Supported metal catalysts have found numerous applications in many catalytic reactions, including Fischer-Tropsch synthesis. Metal dispersion, metal reducibility, catalytic performance and catalyst stability are usually strongly affected by the interaction of active phase and support. A strong metal support interaction has been previously reported for titania supported catalysts. In this work, a series of titania supported cobalt catalysts promoted via deposition of a layer of carbon nitride were prepared, characterized and tested in Fischer-Tropsch synthesis. The catalytic performance of freshly activated catalysts was an interplay of cobalt dispersion and reducibility. Deposition of carbon nitride on the surface of titania resulted in a noticeable enhancement of cobalt dispersion, while it hindered to some extent cobalt reducibility. The non-promoted cobalt catalysts exhibited noticeable deactivation in Fischer-Tropsch synthesis. The catalyst deactivation was due to the progressive encapsulation of cobalt active phase by TiO2 during the reaction. A carbon nitride layer on the TiO2 surface stabilized cobalt nanoparticles and prevented encapsulation of active sites by TiO2 species. The stability was significantly enhanced on all titania supported cobalt catalysts promoted with carbon nitride.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: We thank the financial support by National Natural Science foundation of China (21203255, 21473259), Hubei Natural Science Foundation (2018CFB556), Technology Foundation for Selected Overseas Chinese Scholar, Ministry of Personnel of China (BZY14037), Fundamental Research Funds for the Central Universities (South-Central University for Nationalities, CZY19006). AK thanks the South Central University for Nationalities for funding his research stay in Wuhan.