10028-15-6 Usage
Uses
1. Used in Water Treatment:
Ozone is used as a disinfectant for air and water by virtue of its oxidizing power. It is used to purify drinking water and to treat industrial wastes and sewage.
2. Used in Bleaching:
Ozone is used as a bleaching agent for textiles, oils, and waxes. It is also used in the manufacture of paper, steroid hormones, waxes, and cyanide.
3. Used in Organic Synthesis:
Ozone is used in organic syntheses and forms ozonides, which are sometimes useful oxidizing compounds.
4. Used in Air Treatment:
Ozone is used as an oxidizing compound and disinfectant for air, helping to deodorize and kill bacteria by passing dry air through special ozone-producing electronic devices.
5. Used in Rubber Industry:
Ozone is used as an oxidant in the rubber industry.
6. Agricultural Uses:
Ozone is used for killing germs, bleaching, removing unpleasant odors from food, and sterilizing water in the agricultural industry.
7. Environmental Protection:
Ozone in the upper layers of the atmosphere (stratosphere) is formed by the reaction of O2 with elemental oxygen formed from the splitting of O2 by UV radiation. The ozone layer in the stratosphere absorbs UV radiation and serves to protect Earth from the destructive and mutagenic properties of solar UV.
8. Health and Safety:
Ground-level ozone (troposphere) is formed largely from the reaction of the byproducts of the incomplete combustion of fossil fuels with elemental oxygen present. It can be very harmful to human health, and people with conditions such as emphysema, asthma, bronchitis, and heart conditions are especially susceptible. The US Environmental Protection Agency (EPA) has established exposure limits for ozone to protect public health.
Origin of Name
From the Greek words oxys (which means sharp or acid) and gen
(which means forming); together they stand for “acid-forming.” In the eighteenth century,
it was believed that all acids contained oxygen.
Characteristics
Ozone has a very distinctive pungent odor. It exists in our lower atmosphere in very smalltrace amounts. In higher concentrations it is irritating and even poisonous. Ozone is in relativelylow concentrations at sea level. In the upper atmosphere, where it is more concentrated,it absorbs ultraviolet radiation, which protects the Earth and us from excessive exposure toultraviolet radiation.Electrical discharges in the atmosphere produce small amounts of ozone. You can recognizethe odor when running electrical equipment that gives off sparks. Even toy electric trainscan produce ozone as they spark along the track. Ozone can be produced by passing dry airbetween two electrodes that are connected to alternating electric current with high voltage.Such a system is sometimes used to purify the air in buildings or provide ozone for commercialuses. Ozone is produced during the electrical discharges of lightning during storms. Thisis what makes the air seem so fresh after a thunderstorm or electrical storm. Besides beingproduced by electrical discharges, ozone is produced in the upper atmosphere or stratosphereby ultraviolet (UV) radiation from the sun strikingO2 molecules, breaking them down andreforming them as O3 molecules. The vast majority of ozone is produced in the atmosphereover the tropical latitudes because this area gets most of the radiation from more direct sunlight. Normal wind currents carry the ozone to the polar regions of the Earth where it isthickest.
History
It was once believed that air was a single element, but by the fifteenth century ce, scientistsbegan to question whether it was possibly at least two separate gases. Leonardo da Vinci wasone of the first to suggest the air consisted of at least two gases. He even determined that oneof them would support life and fire.In 1839 Christian Friedrich Schonbein (1799–1868) discovered a gas with an unusualodor coming from some electrical equipment. He did not know what it was, but because ithad an odd smell, he called it “ozone,” after the Greek word for “I smell.” Although he knewthat it was a chemical substance, he mistakenly associated ozone with the halogens (group 17).Others before Schonbein had smelled the gas but had not recognized its importance. ThomasAndrews (1813–1885) and several other scientists, through different experiments, identifiedozone as a form of oxygen (an allotrope). It was not until 1868 that J. Louis Soret establishedthe formula to be O3.
