MOF/TiO2 erythrocyte-like heterostructures decorated by noble metals for use in hydrogen photogeneration and pollutant photodegradation

Various metal-organic framework (MOF)/TiO2 heterostructures can be obtained by the partial hydrolysis or calcination of Ti-based MOFs. By adjusting the hydrolysis and calcination steps of NH2-MIL-125 (Ti), a novel photoactive material composed of a MOF (NH2-MIL-125 (Ti)) and TiO2, with a unique erythrocyte shape, was developed. Furthermore, modification of the composition prepared by the partial hydrolysis of NH2-MIL-125 (Ti) (h-MOF) using Au, Ag, Pt, or Pd metal nanoparticles resulted in a significant increase in the efficiency of hydrogen photogeneration. Higher photocatalytic properties are associated with the excitation of MOFs and TiO2, electron transfer, and electron accumulation on nanoparticles. Using the optimal h-MOF/Au photocatalyst, 117 & mu;mol g(-1) h(-1) of hydrogen was produced. On the other hand, composites (ch-MOFs) obtained by calcination of h-MOFs after modification with Au showed high efficiency in the photodegradation of phenol under the threshold of visible radiation (over 42 & mu;mol dm(-3) h(-1)). These properties are related to the generation of electrons by Au nanoparticles because of the corresponding localized surface plasmon resonance. This results in the formation of reactive oxygen species (hydroxyl and superoxide radicals) that decompose organic pollutants. Overall, the obtained materials have high porosity and photocatalytic stability, which are important for photocatalytic processes.

Automated summary

Various metal-organic framework (MOF)/TiO2 heterostructures can be obtained by adjusting the hydrolysis and calcination steps of Ti-based MOFs. Modification of the composition with metal nanoparticles can significantly increase the efficiency of hydrogen photogeneration and the photodegradation of phenol. These improvements are related to the excitation of MOFs and TiO2, electron transfer, electron accumulation on nanoparticles, and the generation of reactive oxygen species.