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Regulating the selectivity toward a target hydrocarbon product is still the focus of CO2electroreduction. Here, we discover that the original surface Cu species in Cu gas‐diffusion electrodes plays a more important role than the surface roughness, local pH, and facet in governing the selectivity toward C1or C2hydrocarbons. The selectivity toward C2H4progressively increases, while CH4decreases steadily upon lowering the Cu oxidation species fraction. At a relatively low electrodeposition voltage of 1.5 V, the Cu gas‐diffusion electrode with the highest Cuδ+/Cu0ratio favors the pathways of hydrogenation to form CH4with maximum Faradaic efficiency of 65.4% and partial current density of 228 mA cm−2at −0.83 V vs RHE. At 2.0 V, the Cu gas‐diffusion electrode with the lowest Cuδ+/Cu0ratio prefers C–C coupling to form C2+products with Faradaic efficiency topping 80.1% at −0.75 V vs RHE, where the Faradaic efficiency of C2H4accounts for 46.4% and the partial current density of C2H4achieves 279 mA cm−2. This work demonstrates that the selectivity from CH4to C2H4is switchable by tuning surface Cu species composition of Cu gas‐diffusion electrodes.
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Optimizing the Flow Electrooxidation of Glycerol Using Statistical Design of Experiments
Many studies have investigated the conversion of biomass derivatives to value-added products. However, the influence of different factors on the reaction outcomes of these often-complex systems is not well understood. Herein, a statistical design of experiments—specifically, response surface methodology—is applied to the glycerol electrooxidation reaction in a flow electrolyzer. Four operational variables (glycerol concentration, NaOH concentration, flow rate, and catalyst loading) were investigated for their effects on measurable responses of the electrochemical reaction: current density and Faradaic efficiency to a given product. Independent optimizations of current density and Faradaic efficiency, as well as simultaneous optimization of both, were investigated. Each optimization was evaluated using response surface coefficients to analyze sensitivity and simulated runs to visualize the parameter space. These evaluations revealed contradictions in operating conditions required to simultaneously maximize current density and Faradaic efficiency to C3products glycerate and lactate, leading to low current densities and Faradaic efficiencies. However, simultaneously maximizing current density and Faradaic efficiency to C1product formate led to high current densities and Faradaic efficiencies. These insights guide tuning GEOR production to maximize overall reactor performance. Furthermore, this study outlines a framework for experimental evaluation and optimization of other electrolysis chemistries.
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- PAR ID:
- 10515916
- Publisher / Repository:
- The Electrochemical Society
- Date Published:
- Journal Name:
- Journal of The Electrochemical Society
- Volume:
- 171
- Issue:
- 6
- ISSN:
- 0013-4651
- Format(s):
- Medium: X Size: Article No. 063506
- Size(s):
- Article No. 063506
- Sponsoring Org:
- National Science Foundation
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