| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2016) | |
| Nanomaterials | Wednesday Sessions |
| Session NM-WeP |
| Session: | Nanomaterials Poster Session |
| Presenter: | Hideto Furuno, Nagaoka University of Technology, Japan |
| Authors: | H. Furuno, Nagaoka University of Technology, Japan N. Saito, Nagaoka University of Technology, Japan K. Sato, Nagaoka University of Technology, Japan M. Nishikawa, Nagaoka University of Technology, Japan |
| Correspondent: | Click to Email |
1. Introduction
In recent years, the issue of global warming caused by a greenhouse effect gas such as CO2 has been becoming deeply. Fossil fuels are exhaustible resource, and CO2 is released into the atmosphere by their combustion. In order to solve these problems, artificial photosynthesis using photocatalyst is one of promising approach. We have been studied photocatalytic overall water splitting into H2 and O2 on CeO2, and showed that proper metal-ion-doped CeO2 has a sufficient ability to split water by UV irradiation.[1] Although hydrogen is expected as the clean energy source, some problems such as storage and transport remains to be solved. On the other hand, CH4 has attracted much interest as useful fuel because of their conventional chemical properties. In this study, we payed attention to convert CO2 to CH4 by artificial photosynthesis on Pt-loaded Sm-doped CeO2 photocatalyst.
2. Experimental
Sm-doped CeO2 was prepared by heating of Sm2O3 and CeO2 mixtures at 1373 K for 16 h in air. Pt was deposited on the as-prepared Sm-doped CeO2 surface by photodeposition method as a co-catalyst. Prepared Pt-loaded Sm-doped CeO2 was characterized by X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). Photocatalytic CO2 reduction was carried out by a hand-made closed gas circulation apparatus directly connected to a gas-chromatograph equipped with BID detector. Photocatalyst was dispersed in distilled water and irradiated by a UV-lamp. CO2 gas was filled with vessel before light irradiation.
3. Results and discussion
In XRD measurements, the as-prepared Sm-doped CeO2 showed well-defined fluorite crystal structure with significant peak shift corresponding to Sm doping into their lattice. SEM images indicated that Pt was highly dispersed on CeO2 surface after photodeposition. As products for photocatalytic reaction, CH4 and H2 were detected without producing CO. It is interesting that CO that is a major product for CO2 reduction was not detected. It is well known fact that Pt has an ability to adsorb CO strongly. These results indicate that Pt-loading plays an important role for CO adsorption and lead to selective CH4 production for photocatalytic CO2 reduction.
4. Conclusions
Photocatalytic CO2 reduction on Pt-loaded Sm-doped CeO2 was investigated. Pt-loaded Sm-doped CeO2 showed selective CH4 production. This results indicate that metal-ion-doped CeO2 become a suitable material for photocatalytic CO2 reduction, and the combination between metal-ion-doped CeO2 and co-catalyst will be an important factor for selective CH4 production.
References
[1] H. Kadowaki, N. Saito, H. Nishiyama, Y. Inoue, Chem. Lett. 36, 440-441 (2007).