Exploring the Tunability of Trimetallic MOF Nodes for Partial Oxidation of Methane to Methanol

Density functional theory is used to study the tunability of trigonal prismatic SBUs found in metal-organic frameworks (MOFs) such as MIL-100, MIL-101, and PCN-250/MIL-127 of chemical composition M23+M2+(mu(3)-O)(RCOO)(6) for the partial oxidation of methane to methanol. We performed a combinatorial screening by varying the composition of the trimetallic node (M-1(3+))(2)(M-2(2+)) (where M-1 and M-2 = V, Cr, Mn, Fe, Co, and Ni) and calculated the reaction pathway on both M-1 and M-2 sites. The systematic replacement of metals in the trimetallic cluster allowed us to study the influence of spectator atoms on the catalytic activity of a specific metal site in the cluster toward the N2O activation and C-H bond activation steps of the reaction. In the screening, we identified the top-performing node compositions with predicted barriers lower than those already reported for experimentally tested MOFs with trigonal prismatic SBUs. This work demonstrates the opportunity to tune the catalytic activity of MOFs for redox reactions by changing their metal node composition.