TiO 2 aerogel–Cu-BTC metal-organic framework composites for enhanced photon absorption

Novel composites containing titania aerogel and Cu-BTC metal-organic framework (MOF) were synthesized via sol-gel route and characterized by various techniques. The concentration of MOF in composites was varied between 5 and 20 weight% with respect to titania precursor. The presence of prominent peaks of Cu-BTC in the small-angle X-ray diffraction (SAXD) analysis confirmed the incorporation of MOF in the composite. This is further confirmed by Fourier Transform Infrared Spectral analysis (FTIR), energy-dispersive X-ray spectroscopy (EDS) analysis and elemental mapping studies. The Brunauer-Emmett-Teller(BET) surface area was found to vary between 204 and 240 m2 g−1 depending upon MOF concentration in the composites. It was noted that the pore distribution was found to be narrowed on increasing MOF concentration in the composite. Transmission Electron Microscope (TEM) and Field Emission Scanning Electron Microscope (FE-SEM) images revealed the nanoporous morphology of the composites. The incorporation of MOF to TiO2 aerogel showed a significant increase of absorption in the visible region. These properties suggest that TiO2 aerogel-Cu-BTC composites are promising materials for photovoltaic and photocatalytic applications.