Role of surface phosphorus complexes in the oxidation of activated carbons

摘要

Activated carbons materials have attracted considerable attention because their interesting application in many fields, such as catalysis, gas and liquid phase adsorption and gas and energy storage. The carbon materials present an additional advantage since they can be prepared from different carbonaceous precursors, as agricultural wastes or by-products, that are abundant, environmentally friendly disposal and cost decrease associated with activated carbon production. Consequently, there is a great research effort in this direction.However, the use of carbon materials in catalysis is limited since they would gasify to CO2 (or CO) in the presence of oxygen at relatively low temperatures. Nevertheless, it has been shown that it is possible to prepare carbon materials with a relatively large amount of phosphorus on the carbon surface by chemical activation of lignocellulosic materials with phosphoric acid. This activation procedure lead to phosphorus surface complexes, in form of COPO3, CPO3 and C3P groups, which remain very stable on the carbon surface, at relatively high temperatures, and confer to the carbon a high oxidation resistance and high acidity, increasing the catalytic applications in which these catalysts can be used.