We studied computationally effects of TeO defects on the distribution of reduced centers, V4+, in the MoVNbTeO M1 bulk material. To this end, we selected a distribution of V and Mo centers, constructed models with periodic boundary conditions, and applied a hybrid DFT approach. We identified two main factors that determine the stability of specific V4+ sites. (i) The proximity of a [TeO]2+ moiety increases the tendency for reducing specific vanadium sites. (ii) The stability of the system is affected by the type and the number of polaron-polaron interactions in which V4+ centers participate. Higher energy penalties result when a reduced center, V4+, is located in the vicinity of a [TeO]2+ vacancy, suggesting an increased propensity of finding fully oxidized vanadium centers, V5+, close to vacant hexagonal channels. We also present linear models that
predict the energetics of systems where all channels are filled by TeO as well as one channel is void of TeO. As fully oxidized V centers, V5+, are considered pertinent to the partial selective oxidation catalysis of short alkanes, tuning the TeO defect density may be crucial for such applications.
License type:
Funding Info:
A*STAR Science and Engineering Research Council, grant no. 1527700033