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Aqueous electrolytes used in CO2 electroreduction typically have a CO2 solubility of around 34 mM under ambient conditions, contributing to mass transfer limitations in the system. Non-aqueous electrolytes exhibit higher CO2 solubility (by 5–8-fold) and also provide possibilities to suppress the undesired hydrogen evolution reaction (HER). On the other hand, a proton donor is needed to produce many of the products commonly obtained with aqueous electrolytes. This work investigates the electrochemical CO2 reduction performance of copper in non-aqueous electrolytes based on dimethylformamide (DMF), n-methyl-2-pyrrolidone (NMP), and acetonitrile (ACN). The main objective is to analyze whether non-aqueous electrolytes are a viable alternative to aqueous electrolytes for hydrocarbon production. Additionally, the effects of aqueous/non-aqueous anolytes, membrane, and the selection of a potential window on the electrochemical CO2 reduction performance are addressed in this study. Experiments with pure DMF and NMP mainly produced oxalate with a faradaic efficiency (FE) reaching >80%; however, pure ACN mainly produced hydrogen and formate due to the presence of more residual water in the system. Addition of 5% (v/v) water to the non-aqueous electrolytes resulted in increased HER and formate production with negligible hydrocarbon production. Hence, we conclude that aqueous electrolytes remain a better choice for the production of hydrocarbons and alcohols on a copper electrode, while organic electrolytes based on DMF and NMP can be used to obtain a high selectivity toward oxalate and formate., Large Scale Energy Storage, ChemE/Transport Phenomena, Engineering Thermodynamics, ChemE/Product and Process Engineering

Nowadays, Sn-based electrocatalysts for the electrochemical CO2 reduction reaction (eCO2RR) toward formic acid have been reported to reach industrially relevant current densities and Faradaic efficiencies approaching 100%. However, electrocatalyst stability remains inadequate and appears to be a crucial piece to the puzzle, as lifetimes in the range of several thousands of hours should be reached for practical application and economic viability. Here, we provide insights into stability issues related to Sn-based electrocatalysts and electrolyzers for formic acid production. By determining the chemical and physical phenomena that occur during the electrochemical reduction reaction on the surface and bulk of Sn-based catalysts, we intend to elucidate the most common degradation mechanisms that impair long-term electrocatalytic activity of these catalysts. Moreover, highlighting the importance of correctly selected process conditions and an optimized reactor design allows us to unveil all necessary aspects for a stable Sn-based eCO2RR toward formic acid., Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Large Scale Energy Storage

SnO2-Based materials have attracted much attention in the electrochemical oxidation field due to their high electrocatalytic activity. However, efforts are still required to improve their physical and electrochemical properties. Here we employed a CO2 laser thermal process, as a substitute to conventional furnace heating, for the synthesis of two SnO2-based anodes-Ti/SnO2-Sb2O5 and Ti/SnO2-Sb-La2O3. Compared with anodes made using conventional heating, the laser-prepared anodes show a more compact surface and a change from hydrophilic to super-hydrophobic wetting properties. Energy-dispersive X-ray spectroscopy and X-ray diffraction data reveal the uniform distribution of Sn, Sb, and La, as well as the formation of the desired oxides, respectively. The oxidation state and chemical composition were confirmed by X-ray photoelectron spectroscopy. Notably, the laser-prepared anodes exhibit a positive shift in the oxygen evolution overpotential, especially for the Ti/SnO2-Sb-La2O3 anode, and a 2-fold reduction in the charge transfer resistance. The electrochemical degradation of 4-nitrophenol (4-NP) was investigated in aqueous solutions by UV-Vis spectra employing all anodes produced. The results showed that laser-prepared Ti/SnO2-Sb-La2O3 displays the highest degradation efficiency at the lowest energy consumption. Also, a mechanism for the 4-NP oxidation at the SnO2-based anodes under the current working conditions is proposed. Finally, the notable reduction in processing time and energy spent using laser heating makes it a feasible alternative to produce SnO2-based anodes. Their improved properties enhance the potential of these anodes to be applied in the electrochemical treatment of polluted waters., Large Scale Energy Storage

