Optical Excitation of a Nanoparticle Cu/p-NiO Photocathode Improves Reaction Selectivity for CO₂ Reduction in Aqueous Electrolytes
Abstract
We report the light-induced modification of catalytic selectivity for photoelectrochemical CO₂ reduction in aqueous media using copper (Cu) nanoparticles dispersed onto p-type nickel oxide (p-NiO) photocathodes. Optical excitation of Cu nanoparticles generates hot electrons available for driving CO₂ reduction on the Cu surface, while charge separation is accomplished by hot-hole injection from the Cu nanoparticles into the underlying p-NiO support. Photoelectrochemical studies demonstrate that optical excitation of plasmonic Cu/p-NiO photocathodes imparts increased selectivity for CO₂ reduction over hydrogen evolution in aqueous electrolytes. Specifically, we observed that plasmon-driven CO₂ reduction increased the production of carbon monoxide and formate, while simultaneously reducing the evolution of hydrogen. Our results demonstrate an optical route toward steering the selectivity of artificial photosynthetic systems with plasmon-driven photocathodes for photoelectrochemical CO₂ reduction in aqueous media.
Additional Information
© 2020 American Chemical Society. Received: November 25, 2019; Revised: March 3, 2020; Published: March 5, 2020. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award No. DE-SC0004993. G.T. acknowledges support from the Swiss National Science Foundation through the Early Postdoc Mobility Fellowship, grant no. P2EZP2_159101, and the Advanced Mobility Fellowship, grant no. P300P2_171417. A.J.W. acknowledges support from the Resnick Sustainability Institute at the California Institute of Technology and the National Science Foundation (NSF) Graduate Research Fellowship Program under Base Award No. 1745301. We thank Professor Brian McCloskey for sharing the design of the photoelectrochemical cell for temperature-controlled CO₂ reduction experiments. We also thank Dr. Matthias Richter for XPS characterization of p-type NiO and Cu/p-NiO films, which was performed at the Molecular Materials Research Center in the Beckman Institute of the California Institute of Technology. Author Contributions: J.S.D. and H.A.A. conceived the idea, designed the experiments, and wrote the manuscript. J.S.D. performed all photoelectrochemical experiments with assistance from A.J.W. and X.L. J.S.D., G.T., A.J.W., and X.L. fabricated and characterized devices. W.-H.C. performed optical characterization of materials and assisted with calibration and maintenance of gas chromatography equipment. H.A.A. supervised the project. All authors have given approval to the final version of the manuscript. The authors declare no competing financial interest.Attached Files
Supplemental Material - nl9b04895_si_001.pdf
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Additional details
- Eprint ID
- 101732
- Resolver ID
- CaltechAUTHORS:20200305-145718553
- Department of Energy (DOE)
- DE-SC0004993
- Swiss National Science Foundation (SNSF)
- P2EZP2_159101
- Swiss National Science Foundation (SNSF)
- P300P2_171417
- Resnick Sustainability Institute
- NSF Graduate Research Fellowship
- DGE-1745301
- Created
-
2020-03-05Created from EPrint's datestamp field
- Updated
-
2021-11-16Created from EPrint's last_modified field
- Caltech groups
- JCAP, Resnick Sustainability Institute