Lattice Matching Strategy to Construct Highly Active hcp-Co Phase for Fischer–Tropsch Synthesis

Lattice matching facilitates the growth of heteroatoms on a stable substrate with similar lattice spacing, thereby offering a solution for synthesizing inherently unstable active atoms while simultaneously exhibiting novel properties. In this study, this concept was used to construct highly active while metastable hcp-Co active phases for the Fischer–Tropsch Synthesis (FTS) reaction. The formation of hcp-Co species was achieved by initially depositing wurtzite CoO on ZnO (ZnO@h-CoO), which exhibited only a lattice mismatch of 0.18%, followed by reduction with H2 to yield ZnO@hcp-Co. Experimental and Density Functional Theory (DFT) calculations suggest that ZnO can decrease the surface energy of h-CoO through a strong interface bond. In situ XRD performed under H2 conditions confirms that ZnO@h-CoO is a viable precursor for the hcp-Co active phase in Fischer–Tropsch synthesis, particularly when the reduction temperature is below 400 °C. The ZnO@h-CoO catalyst demonstrates significantly enhanced catalytic performance compared with impregnated Co/ZnO catalysts due to the presence of hcp-Co sites. This work provides comprehensive insights into the phase transition process of metastable h-CoO, under various atmospheres and temperatures, presenting a practical approach for acquiring the hcp-Co active phase in Fischer–Tropsch synthesis.