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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. 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 (August 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 CO 2  reduction products at low applied potential. In this study, a binary CoTe has been reported as an efficient electrocatalyst for CO 2 reduction 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 Co 3 O 4 , 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 CO 2 reduction at lower applied potential and high selectivity for C 2 products. 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 C 2 products with low energy expense can make these catalysts potentially viable for integration with other CO 2 capture technologies thereby, helping to close the carbon loop. 

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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. 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 (March 2020, Angewandte Chemie International Edition)

   Hybrid electrodes with improved O2 tolerance and capability of CO2 conversion into liquid products in the presence of O2 are 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 CO2 molecule and the basic amino group of aniline renders enhanced CO2 separation from O2. Loaded with a cobalt phthalocyanine‐based cathode catalyst, the hybrid electrode achieves a CO Faradaic efficiency of 71 % with 10 % O2 in the CO2 feed gas. The electrode can still produce CO at an O2/CO2 ratio as high as 9:1. Switching to a Sn‐based catalyst, for the first time O2‐tolerant CO2 electroreduction to liquid products is realized, generating formate with nearly 100 % selectivity and a current density of 56.7 mA cm−2 in the presence of 5 % O2. 

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5. Pt3Mn/SiO2 + ZSM-5 Bifunctional Catalyst for Ethane Dehydroaromatization

   https://doi.org/10.3390/catal14060365  

   Jiang, Shan; Chang, Che-Wei; Swann, William A; Li, Christina W; Miller, Jeffrey T (June 2024, Catalysts)

   Ethane dehydroaromatization (EDA) is a potentially attractive process for converting ethane to valuable aromatics such as benzene, toluene, and xylene (BTX). In this study, a Pt3Mn/SiO2 + ZSM-5 bifunctional catalyst was used to investigate the effect of dehydrogenation and the Brønsted acid catalyst ratio, hydrogen partial pressure, and reaction temperature on the product distributions for EDA. Pt3Mn/SiO2 + ZSM-5 with a 1/1 weight ratio showed the highest ethane conversion rate and BTX formation rate. Ethylene is initially formed by dehydrogenation by the Pt3Mn catalyst, which undergoes secondary reactions on ZSM-5, forming C3+ reaction intermediates. The latter form final products of CH4 and BTX. At conversions from 15 to 30%, the BTX selectivities are 82–90%. For all bifunctional catalysts, the ethane conversion significantly exceeds the ethane–ethylene equilibrium conversion due to reaction to secondary products. Low H2 partial pressures did not significantly alter the product selectivity or conversion. However, higher H2 partial pressures resulted in increased methane and decreased BTX selectivity. The excess hydrogen saturated the olefin intermediates to form alkanes, which produced methane by monomolecular cracking on ZSM-5. With an increasing reaction temperature from 550 °C to 650 °C, the benzene selectivity increased, while the highest BTX selectivity was obtained at 600 to 650 °C. 

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