Engineering Support Surface to Form Metal Alloy via Atom Migration for Efficient CO Hydrogenation

The size and composition of bimetallic nanoparticles (NPs) are crucial in heterogeneous catalysis owing to their vital role in controlling catalyst reactivity. However, controlling the nucleation of bimetallic NPs is a formidable challenge because the metals are prone to grow independently, forming phase-separated NPs. This study reports that support engineering can tailor the growth of NPs to form a uniformly dispersed bimetallic alloy, enhancing reactivity in catalysis. The surface of a TiN support was functionalized with O atoms to load Fe and Co NPs. For the TiN support calcined at 400 °C for 2 h (TiN–O-2), the obtained FeCo/TiN–O-2 catalyst presents the homogeneous structure of FeCo NP alloys (Co0.7Fe0.3) after treatment in H2, while other FeCo/TiN catalysts show separated Co and Fe phases. In CO hydrogenation, the FeCo/TiN–O-2 catalyst shows the highest CO conversion (77.3%), the highest C5+ selectivity (73.0%), and stability. Characterization results show that the Fe–Co-alloyed NPs (Co0.7Fe0.3) were the active sites over the FeCo/TiN–O-2 catalyst and possess a distinct ability to activate CO and C–C coupling, consistent with the results obtained from density functional theory calculations.