CaltechAUTHORS
  A Caltech Library Service

X-ray Spectroscopic Characterization of Co(IV) and Metal-Metal Interactions in Co_4O_4: Electronic Structure Contributions to the Formation of High-Valent States Relevant to the Oxygen Evolution Reaction

Hadt, Ryan G. and Hayes, Dugan and Brodsky, Casey N. and Ullman, Andrew M. and Casa, Diego M. and Upton, Mary H. and Nocera, Daniel G. and Chen, Lin X. (2016) X-ray Spectroscopic Characterization of Co(IV) and Metal-Metal Interactions in Co_4O_4: Electronic Structure Contributions to the Formation of High-Valent States Relevant to the Oxygen Evolution Reaction. Journal of the American Chemical Society, 138 (34). pp. 11017-11030. ISSN 0002-7863. https://resolver.caltech.edu/CaltechAUTHORS:20180612-142321731

[img] PDF (Full experimental details, supporting tables and figures, and Cartesian coordinates of DFT-optimized geometries) - Supplemental Material
See Usage Policy.

3503Kb

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20180612-142321731

Abstract

The formation of high-valent states is a key factor in making highly active transition-metal-based catalysts of the oxygen evolution reaction (OER). These high oxidation states will be strongly influenced by the local geometric and electronic structures of the metal ion, which are difficult to study due to spectroscopically active and complex backgrounds, short lifetimes, and limited concentrations. Here, we use a wide range of complementary X-ray spectroscopies coupled to DFT calculations to study Co(III)_4O_4 cubanes and their first oxidized derivatives, which provide insight into the high-valent Co(IV) centers responsible for the activity of molecular and heterogeneous OER catalysts. The combination of X-ray absorption and 1s3p resonant inelastic X-ray scattering (Kβ RIXS) allows Co(IV) to be isolated and studied against a spectroscopically active Co(III) background. Co K- and L-edge X-ray absorption data allow for a detailed characterization of the 3d-manifold of effectively localized Co(IV) centers and provide a direct handle on the t_(2g)-based redox-active molecular orbital. Kβ RIXS is also shown to provide a powerful probe of Co(IV), and specific spectral features are sensitive to the degree of oxo-mediated metal-metal coupling across Co_4O_4. Guided by the data, calculations show that electron-hole delocalization can actually oppose Co(IV) formation. Computational extension of Co_4O_4 to CoM_3O_4 structures (M = redox-inactive metal) defines electronic structure contributions to Co(IV) formation. Redox activity is shown to be linearly related to covalency, and M(III) oxo inductive effects on Co(IV) oxo bonding can tune the covalency of high-valent sites over a large range and thereby tune E^0 over hundreds of millivolts. Additionally, redox-inactive metal substitution can also switch the ground state and modify metal-metal and antibonding interactions across the cluster.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1021/jacs.6b04663DOIArticle
https://pubs.acs.org/doi/suppl/10.1021/jacs.6b04663PublisherSupporting Information
ORCID:
AuthorORCID
Hadt, Ryan G.0000-0001-6026-1358
Hayes, Dugan0000-0003-4171-5179
Nocera, Daniel G.0000-0001-5055-320X
Chen, Lin X.0000-0002-8450-6687
Alternate Title:X-ray Spectroscopic Characterization of Co(IV) and Metal-Metal Interactions in Co4O4: Electronic Structure Contributions to the Formation of High-Valent States Relevant to the Oxygen Evolution Reaction
Additional Information:© 2016 American Chemical Society. Received: May 5, 2016. Published: August 12, 2016. Work at ANL was supported by funding from the Division of Chemical Sciences, Biosciences, Office of Basic Energy Science (OBES), DOE through Grant DE-AC02-06CH11357. Synchrotron facilities were provided by the Advanced Photon Source (APS) and Advanced Light Source (ALS) operated by DOE BES. Work at Harvard was performed under a grant from the U.S. DOE Office of Science (DE-SC0009758). D.H. is supported by the Joseph J. Katz Postdoctoral Fellowship at Argonne National Laboratory (ANL). C.N.B. acknowledges the National Science Foundation’s Graduate Research Fellowship. We acknowledge Sungsik Lee for assistance in making Co K-edge measurements and Robert Schoenlein and Amy Cordones-Hahn for assistance in making Co L-edge measurements. We acknowledge Edward Solomon, Michael Mara, Thomas Kroll, and Bryce Anderson for helpful discussions. We gratefully acknowledge the computing resources provided on Blues and Fusion, both high-performance computing clusters operated by the Laboratory Computing Resource Center at ANL. The authors declare no competing financial interest.
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-AC02-06CH11357
Department of Energy (DOE)DE-SC0009758
Argonne National LaboratoryUNSPECIFIED
NSF Graduate Research FellowshipUNSPECIFIED
Issue or Number:34
Record Number:CaltechAUTHORS:20180612-142321731
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20180612-142321731
Official Citation:X-ray Spectroscopic Characterization of Co(IV) and Metal–Metal Interactions in Co4O4: Electronic Structure Contributions to the Formation of High-Valent States Relevant to the Oxygen Evolution Reaction Ryan G. Hadt, Dugan Hayes, Casey N. Brodsky, Andrew M. Ullman, Diego M. Casa, Mary H. Upton, Daniel G. Nocera, and Lin X. Chen Journal of the American Chemical Society 2016 138 (34), 11017-11030 DOI: 10.1021/jacs.6b04663
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87022
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:12 Jun 2018 21:46
Last Modified:03 Oct 2019 19:51

Repository Staff Only: item control page