Surface Organo-Iron Chemistry Towards Efficient Reverse Water-Gas Shift Catalysis

Abstract

The low-temperature reverse water-gas shift (LT-RWGS) is a critical and energy effective technology for syngas production and the mitigation of anthropogenic carbon emissions. Developing efficient and well-defined catalysts for the LT-RWGS, from which structure-activity relationships can be drawn, is a significant challenge. Herein we describe how the identification of the grafting properties of tetramesityldiiron (Fe₂Mes₄) helps with designing tailored and highly efficient catalysts of PtFe@SiO₂ composition. To that end, a molecular analogue, Fe₂Mes₃OSi(O^tBu)₃, was synthesized and characterized by X-ray diffraction, ⁵⁷Fe-Mössbauer and ¹H-NMR spectroscopy. The results confirmed that tetramesityldiiron grafts onto silica via selective displacement of a single mesityl ligand, forming Fe₂Mes₃@SiO₂, while steric hindrance likely prevents secondary interactions with surface siloxide bridges. This work highlights the potential of tetramesityldiiron as a versatile precursor for synthesizing bimetallic MFe@SiO₂ systems, enabling the rational development of highly efficient LT-RWGS and CO₂ hydrogenation catalysts.