Photocatalytic CO ₂ Conversion Driven by UV Light Above 300 nm Using Ammonia as an Electron Donor
- 1Department of Chemical Science and Engineering, Graduate School of Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto, Kyoto, Japan, 615-8510
- 2Fukui Institute for Fundamental Chemistry, Kyoto University, Takano Nishibirakicho 34-4, Sakyo-ku, Kyoto, Japan, 606-8103
Abstract
Efficient utilisation of solar UV light ( λ > 300 nm) is essential for practical photocatalytic CO 2 conversion. However, in conventional systems using water as an electron donor, slow water oxidation kinetics present a critical bottleneck that severely limits the CO production rate. Here, we demonstrate an efficient CO 2 conversion system that overcomes this kinetic limitation by employing ammonia as an alternative electron donor over Mg-doped SrTiO 3 loaded with Ag and Fe as dualcocatalysts (Ag–Fe/Mg–SrTiO 3 ). Under UV irradiation ( λ > 300 nm), the optimised photocatalyst achieved a remarkable CO produc on rate exceeding 200 μmol h −1 . Mechanistic investigations revealed that the Fe cocatalyst played a crucial role in promoting ammonia oxidation, facilitating the rapid consumption of photogenerated holes, and significantly enhancing CO 2 conversion activity. Furthermore, nitrite (NO 2 − ) was successfully quantified as the primary oxidation product of ammonia, yielding a calculated e − / h + balance of approximately 1.2, validating the stoichiometric relationship of the reaction. This study offers a promising strategy for simultaneously achieving the upcycling of CO 2 and effective utilisation of ammonia as both an energy source and an electron donor.
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BibTeX
@misc{kajiwara2026photocatalytic,
title = {{Photocatalytic CO ₂ Conversion Driven by UV Light Above 300 nm Using Ammonia as an Electron Donor}},
author = {Koki Kajiwara and Shoji Iguchi and Shimpei Naniwa and Kentaro Teramura},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010290/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010290/v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Photocatalytic CO ₂ Conversion Driven by UV Light Above 300 nm Using Ammonia as an Electron Donor
AU - Koki Kajiwara
AU - Shoji Iguchi
AU - Shimpei Naniwa
AU - Kentaro Teramura
PY - 2026
DA - 2026/10/12
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010290/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010290/v1
AB - Efficient utilisation of solar UV light ( λ > 300 nm) is essential for practical photocatalytic CO 2 conversion. However, in conventional systems using water as an electron donor, slow water oxidation kinetics present a critical bottleneck that severely limits the CO production rate. Here, we demonstrate an efficient CO 2 conversion system that overcomes this kinetic limitation by employing ammonia as an alternative electron donor over Mg-doped SrTiO 3 loaded with Ag and Fe as dualcocatalysts (Ag–Fe/Mg–SrTiO 3 ). Under UV irradiation ( λ > 300 nm), the optimised photocatalyst achieved a remarkable CO produc on rate exceeding 200 μmol h −1 . Mechanistic investigations revealed that the Fe cocatalyst played a crucial role in promoting ammonia oxidation, facilitating the rapid consumption of photogenerated holes, and significantly enhancing CO 2 conversion activity. Furthermore, nitrite (NO 2 − ) was successfully quantified as the primary oxidation product of ammonia, yielding a calculated e − / h + balance of approximately 1.2, validating the stoichiometric relationship of the reaction. This study offers a promising strategy for simultaneously achieving the upcycling of CO 2 and effective utilisation of ammonia as both an energy source and an electron donor.
ER -