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1. The mechanism for acetate formation in electrochemical CO ₍₂₎ reduction on Cu: selectivity with potential, pH, and nanostructuring

   https://doi.org/10.1039/d2ee01485h  

   Heenen, Hendrik H.; Shin, Haeun; Kastlunger, Georg; Overa, Sean; Gauthier, Joseph A.; Jiao, Feng; Chan, Karen (September 2022, Energy & Environmental Science)

   Nanostructured Cu catalysts have increased the selectivities and geometric activities for high value C–C coupled (C 2 ) products (ethylene, ethanol, and acetate) in the electrochemical CO (2) reduction reaction (CO (2) RR). The selectivity among the high-value C 2 products is also altered, where for instance the yield of acetate increases with alkalinity and is dependent on the catalyst morphology. The reaction mechanisms behind the selectivity towards acetate vs. other C 2 products remain controversial. In this work, we elucidate the reaction mechanism for acetate formation by using ab initio simulations, a coupled kinetic-transport model, and loading dependent experiments. We find that trends in acetate selectivity can be rationalized from variations in electrolyte pH and the local mass transport properties of the catalyst and not from changes in Cu's intrinsic activity. The selectivity mechanism originates from the transport of ketene, a stable (closed shell) intermediate, away from the catalyst surface into solution where it reacts to form acetate. While this type of mechanism has not yet been discussed in the CO (2) RR, variants of it may explain similar selectivity fluctuations observed for other stable intermediates like CO and acetaldehyde. Our proposed mechanism suggests that acetate selectivity increases with increasing pH, decreasing catalyst roughness and significantly varies with the applied potential. 

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2. Acid–Base Interaction Enhancing Oxygen Tolerance in Electrocatalytic Carbon Dioxide Reduction

   https://doi.org/10.1002/anie.202003093  

   Li, Pengsong; Lu, Xu; Wu, Zishan; Wu, Yueshen; Malpass‐Evans, Richard; McKeown, Neil B.; Sun, Xiaoming; Wang, Hailiang (April 2020, Angewandte Chemie International Edition)

   Abstract Hybrid electrodes with improved O₂tolerance and capability of CO₂conversion into liquid products in the presence of O₂are presented. Aniline molecules are introduced into the pore structure of a polymer of intrinsic microporosity to expand its gas separation functionality beyond pure physical sieving. The chemical interaction between the acidic CO₂molecule and the basic amino group of aniline renders enhanced CO₂separation from O₂. Loaded with a cobalt phthalocyanine‐based cathode catalyst, the hybrid electrode achieves a CO Faradaic efficiency of 71 % with 10 % O₂in the CO₂feed gas. The electrode can still produce CO at an O₂/CO₂ratio as high as 9:1. Switching to a Sn‐based catalyst, for the first time O₂‐tolerant CO₂electroreduction to liquid products is realized, generating formate with nearly 100 % selectivity and a current density of 56.7 mA cm⁻²in the presence of 5 % O₂. 

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3. Dielectric Barrier Discharge Reactors for Plasma‐Assisted CO ₂ and CH ₄ Conversion: A Comprehensive Review of Reactor Design, Performance, and Future Prospects

   https://doi.org/10.1002/ente.202401177  

   Ahasan, Md Robayet; Hossain, Md Monir; Wang, Ruigang (April 2025, Energy Technology)

   Dielectric barrier discharge (DBD) plasma is a promising technology for catalysis due to its low‐temperature operation, cost‐effectiveness, and silent operation. This review comprehensively analyzes the design and operational parameters of DBD plasma reactors for three key catalytic applications: CH₄conversion, CO₂splitting, and dry reforming of methane (DRM). While catalyst selection is crucial for achieving desired product selectivity, reactor design and reaction parameters such as discharge power, electrode gap, reactor length, frequency, dielectric material thickness, and feed gas flow rate, significantly influence discharge characteristics and reaction mechanisms. This review also explores the influence of less prominent factors, such as electrode shape and applied voltage waveforms. Additionally, this review addresses the challenges of DBD plasma catalysis, including heat loss, temperature effects on discharge characteristics, and strategies for enhancing overall efficiency. 

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4. Direct and continuous generation of pure acetic acid solutions via electrocatalytic carbon monoxide reduction

   https://doi.org/10.1073/pnas.2010868118  

   Zhu, Peng; Xia, Chuan; Liu, Chun-Yen; Jiang, Kun; Gao, Guanhui; Zhang, Xiao; Xia, Yang; Lei, Yongjiu; Alshareef, Husam N.; Senftle, Thomas P.; et al (December 2020, Proceedings of the National Academy of Sciences)

   null (Ed.)

   Electrochemical CO 2 or CO reduction to high-value C 2+ liquid fuels is desirable, but its practical application is challenged by impurities from cogenerated liquid products and solutes in liquid electrolytes, which necessitates cost- and energy-intensive downstream separation processes. By coupling rational designs in a Cu catalyst and porous solid electrolyte (PSE) reactor, here we demonstrate a direct and continuous generation of pure acetic acid solutions via electrochemical CO reduction. With optimized edge-to-surface ratio, the Cu nanocube catalyst presents an unprecedented acetate performance in neutral pH with other liquid products greatly suppressed, delivering a maximal acetate Faradaic efficiency of 43%, partial current of 200 mA⋅cm −2 , ultrahigh relative purity of up to 98 wt%, and excellent stability of over 150 h continuous operation. Density functional theory simulations reveal the role of stepped sites along the cube edge in promoting the acetate pathway. Additionally, a PSE layer, other than a conventional liquid electrolyte, was designed to separate cathode and anode for efficient ion conductions, while not introducing any impurity ions into generated liquid fuels. Pure acetic acid solutions, with concentrations up to 2 wt% (0.33 M), can be continuously produced by employing the acetate-selective Cu catalyst in our PSE reactor. 

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5. Cobalt telluride electrocatalyst for selective electroreduction of CO2 to value-added chemicals

   https://doi.org/10.1007/s40243-022-00211-6  

   Saxena, Apurv; Singh, Harish; Nath, Manashi (July 2022, Materials for Renewable and Sustainable Energy)

   Abstract Recent emphasis on carbon dioxide utilization has necessitated the exploration of different catalyst compositions other than copper-based systems that can significantly improve the activity and selectivity towards specific CO₂ reduction products at low applied potential. In this study, a binary CoTe has been reported as an efficient electrocatalyst for CO₂reduction in aqueous medium under ambient conditions at neutral pH. CoTe showed high Faradaic efficiency and selectivity of 86.83 and 75%, respectively, for acetic acid at very low potential of − 0.25 V vs RHE. More intriguingly, C1 products like formic acid was formed preferentially at slightly higher applied potential achieving high formation rate of 547.24 μmol cm⁻² h⁻¹ at − 1.1 V vs RHE. CoTe showed better CO2RR activity when compared with Co₃O₄, which can be attributed to the enhanced electrochemical activity of the catalytically active transition metal center as well as improved intermediate adsorption on the catalyst surface. While reduced anion electronegativity and improved lattice covalency in tellurides enhance the electrochemical activity of Co, high d-electron density improves the intermediate CO adsorption on the catalyst site leading to CO₂reduction at lower applied potential and high selectivity for C₂products. CoTe also shows stable CO2RR catalytic activity for 50 h and low Tafel slope (50.3 mV dec^–1) indicating faster reaction kinetics and robust functionality. Selective formation of value-added C₂products with low energy expense can make these catalysts potentially viable for integration with other CO₂capture technologies thereby, helping to close the carbon loop. 

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