Tunable CO Dissociation Assisted by H2 over Cobalt Species: A Mechanistic Study by In-situ DRIFTS

Fischer-Tropsch synthesis (FTS) is an important heterogeneous catalytic process that can effectively reduce human dependence on the non-renewable petroleum resources. Cobalt is a crucial active metal center in most catalysts, which effectively catalyzes syngas into valuable products such as liquid fuels. On this basis, we systematically investigated the adsorption of CO on the surface of different cobalt species and its dissociation characteristics assisted by H-2 are studied by the in-situ DRIFTS. For the metallic cobalt phase, H-2-assisted CO dissociation not only possessed the FTS activity, but also inhibited the CO disproportionation reaction. However, for the CoO phase, the bidentate carbonate species were decomposed into CO2. In addition, CoO presented a high-chain propagation ability than that of Co under the same operation conditions. Co2O3 and Co3O4 also exhibited similar CO dissociation patterns with the assistance of H-2. However, different from CoO phase, formate species also formed under the H-2 atmosphere over these two Co species. In summary, CO dissociation would be well tuned via the assistance of H-2 as demonstrated by the in-situ DRIFTS. This work provides a new sight on the rational design of efficient cobalt catalysts toward the FTS processes.

Automated summary

The study found that H-2 can effectively assist in the dissociation of CO on the surface of different cobalt species, thereby regulating the reaction of Fischer-Tropsch synthesis process, improving the selectivity of products and catalytic activity.