Tunable Morphologies of Fe-Embedded Cr-MOF Derived Catalyst for Efficient CO2 Hydrogenation

We report a stable MOF-derived bimetallic FeCrC_x catalyst for heterogeneous catalytic reactions. Using ReaxFF molecular dynamics, we uncover the atomistic pathways that drive the thermal conversion of MIL-101(Cr) and its Fe-loaded analogue. The presence of iron in the framework lowers its stability, resulting in higher mass loss and fragmentation of the aromatic linkers during thermal transformation. Our simulations predict the formation of highly dispersed Fe─Cr core-shell nanoparticles with a Cr core when transformed at high temperatures. However, our simulations show that Fe nanoparticles are embedded in a chromium-carbon matrix at lower temperatures. This MIL-101(Cr)-derived FeCrC_x (Fe and Cr embedded in a residual carbon-rich environment) catalyst was then experimentally prepared and demonstrated activity in the aqueous phase for CO₂ hydrogenation to methanol. Significantly, the MOF-derived FeCrC_x catalyst transformed at 500 °C showed approximately five times better yield than the catalyst treated at 400 °C, which we attribute to the Fe─Cr core-shell particles in the former. We are confident that our integrated computational-experimental strategy will accelerate the discovery of MOF-derived bimetallic catalysts and unlock their potential in a broad spectrum of applications.