Production Methods
Ozone (triatomic oxygen) is a light blue gas with a characteristic
odor (reminiscent to some individuals of an electrical
discharge such as lightening). Ozone was first
described in 1840 by Christian Friedrich Schonbein
[1799–1868], who produced it from phosphorus and electrolysis
of water. Schonbein also developed a colorimetric assay
involving starch and potassiumiodide-impregnated paper that
was widely used to measure atmospheric ozone concentrations.
Interestingly, Schonbein’s studies were interrupted
when he discovered the acute toxicity of ozone in 1851 and
noted that ozone caused “a really painful affection of the chest,
a sort of asthma, connected with a violent cough”.
Concern of ozone’s toxicity dates back to the mid-twentieth century, when it was recognized as a major air pollutant in
urban areas. Additional concerns arose in the 1980s and 1990s
regarding its depletion in the stratosphere.
Ozone can be found naturally in the troposphere during
electrical storms and in the stratosphere. Background levels
of ozone in nonurban areas average about 10–20 ppb and are
due mainly to intrusion of stratospheric ozone into the lower
atmosphere.
Preparation
Ozone is generated from oxygen by passing an electric spark or silent electrical discharge through dry, and pure oxygen. This electrical discharge may be applied between two glass surfaces between which oxygen is passed. Many types of ozonizers (ozone generating apparatus) are known and commercially available for small-scale production of this gas for various uses. Ozone may be produced by electrolysis of chilled dilute sulfuric acid (e.g. 2.5N H2SO4) or perchloric acid at high current density (higher than that required to produce oxygen alone). A mixture of oxygen and ozone evolve at the anode.
Reactions
Ozone reacts (1) with potassium iodide, to liberate iodine, (2) with colored organic materials, e.g., litmus, indigo, to destroy the color, (3) with mercury, to form a thin skin of mercurous oxide causing the mercury to cling to the containing vessel, (4) with silver film, to form silver peroxide, Ag2O2, black, produced most readily at about 250 C, (5) with tetramethyldiaminodiphenylmethane (CH3)2N·C6H4·CH2·C6H4·N(CH3)2, in alcohol solution with a trace of acetic acid to form violet color (hydrogen peroxide, colorless; chlorine or bromine, blue; nitrogen tetroxide, yellow). In contrast to hydrogen peroxide, ozone does not react with dichromate, permanganate, or titanic salt solutions. Ozone reacts with olefin compounds to form ozonide addition compounds. Ozonides are readily split at the olefinin-ozone position upon warming alone, or upon warming their solutions in glacial acetic acid, with the formation of aldehyde and acid compounds which can be readily identified, thus serving to locate the olefin position in oleic acid, C17H33·COOH, as midway in the chain (CH3(CH2)7CH:CH(CH2)7COOH. Ozone is used (1) as a bleaching agent, e.g., for fatty oils, (2) as a disinfectant for air and H2O, (3) as an oxidizing agent.
Reactivity Profile
Ozone is a propellant; ignites upon contact with alcohols, amines, ammonia, beryllium alkyls, boranes, dicyanogen, hydrazines, hydrocarbons, hydrogen, nitroalkanes, powdered metals, silanes, or thiols [Bretherick 1979. p.174]. Aniline in a atmosphere of Ozone produces a white galatinous explosive ozobenzene [Mellor 1:911. 1946-47]. A mixture of ether and Ozone forms aldehyde and acetic acid and a heavy liquid, ethyl peroxide, an explosive [Mellor 1:911. 1946-47]. Severe explosions occur attempting to form tribromic octaoxide from bromine and Ozone [Mellor 2, Supp. 1:748. 1956]. Mixtures of Ozone and dinitrogen pentaoxide are flammable or explosive [Mellor 8, Supp. 2:276. 1967]. Ozone and ethylene react explosively [Berichte 38:3837]. Nitrogen dioxide and Ozone react with the evolution of light, and often explode [J. Chem. Phys. 18:366 1920]. Contact of very cold liquefied gas with water may result in vigorous or violent boiling of the product and extremely rapid vaporization due to the large temperature differences involved. If the water is hot, there is the possibility that a liquid "superheat" explosion may occur. Pressures may build to dangerous levels if liquid gas contacts water in a closed container, [Handling Chemicals Safely 1980].
