Core–shell structured carbon black@TiO2 microsphere with enhanced visible light photocatalytic activity

The visible light photocatalytic activity of TiO2 is limited by its wide band gap, aggregation of nanoparticles and fast recombination of photo-generated electrons and holes. Carbon black, with its value of low cost, large surface area and good conductivity, was used as a reactive template and a support to prepare the TiO2 and carbon black composites with a core–shell structure. In the composites, TiO2 nanoparticles as a shell uniformly and closely covered on the surface of carbon black microsphere. The molar ratio of carbon black and titanium powder played a crucial role in the structure and composition of the CB@TiO2 composites. The enhanced photocatalytic activity could be attributed to the promotion effects of carbon black, which narrowed the band gap of titania and promoted the adsorption ability for the pollutant.