| AVS 63rd International Symposium & Exhibition | |
| Surface Science | Tuesday Sessions |
| Session SS-TuP |
| Session: | Surface Science Poster Session |
| Presenter: | Isao Nakamura, National Institute of Advanced Industrial Science and Technology (AIST), Japan |
| Authors: | I. Nakamura, National Institute of Advanced Industrial Science and Technology (AIST), Japan M. Tokunaga, Kyushu University, Japan T. Fujitani, National Institute of Advanced Industrial Science and Technology (AIST), Japan |
| Correspondent: | Click to Email |
It is known that dimethyl trisulfide (DMTS) is mainly responsible for an off-flavor that develops during the storage of Japanese sake. Recently, we found that the supported gold catalysts are effective for the adsorption and removal of DMTS. In this study, in order to clarify the reaction properties of DMTS over gold, we investigated the adsorption and decomposition of DMTS using the Au(111) single-crystal surface.
First, we examined the influence of the exposure temperature on the adsorption properties of DMTS. X-ray photoelectron spectroscopy (XPS) results indicated that DMTS is dissociatively adsorbed as CH3S and CH3SS species at 100–300 K. Furthermore, both the dissociative adsorption rate and the saturation coverage were the same regardless of the exposure temperature.
In contrast, the thermal decomposition properties of CH3S and CH3SS strongly depended on their formation temperatures. On the Au(111) surface formed at 100 K, the CH3S was shown to be associatively desorbed as dimethyl disulfide (DMDS), and the production of ethane and atomic sulfur by the cleavage of C–S bond in CH3SS were confirmed from temperature-programmed desorption and XPS measurements. Thus, CH3S and CH3SS reacted individually. On the other hand, the reaction of CH3S with CH3SS to produce DMDS and atomic sulfur was also confirmed for the surface at 150 K. At 200 K or 300 K, only the reaction of CH3S with CH3SS was observed. We consider that the difference in the decomposition reaction is due to that the adsorption structure of CH3S and CH3SS species on Au(111) changes by their formation temperatures. That is, the CH3S and CH3SS species are present in separate islands each other at 100 K, whereas the adsorption structure of CH3S and CH3SS becomes random with rising their formation temperatures.