▎ 摘　　要

The selective oxidation of alkylaromatics is of vital importance for the production of high-added-value raw materials. The development of highly efficient heterogeneous catalytic oxidation systems under mild conditions has become an attractive research area. In this work, hybrid Co-Cu-Al layered double hydroxide/graphene (CoCuAl-LDH/graphene) nanocomposites, which were assembled successfully by a one-step coprecipitation route without the use of any additional reducing agents, were used as highly efficient catalysts for the liquid-phase selective oxidation of ethylbenzene using tert-butyl hydroperoxide as the oxidant. A series of characterizations revealed that graphene could stabilize CoCuAl-LDH nanoplatelets effectively in the nanocomposites, and in turn, highly dispersed CoCuAl-LDH could prevent the aggregation of the graphene nanosheets. By fine-tuning the mass ratio of graphene to CoCuAlLDH, such nanocomposites offered a tunable catalytic oxidation performance. In particular, the nanocomposite with the graphene/CoCuAl-LDH mass ratio of 0.4: 1 exhibited a remarkable catalytic performance with a considerable conversion (96.8%) and selectivity to acetophenone (> 95.0 %), which was mainly attributed to the synergism between the active CoCuAl-LDH component and the graphene matrix in the unique hetero-nanostructure. Moreover, the as-assembled nanocomposite catalysts displayed good recyclability and were active for the selective oxidation of other alkylaromatics.