Hazard
High concentrations of ozone are a fire and explosion hazard when in contact with anyorganic substance that can be oxidized.In moderately high concentrations ozone is very toxic when inhaled, and in lesser concentrations,it is irritating to the nose and eyes. Ozone in the lower atmosphere contributes to airpollution and smog. It can cause damage to rubber, plastics, and paints. These low concentrationscan cause headaches, burning eyes, and respiratory irritation. It is particular harmful toasthmatics and the elderly with respiratory problems.
Health Hazard
Ozone is a highly toxic gas that is extremely irritating to the eyes, mucous
membranes, and respiratory tract. The characteristic odor of ozone can be detected
below the permissible exposure limit, and this compound is therefore regarded to
have adequate warning properties. However, at higher concentrations the ability to
smell ozone may decrease. Inhalation of 1 ppm ozone may cause headaches and
irritation of the upper and lower respiratory tract. The first symptoms of exposure
include irritation of the eyes, dryness of throat, and coughing; these symptoms
disappear after exposure ceases. Exposure at higher levels may lead to lacrimation,
vomiting, upset stomach, labored breathing, lowering of pulse rate and blood
pressure, lung congestion, tightness in the chest, and pulmonary edema, which can
be fatal. Exposure to 100 ppm of ozone for 1 hour can be lethal to humans.
Animal studies indicate that chronic exposure to ozone may result in pulmonary
damage, leading to chronic lung impairment. Continual daily exposure to ozone can
cause premature aging.
Fire Hazard
Severe explosion hazard when shocked, exposed to heat or flame, or by chemical reaction with organic substances, especially reducing agents. Ozone is a powerful oxidizing agent. Incompatible with alkenes; aromatic compounds; benzene, rubber; bromine; dicyanogen; diethyl ether; dinitrogen tetroxide; hydrogen bromide; 4-hydroxy-4-methyl-1,6-heptadiene; nitrogen trichloride; stibine; tetrafluorohydrazine. Avoid contact with organic materials.
Flammability and Explosibility
Ozone by itself is not flammable. Liquid ozone and concentrated solutions are
extremely hazardous and can explode on warming or when shocked.
Safety Profile
A human poison by inhalation. Human systemic effects by inhalation: visual field changes, lachrymation, headache, decreased pulse rate with fall in blood pressure, dermatitis, cough, dyspnea, respiratory stimulation and other pulmonary changes. Experimental teratogenic and reproductive effects. Human mutation data reported. A skin, eye, upper respiratory system, and mucous membrane irritant. Questionable carcinogen with experimental neoplas tigenic and tumorigenic data. Can be a safe water dtsinfectant in low concentration. Concentration of 0.01 5 pprn of ozone in air produces a barely detectable odor. Concentrations of 1 ppm produce a dtsagreeable sulfur like odor and may cause headache and irritation of eyes and the upper respiratory tract; symptoms dtsappear after leaving the exposure. A powerful oxidning agent. Dangerous chemical reaction with acetylene, alkenes, alkylmetals (e.g., Imethylzinc, Iethylzinc), antimony, aromatic compounds (e.g., benzene, aniline), benzene + oxygen + rubber, bromine, charcoal + potassium iodide, citronelk acid, combustible gases (e.g., carbon monoxide, ethylene, nitrogen oxide, ammonia, phosphme), (dtallyl methyl carbinol + acetic acid), trans-2,3-dichloro-2butene, dicyanogen, dlenes + oxygen, dtethyl ether, 1,l -Ifluoroethylene, N205, ethylene + formyl fluoride, fluoroethylene, liquid hydrogen, hydrogen + oxygen difluoride, hydrogen bromide, hydrogen iodide, 4-hydroxy-4-methyl-1 ,6-heptadtene, 2,3-hydroxy-2,2,4-trimethyl-3-pentenoic acid lactone, isopropylidene compounds, nitrogen, NOZ, NOx nitrogen trichloride, nitrogen triiodide, nitroglycerin, organic liquids, organic matter, oxygen + rubber powder, oxygen fluorides (e.g., dioxygen difluoride, dioxygen trifluoride), shca gel, stibine, tetrafluorohydrazine, tetramethylammonium hydroxide, trifluoroethylene, unsaturated acetals. A severe explosion hazard in liquid form when shocked, exposed to heat or flame, or in concentrated form by chemical reaction with powerful reducing agents. Incompatible with rubber; dinltrogen tetraoxide. See also OZONIDES and PEROXIDES.
