Various chromium-containing catalysts were tested for the total oxidation of trichloroethylene (TCE) as a model reaction for the catalytic combustion of chlorinated organic pollutants: A spinel-type cobalt chromite (CoCr{sub}2O{sub}4) among others was proven to be a very promising catalyst showing higher activity and higher CO{sub}2 selectivity than traditional alumina supported chromia. Even if both Cr{sup}(3+) and Cr{sup}(6+) species were observed on the surface of CoCr{sub}2O{sub}4, the C{sup}(6+) species was stable under reducing environment. The presence of Cr{sup}(3+)-Cr{sup}(6+) pair sites and the effect of redax treatments on the activity were investigated to explain the nature of possible active sites for TCE decomposition. Higher selectivity to CO{sub}2 of CoCr{sub}2O{sub}4 was ascribed to the abundance of its Cr{sup}(3+) species, together with its activity for water gas shift reaction.
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