@article{e046d37b6caa48e88c3b7429975a17fd,
title = "Single-Atom Metal Oxide Sites as Traps for Charge Separation in the Zirconium-Based Metal-Organic Framework NDC-NU-1000",
abstract = "Solvothermal deposition in metal-organic frameworks (MOFs) can be used to mount single-metal-atom catalytic species at chemically reactive sites on hexa-Zr(IV)-oxy(oxo,hydroxo,aqua) nodes in nanoscale crystallites of the MOF NDC-NU-1000 in a self-limiting fashion. Upon photoexcitation of the 1,3,6,8-tetrakis(p-benzoato)pyrene chromophores of the parent framework, charge transfer may occur between the chromophores and the installed heterometal sites. Extended X-ray absorption fine structure studies revealed the single-atom nature of the installed species. A combination of steady-state and ultrafast optical spectroscopy was used to uncover evidence of a charge-separated (CS) state arising in the metalated samples. The relevant dynamics were characterized with transient photoluminescence and femtosecond transient absorption spectroscopy. We find that a titanium-oxy single-atom site gives rise to the longest lived CS species compared to cobalt and nickel in a similar arrangement. This study provides guidance in designing MOF-based catalytic systems for photocatalysis and solar fuel production. ",
author = "Kramar, {Boris V.} and Phelan, {Brian T.} and Sprague-Klein, {Emily A.} and Diroll, {Benjamin T.} and Sungsik Lee and Otake, {Ken Ichi} and Rebecca Palmer and Mara, {Michael W.} and Farha, {Omar K.} and Hupp, {Joseph T.} and Chen, {Lin X.}",
note = "Funding Information: J.T.H. gratefully acknowledges support from the U.S. Department of Energy, Office of Science, Basic Energy Sciences (Grant DE-FG02-87ER13808). L.X.C. acknowledges the support from the Office of Naval Research (ONR) through the Multidisciplinary University Research Initiative (MURI) Grant (N00014-20-1-2517). For the work performed at Northwestern, this work made use of the Integrated Molecular Structure Education and Research Center (IMSERC) facility at Northwestern University, which has received support from the National Science Foundation (NSF, CHE-1048773 and DMR-0521267), the Electron Probe Instrumentation Center (EPIC) and Keck Interdisciplinary Surface Science (Keck-II) facilities of the Northwestern University Atomic and Nanoscale Characterization Experimental (NUANCE) Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-2025633), the International Institute for Nanotechnology (IIN), and Northwestern{\textquoteright}s Materials Research Science and Engineering Center (MRSEC) program (NSF, DMR-1720139). B.V.K. is partially supported by a MURI Grant from ONR (N00014-20-1-2517) to L.X.C. L.X.C., B.T.P., M.W.M, and E.A.S.-K. acknowledge the support from Chemical, Biological and Geological Science program, Basic Energy Science, Office of Science, US Department of Energy, under the Contract DE-AC02-06CH11357. Use of the Center for Nanoscale Materials and Advanced Photon Source, both Office of Science user facilities, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract DE-AC02-06CH11357. MOFkey is as follows: Zr.HVCDAMXLLUJLQZ.MOFkey-v1.csq (NU-1000). Publisher Copyright: {\textcopyright} ",
year = "2021",
doi = "10.1021/acs.energyfuels.1c02623",
language = "English (US)",
journal = "Energy & Fuels",
issn = "0887-0624",
publisher = "American Chemical Society",
}