TM-CmHm organometallics (TM=Fe, Co, Ni, Cu, Zn and m=4, 5, 6) for highly efficient Pt-free catalytic activation of O2 molecule

Abstract

The interaction between oxygen molecule (O2) and organometallic compounds has always been an interesting research topic because O2 plays a benchmark role for demonstrating the activity level of the organometallic-based catalysts. In this work, the effect of various transition metals (TMs) on the interaction between O2 and TM-CmHm organometallic compounds is investigated using density functional theory (DFT) calculations. Our results show that the TM decoration enhances the reactivity of CmHm, however, it is more effective in the case of Zn-decorated on the CmHm systems. Also, the O2 adsorption energy and O–O bond length activation is considerably changed with changing the TM atoms in the TM-CmHm organometallics compounds. Consistent with the prediction of chemical hardness descriptors, the best catalytic activity toward O2 activation is related to the Zn-decorated on CmHm systems. The Zn-CmHm organometallic compounds strengthen the interaction between O2 and Zn atom, resulting in increased adsorption energy; the corresponding O–O bond length is also elongated. Moreover, the energy barrier of the O2 activation on the Zn-C6H6 is less than 0.50 eV, representing that the reaction can proceed easily at room temperature. Because the bond length of the O2 correlates with its catalytic activation, the results can provide a new application of organometallic-based catalysts.