Band edges positions prediction of the of Ag nanocluster-decorated titania surfaces and their relationship to NO and NO2 interaction from first-principles calculations

C. I. N. MORGADE; SCHVVAL, A.B.; G. GARCÍA; CABEZA, G. F.

JOURNAL OF MOLECULAR GRAPHICS & MODELLING.

ELSEVIER SCIENCE INC

Lugar: Amsterdam; Año: 2023

1093-3263

Metalnanoclusters deposited on oxides have been widely used in photocatalysisplaying an important role in the design of model catalysts with applications inheterogeneous catalysis. In particular, we are interestedin the potential activity of these cluster-supported systems for the removal of nitrogen oxides either by possiblecatalytic reduction and/or by their adsorption. In this work, usingfirst-principles methods, we evaluate the main characteristics of Agn(n = 1 - 4) nanoclusters isolated anddeposited on anatase TiO2(101) and rutile TiO2(110)surfaces. Our results indicate that they are preferably adsorbed on rutile surface. The different formation energy at each surface can be explained using a Bader chargeanalysis. Particularly for Ag4the lowest formation energy is obtained for tetrahedral geometry while theisolated Ag4 geometry is planar. Smallsilver deposits placed superficially on titania surfaces modify its electronicstructures and improve the conduction band edges positions for possible NOreduction. Band edges positions with respect to the vacuum potential have beenstudied. Thecomparison of the conduction band minimum with the reduction potentials of NO/N2O and N2O/N2 shows that they are higher, being Ag3 onrutile and Ag1, Ag2 and Ag4P on anatase betterfor NO reduction. To complete the analysis, the calculation of workfunction, energy gap, ionization energy and electron affinity are relevantsince they allow the location of semiconductor band edges at point of zerocharge. Finally,the adsorption of nitrogen oxides is studied where the NO2adsorption is favored over NO.