2.2.2. Preparation of UiO-66(Zr/Ti)-NH2
The as-prepared UiO-66(Zr)-NH2 nanoparticles (0.09 g) were dispersed in DMF (60 mL) in an Al-wrapped vessel. Afterward, TiCl3 (6.79 g) was added to the vessel and the mixture was heated at 85 °C under vacuum for five days. The resulting UiO-66(Zr/Ti)-NH2 powder was alternately washed with DMF and CHCl3 three times.
For comparison, we used Ti4+ (TiCl4solution) to exchange Zr4+, and the prepared MOF was denoted UiO-66(Zr/Ti)-NH2-Ti4+.