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Electroreduction of carbon dioxide (CO2) to chemicals is a promising route to convert and utilize CO2 under atmospheric conditions. However, the relative poor reaction efficiency seriously hinders the practical applications of this route. In this work, flowerlike In2S3 assembled by nanoflakes was synthesized via ionothermal method and exhibited a high Faradaic efficiency (FE) of 86 % with excellent formate formation rate of 478 μmol h−1 cm−2 in ionic liquid (IL) electrolyte. Flowerlike structure can provide large electrochemically active surface area and enhance mass transfer rate. Additionally, density functional theory (DFT) calculations reveal that the origin of the improved performance can be attributed to the large adsorption energy of CO2* and OCHO* intermediate on the (440) facet which is the main exposed crystal facet of flowerlike In2S3.[f1] [ABSTRACT FROM AUTHOR]

Abstract: Electroreduction of carbon dioxide (CO2) into high value‐added products is a potential solution to a reduction in CO2 levels and its utilization. One major challenge is the lack of an efficient system that can highly selectively reduce CO2 into desirable products with low energy consumption. Ionic liquids (ILs) have been used as electrolytes for the electroreduction of CO2, and it has been proven that the CO2–cation complex results in a low‐energy pathway. In this work, an ionic microhabitat (IMH) has been built for CO2 electroreduction, and a novel anion‐functionalized IL, 1‐butyl‐3‐methylimidazolium 1,2,4triazolide ([Bmim][124Triz]), has been designed as the reaction medium. The results showed that the IMH played a key role in enhancing the performance of CO2 electroreduction, especially in dominating the product selectivity, which is recognized to be a great challenge in an electroreduction process. New insights into the role of the IMH in higher CO2 solubility, bending linear CO2 by forming the [124Triz]–CO2− adduct, and transferring activated CO2 into the cathode surface easily were revealed. The Faradaic efficiency for formic acid is as high as 95.2 %, with a current density reaching 24.5 mA cm−2. This work provides a promising way for the design of robust and highly efficient ILs for CO2 electroreduction. [ABSTRACT FROM AUTHOR]

Abstract: The increasing emission of carbon dioxide (CO2) caused by the unrestrained consumption of fossil fuels in recent hundreds of years, has caused global environmental and social problems. Meanwhile, CO2 is a cheap, abundant and renewable C1‐feedstock, which can be converted into alcohols, ethers, acids and other value‐added chemicals. Compared with the thermal reactions, electrochemical reduction of CO2 is more attractive because of its advantages by using the seasonal, geographical and intermittent energy (tide, wind and solar) under mild conditions. In recent years, taking ionic liquids (ILs) as electrolytes in the CO2 electrochemical reduction reaction has been paid much more attention due to the advantages of lowering the overpotential of CO2 electroreduction and improving the Faradaic efficiency. In this paper, we summarized the recent progresses of electrochemical reduction of CO2 in ILs electrolytes, and analyzed the reaction mechanism of CO2 reaction in the electrode‐electrolyte interface region by experimental and simulation methods. Finally, the research which needs to be highlighted in this area was proposed. [ABSTRACT FROM AUTHOR]

High CO FE and good stability in large-scale CO 2 ER device with 495 cm2 electrode area was realized by IL-based electrolytes [Display omitted] • An upscaling device of CO 2 ER with the biggest electrode area was established. • IL-based electrolytes were firstly used in upscaling device to boost CO 2 conversion. • The superior CO 2 ER performance of 83.9% CO FE with only 2% H 2 FE was achieved. • CO selectivity keeps good stability in IL systems on a continuous 10 hr running. Electric-driven CO 2 reduction to high value-added chemicals is a potential way to solve the carbon emissions. However, the current studies on CO 2 electroreduction (CO 2 ER) are mainly focused on design and preparation of novel electrocatalysts and electrolytes. The large-scale of CO 2 ER is puzzled in the serious hydrogen evolution reaction (HER) in aqueous electrolytes and inferior reaction stability in an enlarged CO 2 electrolyzer. Ionic liquids (ILs) as electrolytes have opened great opportunities for CO 2 ER due to their unique advantages. Herein, a large-scale CO 2 ER device containing an upscaling modified H-type flow cell using IL-based electrolytes (UHFC-IL) with the largest electrode active area of 495 cm2 was established for CO 2 ER studies. The influences of key operating parameters, such as compositions of IL-based electrolytes, electrolytes velocity, CO 2 gas flow rate and cell voltage on CO 2 ER performance were systematically investigated. A high CO 2 ER performance under the optimum operating conditions achieves 83.9% Faraday Efficiency (FE) for CO with a reaction current of 6.32 A, suppressing HER to only 2% FE. After 10 hr continuous operation, the CO selectivity in IL-based electrolytes is 51.3% higher than that in 0.1 M KHCO 3 aqueous electrolytes, which maintains excellent stability with a high CO generation rate of 1.7 L hr-1. In addition, the mechanism of CO 2 ER to CO boosted by IL-based electrolytes in UHFC-IL was proposed. This study provides experimental parameters and guidance for future research on the amplification process of CO 2 ER. [ABSTRACT FROM AUTHOR]