1173018-52-4Relevant articles and documents
PHOTOINDUCED OXYGEN FORMATION AND SILVER-METAL DEPOSITION IN AQUEOUS SOLUTIONS OF VARIOUS SILVER SALTS BY SUSPENDED TITANIUM DIOXIDE POWDER
Nishimoto, Sei-Ichi,Ohtani, Bunsho,Kajiwara, Hiroshi,Kagiya, Tsutomu
, p. 2685 - 2694 (1983)
The photochemical reaction of Ar-purged aqueous solutions containing various silver salts and TiO2 powder in suspension has been studied at room temperature.Photoirradiation (λex was comparable to that of the anatase A)>.The molar ratio of deposited Ag metal to liberated O2, which was independent of the reaction rate, was equal to ca. 5 except for the case of TiO2(A)/AgClO4.The pH of the reaction mixture decreased with irradiation time, resulting in deactivation of the TiO2.Although O2 formation and Ag-metal deposition did not occur at pH 2, the photosensitizing activity of the TiO2 powder was recovered by the addition of NaOH.The addition of propan-2-ol to the deactivated acidic suspension of TiO2 was also effective for Ag-metal deposition but not for O2 formation.
Characterization and activity analysis of catalytic water oxidation induced by hybridization of [(OH2)(terpy)Mn(μ-O)2Mn(terpy) (OH2)]3+ and clay compounds
Narita, Komei,Kuwabara, Takayuki,Sone, Koji,Shimizu, Ken-Ichi,Yagi, Masayuki
, p. 23107 - 23114 (2006)
Hybridization of [(OH2)(terpy)Mn(μ-O)2Mn(terpy) (OH2)]3+ (terpy = 2,2′:6′,2″- terpyridine) (1) and mica clay yielded catalytic dioxygen (O2) evolution from water using a CeIV oxidant. The reaction was characterized by various spectroscopic measurements and a kinetic analysis of O2 evolution. X-ray diffraction (XRD) data indicates the interlayer separation of mica changes upon intercalation of 1. The UV-vis diffuse reflectance (RD) and Mn K-edge X-ray absorption near-edge structure (XANES) data suggest that the oxidation state of the di-μ-oxo Mn2 core is MnIII-MnIV, but it is not intact. In aqueous solution, the reaction of 1 with a large excess CeIV oxidant led to decomposition of 1 to form MnO4- ion without O2 evolution, most possibly by its disproportionation. However, MnO4- formation is suppressed by adsorption of 1 on clay. The maximum turnover number for O2 evolution catalyzed by 1 adsorbed on mica and kaolin was 15 and 17, respectively, under the optimum conditions. The catalysis occurs in the interlayer space of mica or on the surface of kaolin, whereas MnO 4- formation occurs in the liquid phase, involving local adsorption equilibria of adsorbed 1 at the interface between the clay surface and the liquid phase. The analysis of O2 evolution activity showed that the catalysis requires cooperation of two equivalents of 1 adsorbed on clay. The second-order rate constant based on the concentration (mol g -1) of 1 per unit weight of clay was 2.7 ± 0.1 mol -1 s-1 g for mica, which is appreciably lower than that for kaolin (23.9 ± 0.4 mol-1 s-1 g). This difference can be explained by the localized adsorption of 1 on the surface for kaolin. However, the apparent turnover frequency ((kO2) app/s-1) of 1 on mica was 2.2 times greater than on kaolin when the same fractional loading is compared. The higher cation exchange capacity (CEC) of mica statistically affords a shorter distance between the anionic sites to which 1 is attracted electrostatically, making the cooperative interaction between adsorbed molecules of 1 easier than that on kaolin. The higher CEC is important not only for attaining a higher loading but also for the higher catalytic activity of adsorbed 1.
An IrSi oxide film as a highly active water-oxidation catalyst in acidic media
Tran, Viet-Ha,Yatabe, Takeshi,Matsumoto, Takahiro,Nakai, Hidetaka,Suzuki, Kazuharu,Enomoto, Takao,Hibino, Takashi,Kaneko, Kenji,Ogo, Seiji
, p. 12589 - 12592 (2015)
We report an acid-stable Si oxide-doped Ir oxide film (IrSi oxide film), made by metal organic chemical vapour deposition (MOCVD) of an IrV complex for electrochemical water-oxidation. This is a successful improvement of catalytic ability and stability depending upon the pH of Ir oxide by doping of Si oxide. The turnover frequency (TOF) of the electrochemical water-oxidation by the IrSi oxide film is the highest of any Si oxide-doped Ir oxide materials and higher even than that of Ir oxide in acidic media.
Efficient photocatalytic water oxidation catalyzed by polyoxometalate [Fe11(H2O)14(OH)2(W3O10)2(α-SbW9O33)6]27- based on abundant metals
Du, Xiaoqiang,Ding, Yong,Song, Fangyuan,Ma, Baochun,Zhao, Junwei,Song, Jie
, p. 13925 - 13928 (2015/09/07)
An eleven iron-containing nanoscale inorganic polyanionic oxide cluster was reported as the first example for exceptional photocatalytic water oxidation. Under optimal conditions, a remarkable turn-over number (TON) of 1815 ± 50 and a turn-over frequency (TOFinitial) of 6.3 s-1 over 1 were achieved for water oxidation.