Potential Exposure
Ozone is found naturally in the
atmosphere as a result of the action of solar radiation and
electrical storms. It is also formed around electrical
sources, such as X-ray or ultraviolet generators, electric
arcs; mercury vapor lamps; linear accelerators; and electrical discharges. Ozone is used as an oxidizing agent
in the organic chemical industry (e.g., production of azelaic
acid); as a disinfectant for air, mold and bacteria
inhibitor for food in cold storage rooms, and for water
(e.g., public water supplies; swimming pools; and sewage
treatment); for bleaching textiles; waxes, flour, mineral
oils, and their derivatives; paper pulp; starch, and sugar;
for aging liquor and wood; for processing certain perfumes;
vanillin, and camphor; in treating industrial
wastes; in the rapid drying of varnishes and printing
inks; and in the deodorizing of feathers.
Carcinogenicity
Ozone has been positive as a
genotoxic substance in certain assay systems, but the results
are inconsistent. For example, in vitro
assays have noted that ozone can induce bacterial mutations,
plasmid DNA strand breakage, chromatid and chromosome
aberrations in lymphocytes, and a doubling of the frequency
of preneoplastic variants compared with control cultures.
However, in vivo assays of similar end points produced mixed
results. For example, alveolar macrophages
from rats exposed to 270–800 ppb ozone developed chromatid
damage, but no chromosomal changes. In human
subjects exposed to 500 ppb ozone (6–10 h), a slight increase
in sister chromatid exchange persisted for ≤6 weeks.
In contrast, no significant changes in chromosome or chromatid
breaks were observed in lymphocytes of subjects
exposed for 4 h to 400 ppb. Cultured human epidermal cells exposed to 500 ppb ozone for 10 min showed no evidence
of DNA strand breakage.
Other investigators have suggested that chronic ozone
exposure may facilitate the development of benign pulmonary
tumors (adenomas) in mice and other hyperplastic
nodules in the lungs of nonhuman primates.
As is true of hyperoxia, ozone exposure may enhance or
retard lung tumorigenesis by other agents in rodents, depending
on the exposure protocol.
Other investigators have suggested that in vitro assays
indicate ozone may exert indirect genotoxic effects. Ozone
has been purported to affect the integrity of immune system
defenses against tumor development and progression
(1073, 1074). In addition, arylamines found in tobacco
smoke (e.g., naphthylamine and toluidine isomers) can be
chemically altered by brief exposures (1 h) to 100–400 ppb
ozone. The unidentified stable products of this reaction cause
single-strand DNA breaks in cultured human lung cells
equivalent to that produced by 100 rad of irradiation.
However, an in vivo cocarcinogenicity study failed to find
similar effects.
Environmental Fate
Ozone formed from anthropogenic sources such as from car
vehicle emissions in the troposphere can travel long distances. Ozone formation and scavenging by other chemicals such as
NO is in constant daily flux. There are times when solar radiation
is high, such as on hot days or during rush hour, which
produces elevated ozone levels and times such as during the
evening when the rate of ozone scavenging exceeds ozone
production, resulting in less ozone in the atmosphere. Ozone
concentrations in the eastern United States are often more than
80 ppb in the warm spring and summer months, though ozone
levels in the western United States are lower.
storage
Work with ozone should be conducted in a fume hood to prevent
exposure by inhalation. Ozone is usually produced in the laboratory with a ozone generator,
and care should be taken to ensure adequate ventilation in the area where the ozone generation
equipment is located. Because of the possibility of the generation of explosive ozonides,
ozonolysis reactions should always be conducted in a fume hood behind a safety shield.
