On the role of carbon-oxygen surface complexes in the carbon/oxygen reaction mechanism
- Pennsylvania State Univ., University Park, PA (United States)
In the past, attempts to characterize the reactivity of carbon materials have led to conclusions regarding the importance of active sites and carbon-oxygen (C(O)) complexes in the carbon/O{sub 2} reaction mechanism. More recently, questions have been raised concerning the possibility of oxygen presence on the basal plane during gasification. Studies with disordered (turbostratic) carbons (e.g., polymer-derived carbons and coal chars) revealed that the quantity of C(O) complexes on the surface at gasification conditions exceeds significantly the quantities formed during low-temperature chemisorption. One of the possible mechanistic explanations for this experimental fact is the so-called {open_quotes}spillover effect{close_quotes} whereby oxygen atoms, chemisorbed on the edge sites of carbon crystallites, migrate ({open_quotes}spill over{close_quotes}) from the edges to the basal plane. Spillover is the process that occurs when active species, C(O) complexes, are formed on one type of sites (e.g., edges), and are subsequently transferred to another type of sites (e.g., basal plane). Although the basal plane does not participate directly in carbon gasification, it serves as an additional reservoir of oxygen. A larger quantity of oxygen resides on the surface at higher temperatures, because spillover is an activated process. The objective of this work was to pursue an understanding of the role of basal-plane and edge complexes in the formation of carbon monoxide and carbon dioxide.
- OSTI ID:
- 433107
- Report Number(s):
- CONF-960376--
- Journal Information:
- Preprints of Papers, American Chemical Society, Division of Fuel Chemistry, Journal Name: Preprints of Papers, American Chemical Society, Division of Fuel Chemistry Journal Issue: 1 Vol. 41; ISSN 0569-3772; ISSN ACFPAI
- Country of Publication:
- United States
- Language:
- English
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