Adsorption and Reaction of Acetaldehyde over CeO(X)(111) Thin Films

This study reports the interaction of acetaldehyde with well-ordered CeO{sub X}(111) thin film surfaces. The fully oxidized CeO{sub 2}(111) surface shows a weak interaction with acetaldehyde with the sole desorption product (TPD) being the parent molecule at 210 K. The chemisorbed molecule binds to the surface as the {eta}{sub 1}-acetaldehyde species rather than through a bridge-bonded dioxy configuration. Acetaldehyde chemisorbs strongly on reduced CeO{sub 2-X}(111) with nonrecombinative and recombinative acetaldehyde desorbing at 405 and 550-600 K, respectively. Deoxygenation and dehydration also occur, producing ethylene and acetylene at 580 and 620 K, respectively. Acetaldehyde initially adsorbs in the {eta}{sub 1} configuration and then converts to a carbanion species with both C=C and C=O bond character above 300 K.