Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published January 28, 2019 | Supplemental Material + Published
Journal Article Open

Nanoporous Gold as a Highly Selective and Active Carbon Dioxide Reduction Catalyst


Electrochemical conversion of CO_2 into useful chemicals is a promising approach for transforming CO_2 into sustainably produced fuels and/or chemical feedstocks for industrial synthesis. We report that nanoporous gold (np-Au) films, with pore sizes ranging from 10 to 30 nm, represent promising electrocatalytic architectures for the CO_2 reduction reaction (CO_2RR) due to their large electrochemically active surface area, relative abundance of grain boundaries, and ability to support pH gradients inside the nanoporous network. Electrochemical studies show that np-Au films support partial current densities for the conversion of CO_2 to CO in excess of 6 mA cm^(–2) at a Faradaic efficiency of ∼99% in aqueous electrolytes (50 mM K_2CO_3 saturated with CO_2). Moreover, np-Au films are able to maintain Faradaic efficiency greater than 80% for CO production over prolonged periods of continuous operation (110 h). Electrocatalytic experiments at different electrolyte concentrations demonstrate that the pore diameter of nanoporous cathodes represents a critical parameter for creating and controlling local pH gradients inside the porous network of metal ligaments. These results demonstrate the merits of nanoporous metal films for the CO_2RR and offer an interesting architecture for highly selective electrocatalysis capable of sustaining high catalytic currents over prolonged periods.

Additional Information

© 2018 American Chemical Society. This article is made available for a limited time sponsored by ACS under the ACS Free to Read License, which permits copying and redistribution of the article for non-commercial scholarly purposes. Received: September 17, 2018; Accepted: December 26, 2018; Published: December 26, 2018. This work is done within the Joint Center for Artificial Photosynthesis, a Department of Energy (DOE) Energy Innovation Hub, supported through the Office of Science of the U.S. Department of energy under Award Number De-SC0004993. A.J.W. acknowledges support from the National Science Foundation (NSF) Graduate Research Fellowship Program under Base Award No. 1745301. G.T. acknowledges support from the Swiss National Science Foundation through the Advanced Mobility Fellowship, grant n. P300P2_171417. We gratefully acknowledge critical support and infrastructure provided for this work by the Kavli Nanoscience Institute at Caltech. We thank Matthew S. Hunt of the Kavli Nanoscience Institute at Caltech for assistance with SEM, He FIB, and TEM imaging of nanoporous Au films. Any opinions, findings, and conclusions expressed in this material are those of the authors and do not necessary reflect those of DOE or NSF. Author Contributions: A.J.W., J.S.D., G.T., and H.A.A. conceived of the experimental study. A.J.W. and J.S.D. executed all electrochemical experiments and performed the data analysis. W.-H.C. assisted with gas chromatography and high-pressure liquid chromatography. A.J.W., J.S.D., and H.A.A. wrote the paper, and all authors commented on the manuscript. The authors declare no competing financial interest.

Attached Files

Published - acsaem.8b01570.pdf

Supplemental Material - ae8b01570_si_001.pdf


Files (4.1 MB)
Name Size Download all
1.4 MB Preview Download
2.7 MB Preview Download

Additional details

August 19, 2023
October 19, 2023