17410-58-1Relevant articles and documents
Role of Lattice Oxygen in the Oxygen Evolution Reaction on Co3O4: Isotope Exchange Determined Using a Small-Volume Differential Electrochemical Mass Spectrometry Cell Design
Amin, Hatem M. A.,K?nigshoven, Peter,Hegemann, Martina,Baltruschat, Helmut
, p. 12653 - 12660 (2019)
This work demonstrates the role of lattice oxygen of metal oxide catalysts in the oxygen evolution reaction (OER) as evidenced by isotope labeling together with the differential electrochemical mass spectrometry (DEMS) method. Our recent report assessed this role for Co3O4 using a flow-through DEMS cell, which requires a large volume of electrolyte. Herein, we extend this procedure to different Co3O4 catalyst loadings and particle sizes as well as the mixed Ag + Co3O4 catalyst. We introduce, for the first time, a novel small-volume DEMS cell design capable of using disc electrodes and only 3O4 catalyst is higher than that on the single Co3O4 catalyst, which illustrates the improved electrocatalytic activity previously reported on this mixed catalyst. Furthermore, the real surface area of the catalysts is estimated using different methods (namely, the ball model, double layer capacitance, isotope exchange, and redox peak methods). The surface areas estimated from the Brunauer-Emmett-Teller (BET) and ball models are comparable but roughly three times higher than that of the redox peak method. Our method represents an alternative approach for probing the mechanism and real surface area of catalysts.
Light-harvesting photocatalysis for water oxidation using mesoporous organosilica
Takeda, Hiroyuki,Ohashi, Masataka,Goto, Yasutomo,Ohsuna, Tetsu,Tani, Takao,Inagaki, Shinji
, p. 9130 - 9136 (2014)
An organic-based photocatalysis system for water oxidation, with visible-light harvesting antennae, was constructed using periodic mesoporous organosilica (PMO). PMO containing acridone groups in the framework (Acd-PMO), a visible-light harvesting antenna, was supported with [RuII(bpy) 32+] complex (bpy=2,2'-bipyridyl) coupled with iridium oxide (IrOx) particles in the mesochannels as photosensitizer and catalyst, respectively. Acd-PMO absorbed visible light and funneled the light energy into the Ru complex in the mesochannels through excitation energy transfer. The excited state of Ru complex is oxidatively quenched by a sacrificial oxidant (Na2S2O8) to form Ru 3+ species. The Ru3+ species extracts an electron from IrOx to oxidize water for oxygen production. The reaction quantum yield was 0.34 %, which was improved to 0.68 or 1.2 % by the modifications of PMO. A unique sequence of reactions mimicking natural photosystem II, 1) light-harvesting, 2) charge separation, and 3) oxygen generation, were realized for the first time by using the light-harvesting PMO. The lining's on the wall: A photocatalysis system for water oxidation linked with a solid light-harvesting antenna was constructed using periodic mesoporous organosilica (PMO), mimicking photosystem II. The acridone-containing PMO absorbed visible light and funneled the light energy into [Ru(bpy)3]2+ complex fixed in the mesochannels. Oxygen was evolved on IrOx nanoparticles deposited on the pore surface (see figure; bpy=2,2'-bipyridine).
Oxygen evolution from BF3/MnO4-
Yiu, Shek-Man,Man, Wai-Lun,Wang, Xin,Lam, William W. Y.,Ng, Siu-Mui,Kwong, Hoi-Ki,Lau, Kai-Chung,Lau, Tai-Chu
, p. 4159 - 4161 (2011)
MnO4- is activated by BF3 to undergo intramolecular coupling of two oxo ligands to generate O2. DFT calculations suggest that there should be a spin intercrossing between the singlet and triplet potential energy surfaces on going from the active intermediate [MnO2(OBF3)2]- to the O...O coupling transition state.
Kagóme Cobalt(II)-Organic Layers as Robust Scaffolds for Highly Efficient Photocatalytic Oxygen Evolution
Xu, Jiaheng,Wang, Zhi,Yu, Wenguang,Sun, Di,Zhang, Qing,Tung, Chen-Ho,Wang, Wenguang
, p. 1146 - 1152 (2016)
Two Kagóme cobalt(II)-organic layers of [Co3(μ3-OH)2(bdc)2]n (1) and [Co3(μ3-OH)2(chdc)2]n (2) (bdc=o-benzenedicarboxylate and chdc=1,2-cyclohexanedicarboxylate) that bear bridging OH- ligands were explored as water oxidation catalysts (WOCs) for photocatalytic O2 production. The activities of 1 and 2 towards H2O oxidation were assessed by monitoring the in situ O2 concentration versus time in the reaction medium by utilizing a Clark-type oxygen electrode under photochemical conditions. The oxygen evolution rate (RO2) was 24.3 μmol s-1 g-1 for 1 and 48.8 μmol s-1 g-1 for 2 at pH 8.0. Photocatalytic reaction studies show that 1 and 2 exhibit enhanced activities toward the oxidation of water compared to commercial nanosized Co3O4. In scaled-up photoreactions, the pH value of the reaction medium decreased from 8.0 to around 7.0 after 20 min and the O2 production ceased. Based on the amounts of the sacrificial oxidant (K2S2O8) used, the yield of O2 produced is 49.6 % for 2 and 29.8 % for 1. However, the catalyst can be recycled without a significant loss of catalytic activity. Spectroscopic studies suggest that the structure and composition of recycled 1 and 2 are maintained. In isotope-labeling H218O (97 % enriched) experiments, the distribution of 16O16O/16O18O/18O18O detected was 0:7.55:92.45, which is comparable to the theoretical values of 0.09:5.82:94.09. This work not only provides new catalysts that resemble ligand-protected cobalt oxide materials but also establishes the significance of the existence of OH- (or H2O) binding sites at the metal center in WOCs. Water splitting: Two assembled cobalt(II)-carboxylate layers that bear bridging OH- ligands are explored as water oxidation catalysts for photocatalytic O2 production. Their activities towards H2O oxidation are assessed by monitoring the in situ O2 concentration versus time in the reaction medium by utilizing a Clark-type oxygen electrode under photochemical conditions.
The Ru-Hbpp water oxidation catalyst
, p. 15176 - 15187 (2009)
A thorough characterization of the Ru-Hbpp (in,in-{[RuII(trpy) (H2O)]2(μ-bpp)}3+ (trpy is 2,2′:6′,2″-terpyridine, bpp is bis(2-pyridyl)-3,5-pyrazolate)) water oxidation catalyst has been carried out employing st
