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Heterogeneous catalysis dioxide

In furnaces using residual oils, heterogeneous catalysis is a possible route for the conversion of S02 to S03. Sulfur dioxide and molecular oxygen will react catalytically on steel surfaces and vanadium pentoxide (deposited from vanadium compounds in the fuel). Catalytic reactions may also occur at lower temperatures where the equilibrium represented by reaction (8.94) favors the formation of S03. [Pg.455]

Pruden, A.L. and Ollis, D.F. Degradation of chloroform by photoassisted heterogeneous catalysis in dilute aqueous suspensions of titanium dioxide. Environ. Sci. Technol., 17(10) 628-631, 1983. [Pg.1711]

Because of the rapid developments in the field of heterogeneous catalysis, the material reviewed here is exclusively dedicated to selective oxidations. No attention is given to total oxidations or combustion processes (including the problem of automotive exhaust gases). There is one exception, however the oxidation of sulphur dioxide to trioxide. Work on vanadate catalysts for this reaction is close to research on selective catalysts and therefore included. [Pg.123]

Table 2.3. Examples of Heterogeneous Catalysis in Dense-Phase Carbon Dioxide... [Pg.37]

Keywords electron transfer, heterogeneous catalysis, photochemistry, photoelectrochemistry, Titanium dioxide... [Pg.183]

Heterogeneous catalysis also occurs in the oxidation of gaseous sulfur dioxide to gaseous sulfur trioxide. This process is especially interesting because it illustrates both positive and negative consequences of chemical catalysis. [Pg.742]

The solubility of carbon dioxide in aqueous and non-aqueous solutions depends on its partial pressure (via Henry s law), on temperature (according to its enthalpy of solution) and on acid-base reactions within the solution. In aqueous solutions, the equilibria forming HCO3 and CO3 depend on pH and ionic strength the presence of metal ions which form insoluble carbonates may also be a factor. Some speculation is made about reactions in nonaqueous solutions, and how thermodynamic data may be applied to reduction of CO2 to formic acid, formaldehyde, or methanol by heterogenous catalysis, photoreduction, or electrochemical reduction. [Pg.8]

Investigation of carbon dioxide catalytic activation is explored by a variety of subdisciplines (homogeneous catalysis, heterogeneous catalysis, electrocatalysis/photoelectrocatalysis), often with little cross-citation of work. This situation created a need to bring together the leading researchers to provide an overview of methods and accomplishments to date. [Pg.219]

Heterogeneous catalysis is activated when the catalyst slides against itself or other materials, e.g. ceramics. Oxidation reactions of hydrogen, carbon monoxide and methane were demonstrated as being enhanced by rubbing platinum, palladium and silver, respectively [29-31], and the reduction of carbon dioxide is enhanced by the rubbing of iron oxide [32],... [Pg.251]

SCHEME 6.11 Heterogeneous catalysis of the copolymerization of carbon dioxide and propylene carbonate on Zn-based catalysts. [Pg.264]

Spinels. Spinels are a group of materials with relevant properties in heterogeneous catalysis. They have the general formula AB2O4 where A represents a divalent metal ion and B corresponds to a trivalent metal ion. MgAl204 can for example be used as catalyst for reducing sulphur dioxide emissions or as catalytic support material . ... [Pg.267]

Heterogeneous catalysis is also utilized in the catalytic converters in automobile exhaust systems. The exhaust gases, containing compounds such as nitric oxide, carbon monoxide, and unburned hydrocarbons, are passed through a converter containing beads of solid catalyst (see Fig. 12.16). The catalyst promotes the conversion of carbon monoxide to carbon dioxide, hydrocarbons to carbon dioxide and water, and nitric oxide to nitrogen gas to lessen the environmental impact of the exhaust gases. However, this beneficial catalysis can, unfortunately, be accompanied by the unwanted catalysis of the oxidation of SO2 to SO3, which reacts with the moisture present to form sulfuric acid. [Pg.572]


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