Template-free method to prepare porous Cu-containing nanotubes with a good catalytic performance for styrene epoxidation

摘要

Cu-containing nanotubes with a large surface area and pore volume were prepared by using nanoscrolls derived from K_4Nb_6O_(17) as a support and a subsequent thermal transformation of Cu-containing nanoscrolls into Nb_2O_5 nanotubes. The method is facile and template-free. The catalytic performance of the resulted Cu-containing nanotubes was evaluated for styrene epoxidation in the presence of tert-butyl hydroperoxide (TBHP) and H_2O_2, respectively. It was found that Cu-containing nanotubes displayed a relative good catalytic performance with a styrene oxide (SO) selectivity of 46.9% by TBHP and a much higher SO selectivity of 94.6% by H_2O_2. Two possible mechanisms were put forward to explain the different catalytic behaviors in the two types of oxidation systems. Because of the thermal transformation of nanoscrolls into nanotubes, nanoscrolls may be a new kind of promising support for the design and assembly of novel heterogeneous catalysts.