huikang enhancedphotocatalyticoxidativecouplingofmethaneovermetalloadedtiosub2subnanowires AT fengmingyang enhancedphotocatalyticoxidativecouplingofmethaneovermetalloadedtiosub2subnanowires |