Two routes to formaldehyde from formic acid on TiO2(001) surfaces

Abstract

Two routes were observed for formaldehyde formation from formic acid on TiO2(001) single crystal surfaces. The first, on reduced surfaces, involves the reduction of formic acid to formaldehyde accompanied by the oxidation of surface Ti cations. Surface oxidation was evident from the increase in the portion of the Ti (2p3/2) signal corresponding to Ti4+ and the decrease in that corresponding to Tix+(0