Honeycomb-like porous Ce–Cr oxide/N-doped carbon nanostructure: Achieving high catalytic performance for the selective oxidation of cyclohexane to KA oil

In heterogeneous catalysis , developing robust catalysts and preventing the metal leaching during the reactions still remain challenging. Herein, a porous honeycomb-like nanostructure with bimetallic Ce–Cr oxide supported on N-doped carbon was prepared via a facile in-situ pyrolysis method. The prepared catalyst was highly active, selective, and stable in the transformation of cyclohexane to KA oil with H 2 O 2 as the oxidant. The N-doped carbon served as an excellent support for the metal nanoparticles and greatly promoted their dispersion, and displayed a comparable or superior catalytic activity compared to the other traditional supports. It was found that the pyridinic N and pyrrolic N species of N-doped carbon were the main active sites for the metal immobilization , and the strong electronic interaction between N-doped carbon and Ce–Cr oxide was formed. The results revealed that the increased low-valence metal species might be responsible for the improved catalytic activity, and EPR analysis indicated that the hydroxyl radicals played a crucial role during the oxidation process . Besides, the catalyst can be easily separated and still remained stable after recycling seven times, making it a promising candidate for the catalytic oxidation of cyclohexane to KA oil under mild conditions.