Electrocatalysis for carbon dioxide conversion into methanol.

Electrochemical reduction of CO2 has been pointed out as an interesting strategy to convert CO2 into useful chemicals. In addition, coupling CO2 electroreduction with renewable energies would allow storing electricity from intermittent renewable sources such as wind or solar power. In this work, an easy and fast method is adapted for the synthesis of pure and carbon supported Sn nanoparticles. The resulting nanoparticles have been characterized by transmission electron microscopy and their electrocatalytic properties towards CO2 reduction evaluated by cyclic voltammetry. Carbon supported Sn nanoparticles have been subsequently used to prepare Gas Diffusion Electrodes (Sn/C-GDEs). The electrodes have been characterized by scanning electron microscopy and also by cyclic voltammetry. 2Finally, the electrodes were tested on a continuous and single pass CO2 electroreduction filter-press type cell system in aqueous solution, to obtain formate at ambient pressure and temperature. These Sn/C-GDEs allow working at high current densities with low catholyte flow. Thus, for instance, at 150 mA cm -2 , a 70 % Faradaic Efficiency (FE) was obtained with a formate concentration of 2.5 g L -1 . Interestingly, by increasing the current density to 200 mA cm -2 and decreasing the flow rate, a concentration over 16 g L -1 was reached.Despite the high concentrations obtained, further research is still required to keep high FE operating at high current densities.

Irabien Broader contextClimate change mitigation and transition to energy systems less dependent on fossil fuels are great challenges in the 21 st century. Converting carbon dioxide into useful products (the so-called Carbon Capture and Utilisation, CCU) is an attractive strategy that can complement Carbon Capture and Storage (CCS). Particularly, the CO 2 valorisation by electrochemical routes is receiving increasing attention as a way to obtain chemicals with added-value and as a promising option to chemically store renewable energy from intermittent sources like solar or wind, thus reducing our reliance on fossil fuels. On the other hand, ionic liquids (ILs) are a family of compounds with unique properties that have led to their consideration as interesting alternative, more effective solvents in many applications, including in electrochemistry. Therefore, the growing interest in the electrochemical valorisation of CO 2 has resulted in different innovative attempts, including the use of ILs in order to improve the performance of these electrochemical approaches. This review aims to specifically address the use of ILs in the electrochemical process of CO 2 valorisation, offering a complete overview of the state-of-the-art to both inform readers and encourage further research efforts in this challenging field. Abstract 11The development of electrochemical processes for using captured CO 2 in the production 12 of valuable compounds appears as an attractive alternative to recycle CO 2 and, at the 13 same time, to store electricity from intermittent renewable sources. Among the different 14 innovative attempts that are being investigated to improve these processes, the 15 application of ionic liquids (ILs) has received a growing attention in recent years. This 16 paper presents a unified discussion of the significant work that involves the utilisation 17 of ILs for the valorisation of CO 2 by means of electrochemical routes. We discuss 18 studies in which CO 2 is used as one of the reactants to electrosynthesise value-added 19 products, among which dimethyl carbonate has been the focus of particular attention in 20 the literature. Approaches based on the electrochemical reduction of CO 2 to convert it 21 into products without the use of other carbon-based reactants are also reviewed, 22 highlighting the remarkable improvements that the use of ILs has allowed in the CO 2 2 electroreduction to CO. The review emphasises on different aspects related with process 24 design, including the nature of ILs anions and cations that have been used, the working 25 conditions, the electrocatalytic materials, the electrode configurations, or the design of 26 electrochemical cells, as well as discussing the most relevant observations, results and 27 figures of merit that the participation of ILs has allowed to achieve in these processes. 28 Several conclusions are finally proposed to highlight crucial challenges and 29 recommendations for future research in this area.30 31 32 42to phase out fossil fuels in heat and power producti...

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