The synthesis of a core-shell hybrid composite micro-sphere with controllable homogenous or heterogeneous multi-shell structure by multiple-growth via a combination method

Scheme of the working method route. The SSiO2, the MSiO2 and MTiO2 were synthesized and either SSiO2, MSiO2 or MTiO2 were used as the seed beads to be coated with one or multiple different shells composed of either solid silica, mesoporous silica or mesoporous titanium oxide. Layer A: MSiO2, layer B: MTiO2, layer C: SSiO2, layer AC: MSiO2/SSiO2, layer CA: SSiO2/MSiO2, layer AB: MSiO2/MTiO2, ACC: MSiO2/SSiO2/SSiO2, ABC: MSiO2/MTiO2/SSiO2, CAB: SSiO2/MSiO2/MTiO2, AAA: MSiO2/MSiO2/MSiO2.