A framework for understanding efficient diurnal CO2 reduction using Si and GaAs photocathodes

Kyra M.K. Yap, Sang Won Lee, Myles A. Steiner, Jaime E. Avilés Acosta, Dongkyun Kang, Donghwan Kim, Emily L. Warren, Adam C. Nielander, Thomas F. Jaramillo

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Integrated solar fuels and photoelectrochemical (PEC) CO2 reduction (CO2R) are promising pathways toward producing value-added chemicals from CO2. However, improvements are needed in activity and selectivity as well as in fundamental understanding of device behavior to engender wide deployment. We report two single-junction, integrated photocathodes for PEC CO2R based on TOPCon Si and GaAs substrates, which achieve −10 mA cm−2 at −0.33 V vs. RHE with 41% selectivity to C2+ products and at −0.03 V vs. RHE with 27% selectivity to C2+ products, respectively. We investigated the viability of a light-mediated strategy to direct selectivity in buried-junction PEC devices and confirmed that these devices could be optimized independently and described by the physics-based models of the individual components. Finally, we designed a framework to assess operational modes for PEC CO2R devices and demonstrated this framework under continuous galvanostatic control and variable illumination conditions.

Original languageEnglish
Article number100641
JournalChem Catalysis
Issue number6
Publication statusPublished - 2023 Jun 15

Bibliographical note

Publisher Copyright:
© 2023 Elsevier Inc.


  • CO reduction
  • GaAs
  • SDG7: Affordable and clean energy
  • catalysis
  • diurnal
  • electrocatalysis
  • electrochemistry
  • light
  • photoelectrochemistry
  • solar
  • solar fuels

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Physical and Theoretical Chemistry
  • Organic Chemistry


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