Visible light induced hole transport from sensitizer to Co3O4 water oxidation catalyst across nanoscale silica barrier with embedded molecular wires
In an artificial photosynthetic system, separation of the catalytic sites for water oxidation from those of carbon dioxide reduction by a gas impermeable physical barrier is an important requirement for avoiding cross and back reactions. Here, an approach is explored that uses crystalline Co3O4 as a...
| Main Authors: | , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
2013
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| Online Access: | https://hdl.handle.net/10356/103142 http://hdl.handle.net/10220/16947 |
| _version_ | 1826111161273155584 |
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| author | Agiral, Anil Soo, Han Sen Frei, Heinz |
| author2 | School of Physical and Mathematical Sciences |
| author_facet | School of Physical and Mathematical Sciences Agiral, Anil Soo, Han Sen Frei, Heinz |
| author_sort | Agiral, Anil |
| collection | NTU |
| description | In an artificial photosynthetic system, separation of the catalytic sites for water oxidation from those of carbon dioxide reduction by a gas impermeable physical barrier is an important requirement for avoiding cross and back reactions. Here, an approach is explored that uses crystalline Co3O4 as an oxygen evolving catalyst and a nanometer-thin dense phase silica layer as the separation barrier. For controlled charge transport across the barrier, hole conducting molecular wires are embedded in the silica. Spherical Co3O4(4 nm)–SiO2(2 nm) core–shell nanoparticles with p-oligo(phenylenevinylene) wire molecules (three aryl units, PV3) cast into the silica were developed to establish proof of concept for charge transport across the embedded wire molecules. FT-Raman, FT-infrared, and UV–visible spectroscopy confirmed the integrity of the organic wires upon casting in silica. Transient optical absorption spectroscopy of a visible light sensitizer (ester derivatized [Ru(bpy)3]2+ complex) indicates efficient charge injection into Co3O4–SiO2 particles with embedded wire molecules in aqueous solution. An upper limit of a few microseconds is inferred for the residence time of the hole on the embedded PV3 molecule before transfer to Co3O4 takes place. The result was corroborated by light on/off experiments using rapid-scan FT-IR monitoring. These observations indicate that hole conducting organic wire molecules cast into a dense phase, nanometer thin silica layer offer fast, controlled charge transfer through a product-separating oxide barrier. |
| first_indexed | 2024-10-01T02:46:28Z |
| format | Journal Article |
| id | ntu-10356/103142 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T02:46:28Z |
| publishDate | 2013 |
| record_format | dspace |
| spelling | ntu-10356/1031422020-03-07T12:34:53Z Visible light induced hole transport from sensitizer to Co3O4 water oxidation catalyst across nanoscale silica barrier with embedded molecular wires Agiral, Anil Soo, Han Sen Frei, Heinz School of Physical and Mathematical Sciences In an artificial photosynthetic system, separation of the catalytic sites for water oxidation from those of carbon dioxide reduction by a gas impermeable physical barrier is an important requirement for avoiding cross and back reactions. Here, an approach is explored that uses crystalline Co3O4 as an oxygen evolving catalyst and a nanometer-thin dense phase silica layer as the separation barrier. For controlled charge transport across the barrier, hole conducting molecular wires are embedded in the silica. Spherical Co3O4(4 nm)–SiO2(2 nm) core–shell nanoparticles with p-oligo(phenylenevinylene) wire molecules (three aryl units, PV3) cast into the silica were developed to establish proof of concept for charge transport across the embedded wire molecules. FT-Raman, FT-infrared, and UV–visible spectroscopy confirmed the integrity of the organic wires upon casting in silica. Transient optical absorption spectroscopy of a visible light sensitizer (ester derivatized [Ru(bpy)3]2+ complex) indicates efficient charge injection into Co3O4–SiO2 particles with embedded wire molecules in aqueous solution. An upper limit of a few microseconds is inferred for the residence time of the hole on the embedded PV3 molecule before transfer to Co3O4 takes place. The result was corroborated by light on/off experiments using rapid-scan FT-IR monitoring. These observations indicate that hole conducting organic wire molecules cast into a dense phase, nanometer thin silica layer offer fast, controlled charge transfer through a product-separating oxide barrier. 2013-10-28T02:58:14Z 2019-12-06T21:06:26Z 2013-10-28T02:58:14Z 2019-12-06T21:06:26Z 2013 2013 Journal Article Agiral, A., Soo, H. S.,& Frei, H. (2013). Visible Light Induced Hole Transport from Sensitizer to Co3O4 Water Oxidation Catalyst across Nanoscale Silica Barrier with Embedded Molecular Wires. Chemistry of Materials, 25(11), 2264-2273. https://hdl.handle.net/10356/103142 http://hdl.handle.net/10220/16947 10.1021/cm400759f en Chemistry of materials |
| spellingShingle | Agiral, Anil Soo, Han Sen Frei, Heinz Visible light induced hole transport from sensitizer to Co3O4 water oxidation catalyst across nanoscale silica barrier with embedded molecular wires |
| title | Visible light induced hole transport from sensitizer to Co3O4 water oxidation catalyst across nanoscale silica barrier with embedded molecular wires |
| title_full | Visible light induced hole transport from sensitizer to Co3O4 water oxidation catalyst across nanoscale silica barrier with embedded molecular wires |
| title_fullStr | Visible light induced hole transport from sensitizer to Co3O4 water oxidation catalyst across nanoscale silica barrier with embedded molecular wires |
| title_full_unstemmed | Visible light induced hole transport from sensitizer to Co3O4 water oxidation catalyst across nanoscale silica barrier with embedded molecular wires |
| title_short | Visible light induced hole transport from sensitizer to Co3O4 water oxidation catalyst across nanoscale silica barrier with embedded molecular wires |
| title_sort | visible light induced hole transport from sensitizer to co3o4 water oxidation catalyst across nanoscale silica barrier with embedded molecular wires |
| url | https://hdl.handle.net/10356/103142 http://hdl.handle.net/10220/16947 |
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