Organic linker defines the excited-state decay of photocatalytic MIL-125(Ti)-type materials
J. Garcia Santaclara (TU Delft - ChemE/Catalysis Engineering)
Maxim Nasalevich (TU Delft - ChemE/Catalysis Engineering)
S. Castellanos Ortega (TU Delft - ChemE/Catalysis Engineering)
W.H. Evers (TU Delft - QN/van der Zant Lab, Kavli institute of nanoscience Delft, TU Delft - QN/Mol. Electronics & Devices)
Frank C M Spoor (TU Delft - ChemE/Opto-electronic Materials)
L.D.A. Siebbeles (TU Delft - ChemE/Opto-electronic Materials)
F. Kapteijn (TU Delft - ChemE/Catalysis Engineering)
F.C. Grozema (TU Delft - ChemE/Opto-electronic Materials)
A.J. Houtepen (TU Delft - ChemE/Opto-electronic Materials)
J. Gascon (TU Delft - ChemE/Catalysis Engineering)
M.A. van der Veen (TU Delft - ChemE/Catalysis Engineering)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
Recently, MIL-125(Ti) and NH2-MIL-125(Ti), two titanium-based metal–organic frameworks, have attracted significant research attention in the field of photocatalysis for solar fuel generation. This work reveals that the differences between these structures are not only based on their light absorption range but also on the decay profile and topography of their excited states. In contrast to MIL-125(Ti), NH2-MIL-125(Ti) shows markedly longer lifetimes of the charge-separated state, which improves photoconversion by the suppression of competing decay mechanisms. We used spectroelectrochemistry and ultrafast spectroscopy to demonstrate that upon photoexcitation in NH2-MIL-125(Ti) the electron is located in the Ti-oxo clusters and the hole resides on the aminoterephthalate unit, specifically on the amino group. The results highlight the role of the amino group in NH2-MIL-125(Ti), the electron donation of which extends the lifetime of the photoexcited state substantially.