Relationship between the structure and dehydrogenation of alcohols/hydrogenation of nitroarenes and base catalysis performance of Co–N–C catalyst

A Co–N–C catalyst was fabricated via pyrolysis–reduction process. Dehydrogenation/hydrogenation and base catalysis performances of the Co–N–C catalyst were investigated by using the reductive coupling of nitroarenes with alcohols and aldol condensation as probe reactions. Various characterizations were performed to explore effects of reduction and pyrolysis temperature on the structure/composition and basicity of the Co–N–C catalyst, and the relationship between structure-dehydrogenation/hydrogenation and base catalysis performance was discussed accordingly. Two different structures of Co–N–C catalyst (Co–N–C/C 3 N 4 and Co–N–C/CNT) were obtained in different pyrolysis temperature. Co–N–C-600 with C 3 N 4 exhibits very weak catalytic performance owe to its poor pore system and active phase. Dehydrogenation/hydrogenation behaviors of Co–N–C/CNT depend on the amount of Co–N, graphitic N in Co–N–C, while the basicity of Co–N–C is closely related to the content of N species, particularly pyrrolic N and pyridinic N. The appropriate pyrolysis temperature benefits the formation of active species, developed pore organization and strong basicity. And, the H 2 reduction improve dehydrogenation/hydrogenation activity of Co–N–C/CNT because reduction can destroy carbon coating layers to expose more Co–N species and promote the transformation of N species to graphitic N. Meanwhile, H 2 reduction increases the contents of graphitic N and reduces the content of pyrrolic N and pyridinic N, thus weakening catalyst basicity and consequently reducing base catalytic activity of Co–N–C/CNT.