Accelerating photoelectrochemical CO2RR selectively of C2+ products by integrating Ag/Pd cocatalysts on Cu/Cu2O/CuO heterojunction nanorods

Periyayya Uthirakumar, Hoki Son, Vandung Dao, Yeji Lee, Sunny Yadav, In Hwan Lee

Research output: Contribution to journalArticlepeer-review

Abstract

The Cu-based photoelectrochemical CO2 reduction reaction (PEC–CO2RR) represents a convenient approach for producing value-added C2+ products, aiming to achieve carbon neutrality by reducing greenhouse gas emissions. However, these reactions typically suffer from limited selectivity. In this work, we fabricate Cu/Cu2O/CuO nanorod (CuR)-based heterojunction architectures integrated with Ag and Pd cocatalysts to boost the selectivity of C2+ products. The proposed Cu/Cu2O/CuO/Ag-Pd (CuR/Ag-Pd) photoelectrodes are used as photocathodes to generate a maximum Faradaic efficiency (FE) of C2+ products exceeding 53% by suppressing the hydrogen evolution reaction (HER). The FE improvement is approximately 22-fold (n-propanol), 12-fold (ethanol), 13-fold (acetaldehyde), and 6-fold (acetate) compared with CuR photoelectrodes operating at a negative applied potential of −1.8 V (vs. reversible hydrogen electrode, RHE). Conversely, the CuR photoelectrodes exhibit a maximum HER rate of ∼86% at −1.8 V (vs. RHE), higher than those of the CuR/Ag (54%) and CuR/Ag-Pd (35%) photoelectrodes. The superior PEC–CO2RR performance of CuR/Ag-Pd photoelectrodes is attributable to the higher electrochemical active surface area (6.7 mF/cm2) and faster charge transfer rate at the electrode/electrolyte interface owing to the presence of cocatalysts. In addition, the CuR/Ag-Pd photoelectrodes exhibit remarkable long-term stability retaining 70% of the initial performance even after a relatively more negative applied potential at −1.2 V. A comprehensive investigation into the changes in surface morphology, crystal structure, and elemental composition after PEC–CO2RR confirms the higher stability of CuR/Ag-Pd photoelectrodes. Thus, this work provides novel perceptions into the development of Cu-based heterojunction photoelectrodes integrated with Ag/Pd cocatalysts for improving the selectivity of C2+ products.

Original languageEnglish
Article number112442
JournalJournal of Environmental Chemical Engineering
Volume12
Issue number2
DOIs
Publication statusPublished - 2024 Apr

Bibliographical note

Publisher Copyright:
© 2024 Elsevier Ltd

Keywords

  • C product
  • CO reduction
  • Cu/CuO/CuO/Ag-Pd photoelectrode
  • Photoelectrochemical
  • Propanol formation

ASJC Scopus subject areas

  • Chemical Engineering (miscellaneous)
  • Waste Management and Disposal
  • Pollution
  • Process Chemistry and Technology

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