Electrochemical CO 2 reduction uses renewable electricity to convert CO 2 into value-added fuels and chemicals, offering a promising route for carbon recycling. However, most current studies rely on high-purity CO 2 feeds, while practical carbon sources such as industrial flue gas and air contain dilute CO 2 together with impurities including O 2 , SO x , and NO x . Low CO 2 concentrations limit mass transport and promote the competing hydrogen evolution reaction, while impurities may trigger side reactions or deactivate catalytic sites. A team of scientists has reviewed recent progress in the electrochemical capture and conversion of dilute CO 2 , outlining strategies to bring CO 2 electrolysis closer to practical carbon sources. Their work is published in the journal Industrial Chemistry & Materials on July 15, 2026.
“One of the key challenges is to maintain sufficient CO 2 availability at the active sites under dilute CO 2 while minimizing the effects of competing reactions and impurities,” explains Ying Wang, a professor at The Chinese University of Hong Kong.
The researchers highlight two main approaches for utilizing dilute CO 2 . The first is integrated CO 2 capture and conversion. In single electrolytic cell systems, captured carbon species are directly converted within the same device, while dual electrolytic cell systems separate CO 2 capture from electrochemical conversion, allowing the two processes to be optimized independently.
The second route is the direct electrolysis of dilute CO 2 , which avoids a separate capture step but faces greater challenges in CO 2 transport and impurity tolerance. Strategies such as porous catalyst structures, CO 2 -affinity functional groups, and wettability regulation can increase the local CO 2 concentration near active sites and stabilize the gas-liquid-solid reaction interface.
Impurities in realistic gas streams present an additional challenge. O 2 can compete for electrons through the oxygen reduction reaction, SO x may cause irreversible poisoning of catalytic sites, and NO x can undergo competing reduction reactions. Developing catalysts and interfaces that favor CO 2 transport and conversion while suppressing these unwanted pathways is therefore important for direct flue-gas electrolysis.
The review also emphasizes that catalyst development alone is not sufficient. Gas diffusion layers, flow-field design, pressure, temperature, humidity, and electrolyte composition all influence reactant transport, product selectivity, and long-term stability.
“Dilute CO 2 electrolysis is not simply a catalyst problem, but a system-level challenge,” says Professor Wang. “Catalyst design and electrolyzer engineering need to be considered together to achieve efficient and stable operation under realistic conditions.”
Looking ahead, the researchers identify several priorities, including multifunctional catalysts for CO 2 enrichment and impurity tolerance, a better understanding of catalyst deactivation under mixed contaminants, operando measurement of local CO 2 concentrations, and improved mass-transfer uniformity during electrolyzer scale-up. These advances could help enable selective, durable, and scalable electrochemical conversion of low-concentration CO 2 from practical carbon sources.
The research team includes Birou Huang, Renzhong Zhang, Qian Lu, Weixing Wu, Zhuohan Chen, and Ying Wang from The Chinese University of Hong Kong; and Pratahdeep Gogoi and Yuguang C. Li from the University at Buffalo, The State University of New York.
This research is funded by the Research Grants Council of the Hong Kong Special Administrative Region and the 1+1+1 CUHK-CUHK(SZ)-GDSTC Joint Collaboration Fund.
D OI Link:
https://doi.org/10.1039/d6im00201c
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Industrial Chemistry and Materials
Electrochemical low-concentration CO2 capture and conversion: from catalyst design to electrolyzer engineering
15-Jul-2026