Lowering Electrocatalytic CO2Reduction Overpotential Using N-Annulated Perylene Diimide Rhenium Bipyridine Dyads with Variable Tether Length

Josh D.B. Koenig; Zachary S. Dubrawski; Keerthan R. Rao; Janina Willkomm; Benjamin S. Gelfand; Chad Risko; Warren E. Piers; Gregory C. Welch

doi:10.1021/jacs.1c09481

Lowering Electrocatalytic CO₂Reduction Overpotential Using N-Annulated Perylene Diimide Rhenium Bipyridine Dyads with Variable Tether Length

Josh D.B. Koenig, Zachary S. Dubrawski, Keerthan R. Rao, Janina Willkomm, Benjamin S. Gelfand, Chad Risko, Warren E. Piers, Gregory C. Welch

Chemistry

Research output: Contribution to journal › Article › peer-review

14 Scopus citations

Abstract

We report the design, synthesis, and characterization of four N-annulated perylene diimide (NPDI) functionalized rhenium bipyridine [Re(bpy)] supramolecular dyads. The Re(bpy) scaffold was connected to the NPDI chromophore either directly [Re(py-C0-NPDI)] or via an ethyl [Re(bpy-C2-NPDI)], butyl [Re(bpy-C4-NPDI)], or hexyl [Re(bpy-C6-NPDI)] alkyl-chain spacer. Upon electrochemical reduction in the presence of CO2 and a proton source, Re(bpy-C2/4/6-NPDI) all exhibited significant current enhancement effects, while Re(py-C0-NPDI) did not. During controlled potential electrolysis (CPE) experiments at Eappl = -1.8 V vs Fc+/0, Re(bpy-C2/4/6-NPDI) all achieved comparable activity (TONco ∼25) and Faradaic efficiency (FEco ∼94%). Under identical CPE conditions, the standard catalyst Re(dmbpy) was inactive for electrocatalytic CO2 reduction; only at Eappl = -2.1 V vs Fc+/0 could Re(dmbpy) achieve the same catalytic performance, representing a 300 mV lowering in overpotential for Re(bpy-C2/4/6-NPDI). At higher overpotentials, Re(bpy-C4/6-NPDI) both outperformed Re(bpy-C2-NPDI), indicating the possibility of coinciding electrocatalytic CO2 reduction mechanisms that are dictated by tether-length and overpotential. Using UV-vis-nearIR spectroelectrochemistry (SEC), FTIR SEC, and chemical reduction experiments, it was shown that the NPDI-moiety served as an electron-reservoir for Re(bpy), thereby allowing catalytic activity at lower overpotentials. Density functional theory studies probing the optimized geometries and frontier molecular orbitals of various catalytic intermediates revealed that the geometric configuration of NPDI relative to the Re(bpy)-moiety plays a critical role in accessing electrons from the electron-reservoir. The improved performance of Re(bpy-C2/4/6-NPDI)dyads at lower overpotentials, relative to Re(dmbpy), highlights the utility of chromophore electron-reservoirs as a method for lowering the overpotential for CO2 conversion.

Original language	English
Pages (from-to)	16849-16864
Number of pages	16
Journal	Journal of the American Chemical Society
Volume	143
Issue number	40
DOIs	https://doi.org/10.1021/jacs.1c09481
State	Published - Oct 13 2021

Bibliographical note

Funding Information:
G. C. W. acknowledges the Canada Research Chairs Program, CFI JELF (34102), NSERC DG (2019-04392), and the University of Calgary. W. E. P. acknowledges the Canada Research Chairs Program. J. K. acknowledges Alberta Graduate Excellence Scholarship (AGES) and NSERC CGS-D scholarship programs. This research was undertaken thanks in part to funding from the Canada First Research Excellence Fund (CFREF). C. R. and K. R. acknowledge funding by the Research Corporation for Science Advancement (RCSA) Cottrell Scholars program (Award No. 24432); computing resources on the Lipscomb High Performance Computing Cluster were provided by the University of Kentucky Information Technology Department and the Center for Computational Sciences (CCS).

Publisher Copyright:
© 2021 American Chemical Society.

