論文 - 鳥本　司

Photoelectrochemical Properties of Size-Quantized CdS Microcrystals Modified with Various Amounts of Viologen-Functionalized Thiol 査読有り

T. Torimoto, K. Maeda, J. Maenaka, and H. Yoneyama

J. Phys. Chem.   98 巻 ( 51 ) 頁： 13658-13664   1994年

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Size-quantized CdS microcrystals (Q-CdS) modified with various amounts of electroactive 1-decyl-1'-(3-mercaptopropyl)-4,4'-bipyridinium dibromide (VSH) and electroinactive decanethiol were prepared. The surface-modified VSH was photoreduced by irradiation of Q-CdS to give both dimeric and monomeric radical cations of the viologen, and the formation of the former was enhanced by increasing the amount of the surface-bound VSH. Kinetic analyses revealed that the rate constants for the reduction of the surface-modified VSH and for the reoxidation of the produced radical cations were independent of the amount of the VSH, Q-CdS having the higher amount of VSH showed the higher activity for electron transfer to methylene blue in solution, evidencing that the surface-bound viologen mediated electron transfers from Q-CdS to the electron acceptor in solution.

DOI： 10.1021/j100102a036

Effect of Surface Charge of 4-Aminothiophenol-Modified PbS Microcrystal Photocatalysts on Photoinduced Charge Transfer 査読有り

T. Torimoto, T. Sakata, H. Mori, and H. Yoneyama

J.Phys.Chem.   98 巻 ( 11 ) 頁： 3036-3043   1994年

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Two kinds of quantized PbS microcrystals modified with 4-aminothiophenol (4-ATP/Q-PbS) having different surface coverage were prepared by using two different concentration ratios of [Pb2+]/[S2-] in the synthesis of the 4-ATP/Q-PbS particles. The rates of photoinduced reduction of methylviologen on the two kinds of 4-ATP/Q-PbS particles were influenced by the kind of hole scavengers (sodium tartrate or triethanolamine) and the pH of solutions, and the higher reduction rates were obtained under conditions where the higher amount of adsorption of the hole scavenger occurred. High reduction rates of methylviologen were obtained at the photocatalyst having a high coverage of the surface modifier, because high electrostatic attractive interactions between the hole scavenger and the surface are operative when tartrate was used as a hole scavenger and a high amount of adsorption sites due to a high coverage of the surface modifier are available when triethanolamine was used. The validity of such interpretation was supported by kinetic analysis based on rate equations. Furthermore, it was found that inert electrolyte anions such as ClO4- had a retarding action for the photoreduction of methylviologen when tartrate was used as the hole scavenger, as a result that the adsorbed tartrate anions were replaced by the inert electrolyte anions depending on their concentrations. The adsorbability of inert electrolyte anions (Cl-, Br-, and ClO4-) as well as tartrate anions was found to be influenced by the degree of surface modification of the Q-PbS particles with 4-aminothiophenol. As for the case of using electronically neutral triethanolamine as the hole scavenger, the inert electrolyte anions did not influence the photoreduction rate of methylviologen.

Surface Structures of PbS Microcrystals Modified with 4-Hydroxythiophenol and Their Influences on Photoinduced Charge Transfer 査読有り

T. Torimoto, H. Uchida, T. Sakata, H. Mori, and H. Yoneyama

J. Am. Chem. Soc.,   115 巻 ( 5 ) 頁： 1874-1880   1993年

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Quantized PbS microcrystals capped with 4-hydroxythiophenol (ArSH) were prepared using two different concentration ratios of [Pb2+]/[S2-] = 1.2 and 3.0 with fixed concentration ratio of [ArSH]/[Pb2+] = 4.0. The size distributions of the prepared PbS particles were determined. Two different surface structure models of fully occupied and partially occupied surface sites of PbS microcrystals with the capped ArSH are assumed, and chemical compositions of these particles are evaluated by taking the experimentally determined particle size distributions into account. By examining the fitness of the chemical analyses data of the PbS particles to the evaluated compositions, it is proposed that the PbS particles prepared [Pb2+]/[S2-] = 3.0 had the capped ArSH in all the surface sites, while PbS particles prepared with [Pb2+]/[S2-] = 1.2 had some surface sites free from the modifier. The proposed surface structures of the two kinds of PbS microcrystals were rationalized by experimentally found differences both in agglomeration tendencies of the particles and in the effect of the addition of Pb2+ ions on the rate of photoinduced reduction of methyl viologen on the particles.

Effects of Size Quantization of Zinc Sulfide Microcrystallites on Photocatalytic Reduction of Carbon Dioxide 査読有り

H. Inoue, T. Torimoto, T. Sakata, H. Mori, and H. Yoneyama

Chem. Lett.   ( 9 ) 頁： 1483-1486   1990年

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）