A photoelectrochemical-thermoelectric device for semi-artificial CO2 fixation employing full solar spectrum utilization

Samuel J. Cobb, Chanon Pornrungroj, Virgil Andrei, Vivek M. Badiani, Lin Su, Rita R. Manuel, Inês A.C. Pereira, Erwin Reisner

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Abstract

Natural and most artificial photosynthesis systems utilize a pair of light absorbers to convert CO2 into sugar and fuels. However, much of the solar energy is lost as unabsorbed (mainly infrared [IR]) irradiation and thermalization heat, limiting efficiency. Here, we show that a thermoelectric (TE) generator can harvest this waste heat toward unassisted CO2 reduction with a water-oxidizing BiVO4 photoanode upon irradiation by concentrated sunlight. We employ the enzyme formate dehydrogenase (FDh) as a model catalyst to achieve selective CO2-to-formate conversion with minimal overpotential. The catalytic activity of the FDh cathode and BiVO4 photoanode benefits from solar heating, enabling the bias-free semi-artificial FDh-TE-BiVO4 device to attain a 97% faradic yield for formate production under 3-sun irradiation. This work demonstrates unassisted CO2 reduction coupled to water oxidation using only a single semiconductor light absorber through effective waste heat utilization, overcoming the challenges of (non-)complementary light absorption and IR losses in both natural and artificial photosynthesis.

Original languageEnglish
Article number100505
JournalDevice
DOIs
Publication statusAccepted/In press - 2024

Keywords

  • BiVO
  • continuum modelling
  • DTI-2: Explore
  • enzyme electrochemistry
  • heat management CO reduction
  • photoelectrocatalysis
  • photoelectrochemistry
  • solar fuels
  • solar thermal conversion
  • thermoelectric generator

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