Theoretical Modeling of the Structure of Surface Niobium Sites Based on Solid-State 93Nb NMR

In this work niobium oxide clusters on the surface of Al₂O₃ are modeled using DFT calculations. ⁹³Nb NMR parameters of modeled clusters were computed with the GIPAW method. The niobia system under consideration represents high niobium loading on the surface of the support. The niobium atoms are highly coordinated and linked to the other niobia polyhedra by one or two bonds. The most of the niobium oxide particles has a coordination number of six. The correlations found between ⁹³Nb NMR parameters and coordination environment are discussed.

Keywords:
niobium catalysts, surface sites, ⁹³Nb NMR, first-principles calculations. 
УДК 544.176:546.882:544.183.25

Theoretical Modeling of the Structure of Surface Niobium Sites Based on Solid-State 93Nb NMR