title: Electronic origins of photocatalytic activity in d0 metal organic frameworks.
abstract: Metal-organic frameworks (MOFs) containing d(0) metals such as NH2-MIL-125(Ti), NH2-UiO-66(Zr) and NH2-UiO-66(Hf) are among the most studied MOFs for photocatalytic applications. Despite structural similarities, we demonstrate that the electronic properties of these MOFs are markedly different. As revealed by quantum chemistry, EPR measurements and transient absorption spectroscopy, the highest occupied and lowest unoccupied orbitals of NH2-MIL-125(Ti) promote a long lived ligand-to-metal charge transfer upon photoexcitation, making this material suitable for photocatalytic applications. In contrast, in case of UiO materials, the d-orbitals of Zr and Hf, are too low in binding energy and thus cannot overlap with the π* orbital of the ligand, making both frontier orbitals localized at the organic linker. This electronic reconfiguration results in short exciton lifetimes and diminishes photocatalytic performance. These results highlight the importance of orbital contributions at the band edges and delineate future directions in the development of photo-active hybrid solids.
authors.affiliation: Catalysis Engineering, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, Delft, The Netherlands.
authors.forename: Maxim A
authors.initials: MA
authors.lastname: Nasalevich
authors.affiliation: Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Hendon
authors.affiliation: Catalysis Engineering, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, Delft, The Netherlands.
authors.forename: Jara G
authors.initials: JG
authors.lastname: Santaclara
authors.affiliation: Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
authors.forename: Katrine
authors.initials: K
authors.lastname: Svane
authors.affiliation: Catalysis Engineering, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, Delft, The Netherlands.
authors.forename: Bart
authors.initials: B
authors.lastname: van der Linden
authors.affiliation: Laboratory of Magnetic Resonance, International Tomography Center, Institutskaya 3A, Novosibirsk 630090, Russia.|Novosibirsk State University, Novosibirsk 630090, Russia.
authors.forename: Sergey L
authors.initials: SL
authors.lastname: Veber
authors.affiliation: Laboratory of Magnetic Resonance, International Tomography Center, Institutskaya 3A, Novosibirsk 630090, Russia.|Novosibirsk State University, Novosibirsk 630090, Russia.
authors.forename: Matvey V
authors.initials: MV
authors.lastname: Fedin
authors.affiliation: Optoelectronic Materials, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands.
authors.forename: Arjan J
authors.initials: AJ
authors.lastname: Houtepen
authors.affiliation: Catalysis Engineering, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, Delft, The Netherlands.
authors.forename: Monique A
authors.initials: MA
authors.lastname: van der Veen
authors.affiliation: Catalysis Engineering, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, Delft, The Netherlands.
authors.forename: Freek
authors.initials: F
authors.lastname: Kapteijn
authors.affiliation: Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.|Department of Materials Science and Engineering, Yonsei University, Seoul, Korea.
authors.forename: Aron
authors.initials: A
authors.lastname: Walsh
authors.affiliation: Catalysis Engineering, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, Delft, The Netherlands.
authors.forename: Jorge
authors.initials: J
authors.lastname: Gascon