Preparation of mesoporous TiO2–C composites as an advanced Ni catalyst support for reduction of 4-nitrophenol

Abstract

To overcome the aggregation and recovery problems and regulate the electronic and chemical properties of Ni nanoparticle catalysts, ordered mesoporous TiO2-C composites have been designed and synthesized as an advanced support, combined with the in situ loading and reduction of Ni nanoparticles via a multi-component co-assembly method. The resulting mesoporous Ni/TiO2-C composites exhibit a large surface area (∼340 m2 g-1), uniform pore size (∼4 nm), moderate pore volume (∼0.23 cm3 g-1), and magnetic saturation value of ∼5.1 emu g-1. The corresponding Ni content was varied in the range from 2 to 13 wt%. More importantly, the mesoporous Ni/TiO2-C composites display high catalytic activity towards the reduction of 4-nitrophenol to 4-aminophenol with NaBH4. The maximum pseudo-first-order reaction rate constant that was obtained with mesoporous Ni/TiO2-C composites (13 wt% Ni) was calculated to be ∼0.40 min-1, which is much higher than that with Ni/C, TiO2-C and Ni/TiO2 composites. In addition, these catalysts were found to be stable for a long time and reusable several times.