Nowadays, Sn-based electrocatalysts for the electrochemical CO2 reduction reaction (eCO2RR) toward formic acid have been reported to reach industrially relevant current densities and Faradaic efficiencies approaching 100%. However, electrocatalyst stability remains inadequate and appears to be a crucial piece to the puzzle, as lifetimes in the range of several thousands of hours should be reached for practical application and economic viability. Here, we provide insights into stability issues related to Sn-based electrocatalysts and electrolyzers for formic acid production. By determining the chemical and physical phenomena that occur during the electrochemical reduction reaction on the surface and bulk of Sn-based catalysts, we intend to elucidate the most common degradation mechanisms that impair long-term electrocatalytic activity of these catalysts. Moreover, highlighting the importance of correctly selected process conditions and an optimized reactor design allows us to unveil all necessary aspects for a stable Sn-based eCO2RR toward formic acid., Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Large Scale Energy Storage

SnO2-Based materials have attracted much attention in the electrochemical oxidation field due to their high electrocatalytic activity. However, efforts are still required to improve their physical and electrochemical properties. Here we employed a CO2 laser thermal process, as a substitute to conventional furnace heating, for the synthesis of two SnO2-based anodes-Ti/SnO2-Sb2O5 and Ti/SnO2-Sb-La2O3. Compared with anodes made using conventional heating, the laser-prepared anodes show a more compact surface and a change from hydrophilic to super-hydrophobic wetting properties. Energy-dispersive X-ray spectroscopy and X-ray diffraction data reveal the uniform distribution of Sn, Sb, and La, as well as the formation of the desired oxides, respectively. The oxidation state and chemical composition were confirmed by X-ray photoelectron spectroscopy. Notably, the laser-prepared anodes exhibit a positive shift in the oxygen evolution overpotential, especially for the Ti/SnO2-Sb-La2O3 anode, and a 2-fold reduction in the charge transfer resistance. The electrochemical degradation of 4-nitrophenol (4-NP) was investigated in aqueous solutions by UV-Vis spectra employing all anodes produced. The results showed that laser-prepared Ti/SnO2-Sb-La2O3 displays the highest degradation efficiency at the lowest energy consumption. Also, a mechanism for the 4-NP oxidation at the SnO2-based anodes under the current working conditions is proposed. Finally, the notable reduction in processing time and energy spent using laser heating makes it a feasible alternative to produce SnO2-based anodes. Their improved properties enhance the potential of these anodes to be applied in the electrochemical treatment of polluted waters., Large Scale Energy Storage

The electrochemical reduction of CO2 to fuels or commodity chemicals is a reaction of high interest for closing the anthropogenic carbon cycle. The role of the electrolyte is of particular interest, as the interplay between the electrocatalytic surface and the electrolyte plays an important role in determining the outcome of the CO2 reduction reaction. Therefore, insights on electrolyte effects on the electrochemical reduction of CO2 are pivotal in designing electrochemical devices that are able to efficiently and selectively convert CO2 into valuable products. Here, we provide an overview of recently obtained insights on electrolyte effects and we discuss how these insights can be used as design parameters for the construction of new electrocatalytic systems., Large Scale Energy Storage

The electrochemical reduction of CO2 to fuels or commodity chemicals is a reaction of high interest for closing the anthropogenic carbon cycle. The role of the electrolyte is of particular interest, as the interplay between the electrocatalytic surface and the electrolyte plays an important role in determining the outcome of the CO2 reduction reaction. Therefore, insights on electrolyte effects on the electrochemical reduction of CO2 are pivotal in designing electrochemical devices that are able to efficiently and selectively convert CO2 into valuable products. Here, we provide an overview of recently obtained insights on electrolyte effects and we discuss how these insights can be used as design parameters for the construction of new electrocatalytic systems., Large Scale Energy Storage