Center for Materials Crystallography, Department of Chemistry, Aarhus University, Langelangsgade 140, 8000, Aarhus C, Denmark.
ChemSusChem. 2016 Mar 8;9(5):532-9. doi: 10.1002/cssc.201501199. Epub 2016 Jan 28.
TiO2@SnO2 hybrid nanocomposites were successfully prepared in gram scale using a dual-stage hydrothermal continuous-flow reactor. Temperature and pH in the secondary reactor were found to selectively direct nucleation and growth of the secondary material into either heterogeneous nanocomposites or separate intermixed nanoparticles. At low pH, 2 nm rutile SnO2 nanoparticles were deposited on 9 nm anatase TiO2 particles; the presence of TiO2 was found to suppress formation of larger SnO2 particles. At high pH SnO2 formed separate particles and no deposition on TiO2 was observed. Ball-milling of TiO2 and SnO2 produced no TiO2@SnO2 composites. This verifies that the composite particles must be formed by nucleation and growth of the secondary precursor on the TiO2 . High concentration of secondary precursor led to formation of TiO2 particles embedded in aggregates of SnO2 nanoparticles. The results demonstrate how nanocomposites may be produced in high yield by green chemistry.
TiO2@SnO2 杂化纳米复合材料在克级规模上通过双级水热连续流反应器成功制备。在二级反应器中，温度和 pH 值被发现可以选择性地引导二级材料的成核和生长，形成异质纳米复合材料或分离的混合纳米颗粒。在低 pH 值下，2nm 锐钛矿 SnO2 纳米颗粒沉积在 9nm 金红石 TiO2 颗粒上；TiO2 的存在被发现抑制了更大 SnO2 颗粒的形成。在高 pH 值下，SnO2 形成了单独的颗粒，并且没有观察到 TiO2 上的沉积。TiO2 和 SnO2 的球磨没有产生 TiO2@SnO2 复合材料。这验证了复合颗粒必须通过在 TiO2 上的二次前体的成核和生长形成。高浓度的二次前体导致 TiO2 颗粒嵌入在 SnO2 纳米颗粒的聚集体中。结果表明，通过绿色化学可以高产率地制备纳米复合材料。
