17410-58-1

Upstream product

• 7732-18-5 water 
• 14797-71-8 ¹⁸O-labeled water 
• 14989-30-1 chlorine monoxide 
• 7758-19-2 sodium chlorite 
• 14380-61-1 hypochlorite 
• 7722-64-7 potassium permanganate 
• 80937-33-3 oxygen 

Downstream Products

• 42037-27-4 zirconium dihydroxide 
• 872207-78-8 Zr(OH)2(⁽¹⁸⁾OH)2 
• 756456-88-9 zirconium tetrahydroxide 
• 21908-53-2 HHgOH 
• 12135-13-6 mercury(II) hydroxide 
• 824975-61-3 HOHg⁽¹⁸⁾OH 
• 824975-60-2 Hg(⁽¹⁸⁾OH)2 

Relevant academic research and scientific papers

Role of Lattice Oxygen in the Oxygen Evolution Reaction on Co3O4: Isotope Exchange Determined Using a Small-Volume Differential Electrochemical Mass Spectrometry Cell Design

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.

Role of water oxidation in the photoreduction of graphene oxide

By means of a H218O labeling experiment in combination with mass spectrometry tracking, we studied GO photoreduction. Observation of 18O labeled O2 provides direct evidence to confirm that water oxidation occurs during GO photoreduction. In combination with DFT calculations, we propose a mechanism for O2 and CO2 evolution in the photoreduction of GO.

Light-harvesting photocatalysis for water oxidation using mesoporous organosilica

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).

Water oxidation catalysis with nonheme iron complexes under acidic and basic conditions: Homogeneous or heterogeneous?

Thermal water oxidation by cerium(IV) ammonium nitrate (CAN) was catalyzed by nonheme iron complexes, such as Fe(BQEN)(OTf)2 (1) and Fe(BQCN)(OTf)2 (2) (BQEN = N,N′-dimethyl-N,N′-bis(8- quinolyl)ethane-1,2-diamine, BQCN = N,N′-dimethyl-N,N′-bis(8- quinolyl)cyclohexanediamine, OTf = CF3SO3-) in a nonbuffered aqueous solution; turnover numbers of 80 ± 10 and 20 ± 5 were obtained in the O2 evolution reaction by 1 and 2, respectively. The ligand dissociation of the iron complexes was observed under acidic conditions, and the dissociated ligands were oxidized by CAN to yield CO2. We also observed that 1 was converted to an iron(IV)-oxo complex during the water oxidation in competition with the ligand oxidation. In addition, oxygen exchange between the iron(IV)-oxo complex and H 218O was found to occur at a much faster rate than the oxygen evolution. These results indicate that the iron complexes act as the true homogeneous catalyst for water oxidation by CAN at low pHs. In contrast, light-driven water oxidation using [Ru(bpy)3]2+ (bpy = 2,2′-bipyridine) as a photosensitizer and S2O8 2- as a sacrificial electron acceptor was catalyzed by iron hydroxide nanoparticles derived from the iron complexes under basic conditions as the result of the ligand dissociation. In a buffer solution (initial pH 9.0) formation of the iron hydroxide nanoparticles with a size of around 100 nm at the end of the reaction was monitored by dynamic light scattering (DLS) in situ and characterized by X-ray photoelectron spectra (XPS) and transmission electron microscope (TEM) measurements. We thus conclude that the water oxidation by CAN was catalyzed by short-lived homogeneous iron complexes under acidic conditions, whereas iron hydroxide nanoparticles derived from iron complexes act as a heterogeneous catalyst in the light-driven water oxidation reaction under basic conditions.

Oxygen evolution from BF3/MnO4-

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.

Water oxidation by a mononuclear ruthenium catalyst: Characterization of the intermediates

A detailed characterization of intermediates in water oxidation catalyzed by a mononuclear Ru polypyridyl complex [RuII-OH2] 2+ (Ru = Ru complex with one 4-t-butyl-2,6-di-(1′,8′- naphthyrid-2′-yl)-pyridine ligand and two 4-picoline ligands) has been carried out using electrochemistry, UV-vis and resonance Raman spectroscopy, pulse radiolysis, stopped flow, and electrospray ionization mass spectrometry (ESI-MS) with H218O labeling experiments and theoretical calculations. The results reveal a number of intriguing properties of intermediates such as [RuIV=O]2+ and [Ru IV-OO]2+. At pH > 2.9, two consecutive proton-coupled one-electron steps take place at the potential of the [RuIII-OH] 2+/[RuII-OH2]2+ couple, which is equal to or higher than the potential of the [RuIV=O] 2+/[RuIII-OH]2+ couple (i.e., the observation of a two-electron oxidation in cyclic voltammetry). At pH 1, the rate constant of the first one-electron oxidation by Ce(IV) is k1 = 2 × 104 M-1 s-1. While pH-independent oxidation of [RuIV=O]2+ takes place at 1420 mV vs NHE, bulk electrolysis of [RuII-OH2]2+ at 1260 mV vs NHE at pH 1 (0.1 M triflic acid) and 1150 mV at pH 6 (10 mM sodium phosphate) yielded a red colored solution with a Coulomb count corresponding to a net four-electron oxidation. ESI-MS with labeling experiments clearly indicates that this species has an O-O bond. This species required an additional oxidation to liberate an oxygen molecule, and without any additional oxidant it completely decomposed slowly to form [RuII-OOH]+ over 2 weeks. While there remains some conflicting evidence, we have assigned this species as 1[RuIV-·2-OO]2+ based on our electrochemical, spectroscopic, and theoretical observations alongside a previously reported analysis by T. J. Meyer group (J. Am. Chem. Soc. 2010, 132, 1545-1557).

Kagóme Cobalt(II)-Organic Layers as Robust Scaffolds for Highly Efficient Photocatalytic Oxygen Evolution

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.

Cobalt-Based Metal-Organic Cages for Visible-Light-Driven Water Oxidation

Water oxidation to molecular oxygen is indispensable but a challenge for splitting H2O. In this work, a series of Co-based metal-organic cages (MOCs) for photoinduced water oxidation were prepared. MOC-1 with both bis(μ-oxo) bridged dicobalt and Co-O (O from H2O) displays catalytic activity with an initial oxygen evolution rate of 80.4 mmol/g/h and a TOF of 7.49 × 10-3 s-1 in 10 min. In contrast, MOC-2 containing only Co-O (O from H2O) in the structure results in a lower oxygen evolution rate (40.8 mmol/g/h, 4.78 × 10-3 s-1), while the amount of oxygen evolved from the solution of MOC-4 without both active sites is undetectable. Isotope experiments with or without H218O as the reactant successfully demonstrate that the molecular oxygen was produced from water oxidation. Photophysical and electrochemical studies reveal that photoinduced water oxidation initializes via electron transfer from the excited [Ru(bpy)3]2+? to Na2S2O8, and then, the cobalt active sites further donate electrons to the oxidized [Ru(bpy)3]3+ to drive water oxidation. This proof-of-concept study indicates that MOCs can work as potential efficient catalysts for photoinduced water oxidation.

The Ru-Hbpp water oxidation catalyst

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

Concerted dismutation of chlorite ion: Water-soluble iron-porphyrins as first generation model complexes for chlorite dismutase

Three iron-5,10,15,20-tetraarylporphyrins (Fe(Por-Ar4), Ar = 2,3,5,6-tetrafluro-N, N, N-trimethylanilinium (1), N, N, N-trimethylanilinium (2), and p-sulfonatophenyl (3)) have been investigated as catalysts for the dismutation of chlorite (CIO