LAUSR

Abstract The adsorption behaviors of formaldehyde (CH2O) molecule on anatase TiO2 (2 1 1) surface are studied by the first-principles method. Besides monodentate and bidentate adsorption configurations, there is an interesting found that both stable bidentate adsorption involved surface bridging O22 atom will induce a surface bond breaking. The π bond of formaldehyde is also opening. Combination of these two ingredients produces the most stable adsorption. Moreover, those two configurations are essentially the same just oxygen atom of molecule OF and the surface O22 interchanged. Furthermore, their bonding properties are analyzed in detail through the density of state. It is revealed that covalent and ionic bonding coexist in the oxygen atoms involved in adsorption.