Unlocking mixed oxides with unprecedented stoichiometries from heterometallic metal-organic frameworks for the catalytic hydrogenation of CO2

Their complex surface chemistry and high oxygen lattice mobilities placemixed-metal oxides among themost important families ofmaterials. Modulation of stoichiometry in mixed-metal oxides has been shown to be a very powerful tool for tuning optical and catalytic properties. However, accessing different stoichiometries is not always synthetically possible. Here, we show that the thermal decomposition of the recently reported metal-organic framework MUV-101( Fe, Ti) results in the formation of carbon-supported titanomaghemite nanoparticles with an unprecedented Fe/Ti ratio close to 2, not achievable by soft-chemistry routes. The resulting titanomaghemite phase displays outstanding catalytic activity for the production of CO from CO2 via the reverse water-gas shift (RWGS) reaction with CO selectivity values of ca. 100% and no signs of deactivation after several days on stream. Theoretical calculations suggest that the reaction proceeds through the formation of COOH* species, favoring in this way CO over other byproducts.

Automated summary

Mixed-metal oxides have complex surface chemistry and high oxygen lattice mobilities, making them important materials. Modulating stoichiometry in mixed-metal oxides can tune optical and catalytic properties, although accessing different stoichiometries is not always possible synthetically.