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Saeki, Morihisa*; Matsumura, Daiju; Nakanishi, Ryuzo*; Yomogida, Takumi; Tsuji, Takuya; Saito, Hiroyuki*; Oba, Hironori*
Journal of Physical Chemistry C, 126(12), p.5607 - 5616, 2022/03
Times Cited Count:2 Percentile:14.72(Chemistry, Physical)The reaction mechanism of the direct photoreduction of a Rh ion complex to a Rh
species induced by pulsed ultraviolet laser irradiation was studied using dispersive X-ray absorption fine structure (DXAFS) spectroscopy. The time-resolved X-ray absorption near edge structure (XANES) showed the absence of isosbestic points and suggested that more than two Rh
species contribute toward the direct photoreduction of Rh
. Analysis of the time-resolved XANES data by singular value deposition showed that the direct photoreduction involves three Rh
species. Multivariate curve resolution by alternating least-squares analysis (MCR-ALS) of the time-resolved XANES data gave pure spectra and concentration profiles of the three Rh
species. The Rh
species were assigned to Rh
, Rh
, and Rh
species based on the features of the pure XANES spectra. The concentration profiles suggested that the direct photoreduction proceeds in the order of Rh
Rh
Rh
. A reaction mechanism, which was proposed involving photoreductions of Rh
and Rh
, photoinduced autocatalytic reductions of Rh
and Rh
, and photooxidation of Rh
, well reproduced the concentration profiles of three Rh
species.
Yaita, Tsuyoshi; Ikeda, Takashi; Matsumura, Daiju
Nihon Genshiryoku Gakkai-Shi ATOMO, 56(6), p.366 - 371, 2014/06
no abstracts in English
Saeki, Morihisa*; Matsumura, Daiju; Nakanishi, Ryuzo*; Yomogida, Takumi; Tsuji, Takuya; Saito, Hiroyuki*; Oba, Hironori*
no journal, ,
The precious metal (PM) ions complexed with negative ions and water molecules in solution has a charge transfer absorption band in the UV region. When alcohol is added to such a PM complex solution and irradiated with an ultraviolet laser, the PM
complex is electronically excited and reacts with the alcohol to be reduced to the neutral atom PM
. The reduced PM
spontaneously aggregates in the solution to form fine particles. This process is called Laser-Induced Particle Formation (LIPF), and is used for the formation of precious metal nanoparticles and the recovery of precious metals from factory effluents. We have investigated the LIPF reaction mechanism of Rh
ion complexes by in situ energy-dispersive X-ray absorption fine structure spectroscopy(XAFS). As a result of analyzing the obtained XAFS spectra, we found that Rh species with three oxidation numbers are involved in the Rh
reduction reaction, which proceeds from Rh
to Rh
(intermediate) to Rh
.
Saeki, Morihisa*; Matsumura, Daiju; Nakanishi, Ryuzo*; Yomogida, Takumi; Tsuji, Takuya; Saito, Hiroyuki*; Oba, Hironori*
no journal, ,
The reaction mechanism of the direct photo-reduction of a Rh ion complex to a Rh
species was studied using dispersive X-ray absorption fine structure spectroscopy. The time-resolved X-ray absorption near edge structure (XANES) showed the absence of isosbestic points. It suggested that more than two Rhn+ species contribute toward the reaction. We applied singular value deposition to the time-resolved XANES data and showed the contribution of three Rh
species to the direct photoreduction. Next, in order to extract spectral information on the Rh
intermediate, we analyzed the time-resolved XANES data using multivariate curve resolution analysis, which gives pure spectra and concentration profile of the Rh
species. Finally, based on feature of the pure spectrum, we assigned the Rh
intermediate to the Rh
species.