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Organic Linker Defines the Excited‐State Decay of Photocatalytic MIL‐125(Ti)‐Type Materials
Author(s) -
Santaclara Jara G.,
Nasalevich Maxim A.,
Castellanos Sonia,
Evers Wiel H.,
Spoor Frank C. M.,
Rock Kamila,
Siebbeles Laurens D. A.,
Kapteijn Freek,
Grozema Ferdinand,
Houtepen Arjan,
Gascon Jorge,
Hunger Johannes,
van der Veen Monique A.
Publication year - 2016
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201501353
Subject(s) - photoexcitation , photocatalysis , excited state , photochemistry , materials science , titanium , absorption (acoustics) , spectroscopy , chemistry , atomic physics , physics , catalysis , organic chemistry , metallurgy , composite material , quantum mechanics
Recently, MIL‐125(Ti) and NH 2 ‐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), NH 2 ‐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 NH 2 ‐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 NH 2 ‐MIL‐125(Ti), the electron donation of which extends the lifetime of the photoexcited state substantially.