Flowable capacitive cathode for efficiency carbon dioxide reduction in photoelectrochemical cell

ABSTRACT

Photoelectrochemical (PEC) Cell reduction carbon dioxide (CO₂) is a promising avenue for converting CO₂ into valuable products. In this work, a flowable electrode with a rotating impeller collector was proposed to enhance the efficiency of the carbon dioxide reduction reaction (CO₂RR) in a photoelectrochemical system. Titanium carbide (Ti₃C₂), with its capacitive properties, serves as a catalyst and is fluidized in the cathode chamber. The frequent contact between the Ti₃C₂ catalysts and the rotating impeller collector extends the catalytic reaction throughout the catholyte and enhances the efficiency of CO₂RR. The feasibility of the design was verified through suspension characterization, CO₂ diffusion concentration measurement, capacitance characterization, and experimental factor analysis. The PEC with a flow electrode exhibits CO and CH₄ production rates of 1.64 μmol g⁻¹h ⁻¹and 9.62 μmol g⁻¹h⁻¹, respectively, which are 3.5 and 7.2 times higher than those of the fixed cathode. The Faradaic efficiency for CH₄ reaches 92.4%. Moreover, the collision probability of the flow electrode is 17.7%, which is significantly higher than that of the conventional bubbling fluidized electrode. In addition, the capacitive properties of Ti₃C₂ particles favor the continuous CO₂RR under open circuit conditions, which was verified by an EDS test of Na⁺. Finally, the operational mechanism of the PEC system is described.

KEYWORDS:

• Flowable cathode
• impeller collector
• capacitive
• CO₂ reduction
• photoelectrochemical

Highlights

• A novel rotating impeller collector was proposed to support the PEC system.

• Ti₃C₂, which has great capacitive properties, was introduced as a fluidized cathode.

• The PEC system displayed excellent suspension properties for Ti₃C₂ particles.

• Yields of CO and CH₄ that were 3.5 and 7.2 times higher than those of a fixed cathode were obtained.

Acknowledgements

We acknowledgments the Science and Technology Department Project of Henan Province (222102320109).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the Science and Technology Department Project of Henan Province [222102320109].

Notes on contributors

Jun Zhang

Jun Zhang is an associate professor at Zhengzhou University of Light Industry, mainly engaged in research on fuel cells.

Ankang Fang

Ankang Fang is a master's student at Zhengzhou University of Light Industry, involved in research on photocatalytic carbon dioxide reduction.

Jili Zheng

Jili Zheng is a lecturer at Zhengzhou University of Light Industry, specializing in research on fuel cells.

Penglin Yang

Penglin Yang is a master's student at Zhengzhou University of Light Industry, focusing on research on photoelectric catalysis for the degradation of pollutants.

Shuai Lv

Shuai Lv is a master's student at Zhengzhou University of Light Industry, engaged in research on photocatalytic carbon dioxide reduction.

Chuanxiao Cheng

Chuanxiao Cheng is an associate professor at Zhengzhou University of Light Industry, conducting research on hydrate energy storage.

Peiyuan Xu

Peiyuan Xu is a professor at Zhengzhou University of Light Industry, primarily involved in research on chemical process and equipment.

Shuang Cao

Shuang Cao is a lecturer at Zhengzhou University of Light Industry, specializing in research on energy system optimization and design.