Stabilizing CoC with HO and K promoter for CO hydrogenation to C hydrocarbons.

The decomposition of cobalt carbide (CoC) to metallic cobalt in CO hydrogenation results in a notable drop in the selectivity of valued C products, and the stabilization of CoC remains a grand challenge. Here, we report an in situ synthesized K-CoC catalyst, and the selectivity of C hydrocarbons in CO hydrogenation achieves 67.3% at 300°C, 3.0 MPa. Experimental and theoretical results elucidate that CoO transforms to CoC in the reaction, while the stabilization of CoC is dependent on the reaction atmosphere and the K promoter. During the carburization, the K promoter and HO jointly assist in the formation of surface C species via the carboxylate intermediate, while the adsorption of C on CoO is enhanced by the K promoter. The lifetime of the K-CoC is further prolonged from 35 hours to over 200 hours by co-feeding HO. This work provides a fundamental understanding toward the role of HO in CoC chemistry, as well as the potential of extending its application in other reactions.