Anthraquinone-2-Sulfonate as a Microbial Photosensitizer and Capacitor Drives Solar-to-N 2 O Production with a Quantum Efficiency of Almost Unity

Semiartificial photosynthesis shows great potential in solar energy conversion and environmental application. However, the rate-limiting step of photoelectron transfer at the biomaterial interface results in an unsatisfactory quantum yield (QY, typically lower than 3%). Here, an anthraquinone molecu...

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Bibliographic Details
Published in:Environmental science & technology 2022-04, Vol.56 (8), p.5161-5169
Main Authors: Chen, Man, Cai, Quanhua, Chen, Xiangyu, Huang, Shaofu, Feng, Qinyuan, Majima, Tetsuro, Zeng, Raymond Jianxiong, Zhou, Shungui
Format: Article
Language:English
Subjects:
Anthraquinones
Denitrification
Nitrates
Nitrous Oxide
Photosensitizing Agents
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Summary:Semiartificial photosynthesis shows great potential in solar energy conversion and environmental application. However, the rate-limiting step of photoelectron transfer at the biomaterial interface results in an unsatisfactory quantum yield (QY, typically lower than 3%). Here, an anthraquinone molecule, which has dual roles of microbial photosensitizer and capacitor, was demonstrated to negotiate the interface photoelectron transfer via decoupling the photochemical reaction with a microbial dark reaction. In a model system, anthraquinone-2-sulfonate (AQS)-photosensitized , a maximum QY of solar-to-nitrous oxide (N O) of 96.2% was achieved, which is the highest among the semiartificial photosynthesis systems. Moreover, the conversion of nitrate into N O was almost 100%, indicating the excellent selectivity in nitrate reduction. The capacitive property of AQS resulted in 82-89% of photoelectrons released at dark and enhanced 5.6-9.4 times the conversion of solar-to-N O. Kinetics investigation revealed a zero-order- and first-order- reaction kinetics of N O production in the dark (reductive AQS-mediated electron transfer) and under light (direct photoelectron transfer), respectively. This work is the first study to demonstrate the role of AQS in photosensitizing a microorganism and provides a simple and highly selective approach to produce N O from nitrate-polluted wastewater and a strategy for the efficient conversion of solar-to-chemical by a semiartificial photosynthesis system.
ISSN:0013-936X
1520-5851
DOI:10.1021/acs.est.1c08710