Spontaneous Solar Syngas Production Driven by Energetically Favorable Wastewater Microbial Anodes

University of California, Irvine - Department of Materials Science and Engineering; University of California, Irvine - Department of Physics and Astronomy; University of California, Irvine - Irvine Materials Research Institute (IMRI)

Zhiyong Jason Ren

Princeton University - Department of Civil and Environmental Engineering

Jing Gu

San Diego State University - Department of Chemistry and Biochemistry

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Abstract

The photoelectrochemical (PEC) CO₂ reduction to syngas is an attractive strategy for solar to fuel conversion, however, the high overpotential, inadequate selectivity, and high cost call for alternative solutions. Here we demonstrate a hybrid microbial photoelectrochemical (MPEC) system which contains a microbial anode capable of oxidizing free waste organics in wastewater and reducing the oxidation potential by 1.1 V, compared to abiotic water oxidation on PEC anode. Moreover, the MPEC employs a power management circuit (PMC) to enable several low-energy producing reactions operated in the same solution medium to conquer high-overpotential reactions. The nanowire silicon photocathode integrated with a selective single-atom Nickel catalyst (Si NW/Ni SA) achieved up to ~80% Faradaic efficiency for CO generation with a highly tunable CO:H₂ generation ratio (0.1 to 6.8). When the bioanode couple with the Si NW/Ni SA, up to 1.1 mA cm⁻² spontaneous photocurrent density can be accomplished for syngas generation.

Keywords: Microbial photoelectrochemical CO2 reduction, Wastewater treatment, Self-sustaining system, Syngas generation

Suggested Citation: Suggested Citation

Lu, Lu and Li, Zhida and Chen, Xi and Wang, Huan and Dai, Sheng and Pan, Xiaoqing and Ren, Zhiyong Jason and Gu, Jing, Spontaneous Solar Syngas Production Driven by Energetically Favorable Wastewater Microbial Anodes. Available at SSRN: https://ssrn.com/abstract=3575135 or http://dx.doi.org/10.2139/ssrn.3575135

This version of the paper has not been formally peer reviewed.