First principles calculations on the structures, electronic and magnetic properties of the TM_n@W₁₂O₃₆ (TM=Mn, Fe, Co and Ni, n=1-4) clusters

Transition metal (Mn, Fe, Co and Ni)-doped tungsten oxides nanoparticles with magnetic properties may be applied in various catalysts such as water treatment as they are easy to be recycled. Structural, electronic and magnetic properties of TMn@W12O36 (TM=Mn, Fe, Co and Ni, n=1-4) clusters have been calculated at PBE level. The results reveal that the centers of the TM1-3 clusters are in accordance with that of the W12O36 clusters while the TM4 clusters deviate obviously from the center of the W12O36 cages. All TMn@W12O36 clusters exhibit slightly less structural stability and obviously more chemical reactivity than the W12O36 clusters. Mulliken spin densities of a TM atom embedded are almost kept except for the Ni@W12O36 clusters. The spin densities of TMn clusters in the TM3@W12O36 and TM4@W12O36 clusters are offset. The magnetic TM modification strategy is helpful to design recyclable tungsten oxide catalysts.