ASJC Scopus subject areas

Catalysis
Chemistry (all)
Biochemistry
Colloid and Surface Chemistry

Access to Document

10.1021/jacs.1c09481

Cite this

@article{7dc6d45ad42e4457a4501ecfe4ee3b05,

title = "Lowering Electrocatalytic CO2Reduction Overpotential Using N-Annulated Perylene Diimide Rhenium Bipyridine Dyads with Variable Tether Length",

abstract = "We report the design, synthesis, and characterization of four N-annulated perylene diimide (NPDI) functionalized rhenium bipyridine [Re(bpy)] supramolecular dyads. The Re(bpy) scaffold was connected to the NPDI chromophore either directly [Re(py-C0-NPDI)] or via an ethyl [Re(bpy-C2-NPDI)], butyl [Re(bpy-C4-NPDI)], or hexyl [Re(bpy-C6-NPDI)] alkyl-chain spacer. Upon electrochemical reduction in the presence of CO2 and a proton source, Re(bpy-C2/4/6-NPDI) all exhibited significant current enhancement effects, while Re(py-C0-NPDI) did not. During controlled potential electrolysis (CPE) experiments at Eappl = -1.8 V vs Fc+/0, Re(bpy-C2/4/6-NPDI) all achieved comparable activity (TONco ∼25) and Faradaic efficiency (FEco ∼94%). Under identical CPE conditions, the standard catalyst Re(dmbpy) was inactive for electrocatalytic CO2 reduction; only at Eappl = -2.1 V vs Fc+/0 could Re(dmbpy) achieve the same catalytic performance, representing a 300 mV lowering in overpotential for Re(bpy-C2/4/6-NPDI). At higher overpotentials, Re(bpy-C4/6-NPDI) both outperformed Re(bpy-C2-NPDI), indicating the possibility of coinciding electrocatalytic CO2 reduction mechanisms that are dictated by tether-length and overpotential. Using UV-vis-nearIR spectroelectrochemistry (SEC), FTIR SEC, and chemical reduction experiments, it was shown that the NPDI-moiety served as an electron-reservoir for Re(bpy), thereby allowing catalytic activity at lower overpotentials. Density functional theory studies probing the optimized geometries and frontier molecular orbitals of various catalytic intermediates revealed that the geometric configuration of NPDI relative to the Re(bpy)-moiety plays a critical role in accessing electrons from the electron-reservoir. The improved performance of Re(bpy-C2/4/6-NPDI)dyads at lower overpotentials, relative to Re(dmbpy), highlights the utility of chromophore electron-reservoirs as a method for lowering the overpotential for CO2 conversion. ",

author = "Koenig, {Josh D.B.} and Dubrawski, {Zachary S.} and Rao, {Keerthan R.} and Janina Willkomm and Gelfand, {Benjamin S.} and Chad Risko and Piers, {Warren E.} and Welch, {Gregory C.}",

note = "Funding Information: G. C. W. acknowledges the Canada Research Chairs Program, CFI JELF (34102), NSERC DG (2019-04392), and the University of Calgary. W. E. P. acknowledges the Canada Research Chairs Program. J. K. acknowledges Alberta Graduate Excellence Scholarship (AGES) and NSERC CGS-D scholarship programs. This research was undertaken thanks in part to funding from the Canada First Research Excellence Fund (CFREF). C. R. and K. R. acknowledge funding by the Research Corporation for Science Advancement (RCSA) Cottrell Scholars program (Award No. 24432); computing resources on the Lipscomb High Performance Computing Cluster were provided by the University of Kentucky Information Technology Department and the Center for Computational Sciences (CCS). Publisher Copyright: {\textcopyright} 2021 American Chemical Society.",

year = "2021",

month = oct,

day = "13",

doi = "10.1021/jacs.1c09481",

language = "English",

volume = "143",

pages = "16849--16864",

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T1 - Lowering Electrocatalytic CO2Reduction Overpotential Using N-Annulated Perylene Diimide Rhenium Bipyridine Dyads with Variable Tether Length

AU - Koenig, Josh D.B.

AU - Dubrawski, Zachary S.

AU - Rao, Keerthan R.

AU - Willkomm, Janina

AU - Gelfand, Benjamin S.

AU - Risko, Chad

AU - Piers, Warren E.

AU - Welch, Gregory C.

N1 - Funding Information: G. C. W. acknowledges the Canada Research Chairs Program, CFI JELF (34102), NSERC DG (2019-04392), and the University of Calgary. W. E. P. acknowledges the Canada Research Chairs Program. J. K. acknowledges Alberta Graduate Excellence Scholarship (AGES) and NSERC CGS-D scholarship programs. This research was undertaken thanks in part to funding from the Canada First Research Excellence Fund (CFREF). C. R. and K. R. acknowledge funding by the Research Corporation for Science Advancement (RCSA) Cottrell Scholars program (Award No. 24432); computing resources on the Lipscomb High Performance Computing Cluster were provided by the University of Kentucky Information Technology Department and the Center for Computational Sciences (CCS). Publisher Copyright: © 2021 American Chemical Society.

