Reactivity of Stoichiometric and Defective TiO_2 (110) Surfaces toward DCOOD Decomposition

摘要

The effect of defects on TiO_2 (110) on the decomposition of DCOOD was investigated by temperature-programmed reaction spectroscopy (TPRS). Different concentrations of anion vacancy defects were created on the TiO_2 (110) surface by electron beam irradiation in order to minimize structural damage to the surface. For comparison, defects were also created by argon bombardment. The oxidation state produced by the defects and their concentrations were characterized by X-ray photoelectron spectroscopy (XPS). The selectivity of the reaction for the production of carbon monoxide, formaldehyde, and D_2 was increased significantly by the defects. An appreciable decrease in the temperature for CO and D_2CO formation on the defective surfaces produced by electron beam irradiation was observed, compared to the stoichiometric surface, suggestive of changes in the kinetics of the decomposition. The presence of isotopic exchange in the products provides evidence for the formation of formyl intermediates during DCOOD decomposition.