Reversible oxidation/reduction of silver supported on silica aerogel: Influence of the addition of phosphate

被引：17

作者：

Mamontov, G. V. ^{[1
]}

Izaak, T. I. ^{[1
]}

Magaev, O. V. ^{[1
]}

Knyazev, A. S. ^{[1
]}

Vodyankina, O. V. ^{[1
]}

机构：

[1] Tomsk VV Kuibyshev State Univ, Tomsk 634050, Russia

来源：

RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A | 2011年 / 85卷 / 09期

关键词：

silver; oxidation; reduction; silanol groups; phosphates; PARTIAL OXIDATION; SOL-GEL; SELECTIVE OXIDATION; CO OXIDATION; CATALYSTS; CLUSTERS; NANOPARTICLES; FORMALDEHYDE; TEMPERATURE; PROMOTION;

D O I：

10.1134/S0036024411090159

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Ag/SiO(2) and Ag(3)PO(4)/SiO(2) systems supported on silica aerogel were investigated using temperature-programmed reduction (TPR), UV-visible diffuse reflectance spectroscopy (UV-vis DRS), and infrared spectroscopy. The formation of highly dispersed silver particles, uniformly distributed along the surface and stabilized with silanol groups, was observed for Ag/SiO(2) system. Phosphate and silanol groups produce two states of silver localization in phosphate-containing system. The addition of phosphate onto the silica surface leads to the reversible oxidation/reduction of silver in the temperature range of 100-300A degrees C with transitions of silver (particles 10-30 nm in size) to charged states (ions, clusters stabilized by phosphate groups). This reversible behavior of silver is stable, and the amount of silver involved in these processes remained constant (similar to 50%) for the series of consistent cyclic oxidation/reduction treatments.

引用

页码：1540 / 1545

页数：6

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