Shipping
UN1955 Compressed gas, toxic, n.o.s, Inhalation
Hazard Zone A, Hazard Class: 2.3; Labels: 2.3-Poisonousgas,
5.1-Oxidizer, Technical name required, Inhalation Hazard
Zone A. Cylinders must be transported in a secure upright
position, in a well-ventilated truck. Protect cylinder and labels
from physical damage. The owner of the compressed gas cylinder
is the only entity allowed by federal law (49CFR) to
transport and refill them. It is a violation of transportation regulations
to refill compressed gas cylinders without the express
written permission of the owner.
Toxicity evaluation
The biochemical mechanism of ozone-induced lung injury is
due to the reaction of the highly reactive O3 with biological
macromolecules such as protein, lipids, nucleic acids, and
carbohydrates. The resulting formation of reactive free-radical intermediates from the oxidization of thiol-containing amino
acids forms disulfide bonds and methionine sulfoxide. Polyunsaturated
fatty acids in cell membrane lipid bilayers are
a major target and react with the ozone to induce lipid peroxidation
to affect membrane fluidity and induce cellular
damage. Nucleic acids can also be affected by the oxidative
potential of ozone. The primary site of injury is the lung, and
the injury is characterized by pulmonary congestion, edema,
and hemorrhage. The area of the lung that is particularly
sensitive to ozone is the junction of the bronchioles and the
alveoli. Effects of ozone on lung function vary greatly between
individuals. Antioxidants present in the respiratory lining
protect against oxidative injury.
Incompatibilities
A powerful oxidizer. A severe explosion
hazard when exposed to shock or heat, especially solid or liquid
form. Spontaneously decomposes to oxygen under ordinary
conditions; heating increases oxygen production. Reacts
with all reducing agents; combustibles, organic, and inorganic
oxidizable materials; and can form products that are highly
explosive. Incompatible with alkenes, aniline, benzene, bromine,
ether, ethylene, and hydrogen bromide; nitric oxide; stibine.
Attacks metals except gold and platinum.
Waste Disposal
Vent to atmosphere. Use a
licensed professional waste disposal service to dispose of
this material. All federal, state, and local environmental
regulations must be observed. Return refillable compressed
gas cylinders to supplier.
Check Digit Verification of cas no
The CAS Registry Mumber 10028-15-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,0,0,2 and 8 respectively; the second part has 2 digits, 1 and 5 respectively.
Calculate Digit Verification of CAS Registry Number 10028-15:
(7*1)+(6*0)+(5*0)+(4*2)+(3*8)+(2*1)+(1*5)=46
46 % 10 = 6
So 10028-15-6 is a valid CAS Registry Number.
InChI:InChI=1/O3/c1-3-2
10028-15-6Relevant articles and documents
OZONE GENERATION IN THE 214-nm PHOTOLYSIS OF OXYGEN AT 25 degree C.
Horowitz,Von Helden,Simon,Crutzen,Moortgat
, p. 4956 - 4960 (1988)
Ozone formation in the 214-mm photolysis of oxygen at pressures ranging from 380 to 1300 Torr was investigated. The rates of ozone formation increase with the square of oxygen pressure mirroring the pressure dependence of the absorption cross sections of oxygen. This observation demonstrates the importance of the collision-induced changes in oxygen absorbance and points to a need to examine the role of oxygen dimer (O//2)//2 in reactions initiated by its photodissociation. Because of the high dilution of ozone, its formation was found to be linear with time even though, on the average, its rate of photolysis exceeded the rate of its generation from oxygen. The quantum yield of ozone formation was 1. 86 plus or minus 0. 17 independent of O//2 pressure.
Kinetics and products of the reaction O2(1σ g+) with N2O
Dunlea, Edward J.,Talukdar, Ranajit K.,Ravishankara
, p. 989 - 1007 (2010)
Previous studies have suggested that the reaction of O2O 2(1σg+) + N2O / NO + NO2 may be a significant source of NOx in the atmosphere if the branching ratio of this channel is greater than ?1%. We have measured the overall rate coefficient (k1) for the reaction of O 2O2(1σg+) with N2O to be k1(295 K) = (1.06±0.14)×10 -13 cm3 molecule-1 s-1 at 295 K and k1(T) = (7.48±1.66)×10-14 exp[(87±40).T] cm3 molecule-1 s-1 as a function of temperature over therange 210-370 K. The yields of NO, NO 2 or O3 that are possible reaction products from the title reaction were undetectably small. Also, the net loss of N2O from the title reaction was negligibly small. We report upper limits for the yields for the production of NOx, the production of O3 and the loss of N2O (all at 298 K) to be-4, -3, and-3,respectively. We conclude that the reaction of O2O2(1σ g+) + N2O is neither a significant source of NOx in the atmosphere nor a significant sink for N2O. by Oldenbourg Wissenschaftsverlag.
