Analysis of Products from Photoelectrochemical Reduction of 13CO2 by GaN-Si Based Tandem Photoelectrode

Takeyuki Sekimoto*, Hiroshi Hashiba, Shuichi Shinagawa, Yusuke Uetake, Masahiro Deguchi, Satoshi Yotsuhashi, Kazuhiro Ohkawa

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


Gallium nitride (GaN) has been shown to be a good photocatalyst for not only water splitting but also carbon dioxide (CO2) reduction. To verify the catalytic reaction involved in CO2 reduction, it is essential to confirm that the reaction products only come from dissolved CO2. Here, we report the results of 13CO2-labeling experiments on a GaN-Si based photoelectrochemical system for each reduction product. It was found that the 13C-based CO2 was almost completely converted to formic acid (HCOOH), methane, and ethylene when KCl was used as the electrolyte. In contrast, HCOOH from 12C was observed when KHCO3 electrolyte was used, meaning that HCO3- in the electrolyte partly contributed to CO2 reduction. The energy conversion efficiency and Faradaic efficiency of the respective reduction processes in the present system are also discussed.

Original languageEnglish (US)
Pages (from-to)13970-13975
Number of pages6
Issue number26
StatePublished - Jul 7 2016
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • General Energy
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films


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