Density Functional Theory Study On The Atomic Reactivity Of Noble Metal On The Surface Of Anatase TiO₂?101?

The supported noble metals catalysts are widely used in a variety of photocatalytic reactions and industrial processes for the highly reactivity,selectivity and stability.Since they are expensive and scarce,a great number of researches are aimed at reducing the size of precious metal particles and increasing their quantum size effects.In recent years,some research groups have successfully prepared some single-atom catalysts which maintain a certain degree of its high activity,reaction selectivity and stability.In this work,density functional theory is used to research the adsorption of some small molecules on the anatase TiO2(101)surfaces with Au and Pt single atom supported and CO oxidation reaction and formic acid dissociation on both of the surfaces.The main calculations are as follows:1.Au and Pt single atom tend to adsorb between the two coordination oxygen 2cO of the TiO2(101).The interaction between the single-atom Au and the substrate on the surface is weaker than Pt,therefore Au atoms may leave the stable adsorption site and migrate to another site in some conditions.The supported single atom causes a certain degree of activation of the five coordination titanium 5cTi,which act as an active site in the reaction.2.In the CO oxidation reaction,CO tends to absorb on the noble metal single-atom by C atom while O2 bond with noble metal single-atom and 5cTi of TiO2(101).When the oxidation reaction occurs on both surfaces,the activation energy is 1.05 eV of Au1/TiO2 and 0.95 eV of Pt1/TiO2 respectively,which broken of O-O as the rate-limiting step of the reaction.Therefore,the oxidation reaction of CO on the Ptj/TiO2 surface is more likely to occur on the Au1/TiO2 surface.3.Formic acid tends to adsorbed on the 5cTi of Au1/TiO2 or Au atom by carbonyl oxygen adsorption than surface of clean TiO2.The formation of HCOO and H atoms by H-O bond cleavage by H-O bond on the surface of Au1/TiO2(101)spontaneously.The formation of CO2 by C-O bond breakage is more favorable than the formation of CO and CO by C-H and C-O bond breakage.