Electrosynthesis and physicochemical properties of PbO2 films
Velichenko,Amadelli,Benedetti,Girenko,Kovalyov,Danilov
, p. C445-C449 (2002)
An electrochemical and X-ray diffraction study has been conducted on the formation of lead dioxide deposits on platinum, from nitric acid solutions, as a function of potential and temperature. It has been shown that these parameters strongly influence the morphology and electrocatalytic activity of the PbO2 films. The electrodeposition process is satisfactorily described by an electrochemical, chemical, electrochemical mechanism: (i) H2O → OHads + H+ + e-; (ii) Pb2+ + OHads → Pb(OH)2+; (iii) Pb(OH)2+ + H2O → PbO2 + 3H+ + e-; the second electron transfer stage and Pb2+ diffusion control the dioxide formation in the lower and higher overpotential range, respectively. Temperature and potential (or current) are important parameters in the electrodeposition process. Depending on the potential region, the process can be kinetically or diffusion controlled. In an acid electrolyte, where mainly the β-PbO2 modification is electrodeposited, the amount of α-phase impurity increases with increasing potential in the kinetically controlled region and decreases in the diffusion controlled domain. In addition, relatively low electrodeposition potentials and high temperatures favor an increase of the crystallite size with preferred crystallographic orientation for both α- and β-PbO2 modifications. The temperature of the growth solution affects the crystallinity of the resulting oxide deposits and has a marked effect on their performance as anodes in processes at high positive potentials such as ozone generation.
Systematic trends in the vibrational frequency shifts of some molecules trapped in amorphous water ice
Vigasin,Schriver-Mazzuoli,Schriver
, p. 101 - 113 (2003)
This paper focuses on systematic examination of the vibrational frequency shifts of some molecules trapped in water ices. It is shown that for the bands, for which the laboratory taken data are available, the magnitude and the sign of a vibrational shift for the molecules trapped in water ice can be approximately predicted using empirical correlations with macroscopic properties of the host. These results can be useful for identification of the carriers of absorption in matrix spectroscopy, for the study of intermolecular interactions, for a number of applications involving remote spectroscopic sensing of molecular species in the atmosphere and in space.
Synergistic effects of sonolysis combined with ozonolysis for the oxidation of azobenzene and methyl orange
Destaillats, Hugo,Colussi,Joseph, Jiju M.,Hoffmann, Michael R.
, p. 8930 - 8935 (2000)
The extent of mineralization, measured as total organic carbon (TOC) losses, during the 500 kHz sonication of azobenzene or methyl orange solutions increased from 20 to > 80% in the presence of O3. The abatement of the total organic load by the joint action of ultrasound and O2 amounted to chemical synergism. Since TOC losses were not enhanced by ozonation followed by sonication and ground-state oxygen atoms, synergism likely involved the fast oxidation by O3 of free radical or unsaturated species produced by ·OH radical attack on otherwise refractory products. Some of these products were possibly saturated mono- and dicarboxylic acids, known to be resistant to O3 oxidation. Benzoquinone and nitrobenzene were rapidly and completely mineralized by the combined oxidation treatment. Thus, direct ozonation of unsaturated sonolytic byproducts also accounted for part of the observed improvement of the extent of mineralization. The anomalous kinetic behavior of the sonochemical degradation of benzoquinone during the absence of O3 was accounted for by its high reactivity toward the inert HO2· and O2-· radicals.