PY - 2021/10/13

Y1 - 2021/10/13

N2 - We report the design, synthesis, and characterization of four N-annulated perylene diimide (NPDI) functionalized rhenium bipyridine [Re(bpy)] supramolecular dyads. The Re(bpy) scaffold was connected to the NPDI chromophore either directly [Re(py-C0-NPDI)] or via an ethyl [Re(bpy-C2-NPDI)], butyl [Re(bpy-C4-NPDI)], or hexyl [Re(bpy-C6-NPDI)] alkyl-chain spacer. Upon electrochemical reduction in the presence of CO2 and a proton source, Re(bpy-C2/4/6-NPDI) all exhibited significant current enhancement effects, while Re(py-C0-NPDI) did not. During controlled potential electrolysis (CPE) experiments at Eappl = -1.8 V vs Fc+/0, Re(bpy-C2/4/6-NPDI) all achieved comparable activity (TONco ∼25) and Faradaic efficiency (FEco ∼94%). Under identical CPE conditions, the standard catalyst Re(dmbpy) was inactive for electrocatalytic CO2 reduction; only at Eappl = -2.1 V vs Fc+/0 could Re(dmbpy) achieve the same catalytic performance, representing a 300 mV lowering in overpotential for Re(bpy-C2/4/6-NPDI). At higher overpotentials, Re(bpy-C4/6-NPDI) both outperformed Re(bpy-C2-NPDI), indicating the possibility of coinciding electrocatalytic CO2 reduction mechanisms that are dictated by tether-length and overpotential. Using UV-vis-nearIR spectroelectrochemistry (SEC), FTIR SEC, and chemical reduction experiments, it was shown that the NPDI-moiety served as an electron-reservoir for Re(bpy), thereby allowing catalytic activity at lower overpotentials. Density functional theory studies probing the optimized geometries and frontier molecular orbitals of various catalytic intermediates revealed that the geometric configuration of NPDI relative to the Re(bpy)-moiety plays a critical role in accessing electrons from the electron-reservoir. The improved performance of Re(bpy-C2/4/6-NPDI)dyads at lower overpotentials, relative to Re(dmbpy), highlights the utility of chromophore electron-reservoirs as a method for lowering the overpotential for CO2 conversion.

AB - We report the design, synthesis, and characterization of four N-annulated perylene diimide (NPDI) functionalized rhenium bipyridine [Re(bpy)] supramolecular dyads. The Re(bpy) scaffold was connected to the NPDI chromophore either directly [Re(py-C0-NPDI)] or via an ethyl [Re(bpy-C2-NPDI)], butyl [Re(bpy-C4-NPDI)], or hexyl [Re(bpy-C6-NPDI)] alkyl-chain spacer. Upon electrochemical reduction in the presence of CO2 and a proton source, Re(bpy-C2/4/6-NPDI) all exhibited significant current enhancement effects, while Re(py-C0-NPDI) did not. During controlled potential electrolysis (CPE) experiments at Eappl = -1.8 V vs Fc+/0, Re(bpy-C2/4/6-NPDI) all achieved comparable activity (TONco ∼25) and Faradaic efficiency (FEco ∼94%). Under identical CPE conditions, the standard catalyst Re(dmbpy) was inactive for electrocatalytic CO2 reduction; only at Eappl = -2.1 V vs Fc+/0 could Re(dmbpy) achieve the same catalytic performance, representing a 300 mV lowering in overpotential for Re(bpy-C2/4/6-NPDI). At higher overpotentials, Re(bpy-C4/6-NPDI) both outperformed Re(bpy-C2-NPDI), indicating the possibility of coinciding electrocatalytic CO2 reduction mechanisms that are dictated by tether-length and overpotential. Using UV-vis-nearIR spectroelectrochemistry (SEC), FTIR SEC, and chemical reduction experiments, it was shown that the NPDI-moiety served as an electron-reservoir for Re(bpy), thereby allowing catalytic activity at lower overpotentials. Density functional theory studies probing the optimized geometries and frontier molecular orbitals of various catalytic intermediates revealed that the geometric configuration of NPDI relative to the Re(bpy)-moiety plays a critical role in accessing electrons from the electron-reservoir. The improved performance of Re(bpy-C2/4/6-NPDI)dyads at lower overpotentials, relative to Re(dmbpy), highlights the utility of chromophore electron-reservoirs as a method for lowering the overpotential for CO2 conversion.

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