Photochemical removal of NO, NO2, and N2O by 146 nm Kr2excimer lamp in N2 at atmospheric pressure
Tsuji, Masaharu,Kamo, Naohiro,Kawahara, Takashi,Kawahara, Masashi,Senda, Makoto,Hishinuma, Nobuyuki
, p. 277 - 284 (2009)
The photochemical removal of NO, N02, and N20 was investigated in N2 using a 146 nm Kr2 (25mWcm 2) excimer lamp. The results obtained were compared with those obtained using 172 nm Xe2 (50
Lattice oxygen of PbO2induces crystal facet dependent electrochemical ozone production
Jiang, Wenbin,Wang, Shibin,Liu, Jia,Zheng, Haiyang,Gu, Yu,Li, Wenwen,Shi, Huaijie,Li, Suiqin,Zhong, Xing,Wang, Jianguo
, p. 9010 - 9017 (2021)
The on-site production of ozoneviaelectrochemical water electrolysis has attracted increasing interest because of its security and efficiency. However, the underlying mechanism of the facet effect and the influence of lattice oxygen on β-PbO2for electrochemical ozone production (EOP) remain unclear. Here, β-PbO2-120 nanorods (β-PbO2-120 NRs) were prepared to investigate the mechanism of the facet effect and the influence of lattice oxygen during the EOP process. The β-PbO2-120 NRs assembled as an anode in a membrane electrode assembly show a remarkable EOP performance. Measurements usingin situ18O isotope-labeling differential electrochemical mass spectrometry confirm that all three oxygen atoms in the ozone originate from the lattice oxygen of β-PbO2. Theoretical calculations verify that the EOP reaction pathway on β-PbO2follows the lattice oxygen mechanism (LOM), and surface lattice oxygen migration and coupling to O2/O3are favorable on the (101) and (110) surfaces of β-PbO2. Different reaction mechanisms are proposed on the two surfaces, and (101) exhibits higher reactivity for O2and the formation of O3. This valuable insight into the facet effect and LOM of metal oxide-based electrocatalysts can be extended to other applications.
Conversion of SO2 to SO3 Facilitated by in Situ UV Photolysis of H2CO and SO2 in an O2 Matrix at 12 K
Green, Martina,Lee, Edward K. C.
, p. 6470 - 6475 (1986)
The photooxidation product distributions observed in photolyses of H2CO and H2CO*SO2 molecular complexes in O2 matrices at λ = 270-420 nm are compared.Photodissociation of H2CO produces RO2 species, i.e., HO2 and HC(O)OO radicals, which then efficiently oxidize SO2 to SO3 (and H2SO4).This process occurs with an efficiency of ca. 0.7 +/- 0.3 per H2CO*SO2 molecular complex photodissociated.Various photooxidation mechanisms are considered.Implications of the low-temperature/matrix photooxidation results on atmospheric photooxidation of SO2 by RO2 species are discussed.
Molecular-scale characterization of the reaction of ozone with decanethiol monolayers on Au(111)
Poirier, Gregory E.,Herne, Tonya M.,Miller, C. Cameron,Tarlov, Michael J.
, p. 9703 - 9711 (1999)
The chemical reaction of ozone with decanethiol monolayers on Au(111) was characterized using X-ray photoelectron spectroscopy and scanning tunneling microscopy. Our results show that exposure to ozone results in oxidation of the thiol terminus. The reaction initiates at the domain boundary network of the alkanethiol monolayer and propagates into the domains. Above a threshold surface oxygen content, the monolayer converts to a two-dimensional fluid that can subsequently recrystallize to a commensurate monolayer of partially oxidized thiol. Further exposure to ozone results in conversion of the monolayer to a fluid phase and a 10% to 30% expansion of the Au lattice at the Au - thiol interface with concomitant formation of Au islands. Our results demonstrate that crystallographic defects in monolayer films can play an important role in their chemical reactions.
Kinetics and Mechanism of the BrO+HO2 Reaction
Larichev, Michael,Maguin, Francoise,Bras, Georges Le,Poulet, Gilles
, p. 15911 - 15918 (1995)
Using the discharge flow-mass spectrometric technique, the kinetics and mechanism of the BrO+HO2 reaction have been investigated in the temperature range 233-344 K.With an excess of HO2 over BrO, the rate constant was found to be k1=(4.77+/-0.3
