Towards the Electrochemical Conversion of CO₂ to Formic Acid at an Applicative Scale: Technical and Economic Analysis of Most Promising Routes

Abstract

In the last decade, the electrochemical conversion of CO 2 to formic acid, FA, using Sn-based cathodes, was widely investigated. In this work, the technical feasibility and economic viability of this process were evaluated considering the most promising electrochemical routes reported in the literature. Five case studies, based on the utilisation of gas diffusion electrode (GDE) technologies or high CO 2 pressures, were analysed. The cost for producing FA by the electrochemical route was compared with that of the conventional chemical route. Several scenarios were envisioned finding the target figures of merit, the potential bottlenecks (including low FA concentration, GDE cost and high energy consumption) of each technology and the challenges that need to be faced. It was shown that the performances of these processes are not still adequate from an economic point of view and the improvements that should be achieved were identified. To be suitable for the commercialisation, the process should reach simultaneously high current density, faradaic efficiency and actual FA concentration as well as good stability with time and a limited cost of electrodes. In addition, it was shown that the utilisation of the excess electric energy generated from renewable sources could significantly reduce the costs of the process.

Electron Localization and Lattice Strain Induced by Surface Lithium Doping Enable Ampere‐Level Electrosynthesis of Formate from CO2

“…To assess the potential value of the obtained high formate concentrations, a simplified techno-economic analysis (TEA) was conducted based on the previously reported methodology. [2,28,29] Combining the purification and concentration costs to the commercial grade formic acid (85 wt %), the total production cost of our system was calculated as % $169 per ton, which was substantially lower than other electrochemical CO 2 RR systems for producing formate (Table S7), and also comparable to the reported chemical route as $115--$190 per ton, [30] thus suggesting the attractive perspective of our catalytic system.…”

Matching emerging formic acid synthesis processes with application requirements

“…Enhancing the concentration to current standards represents a big share of the energy cost of the production process. 4 The diluted state of formic acid obtained through electrolysis often is cited as a shortcoming, and recommendations have been formulated stating that future research should aim at increasing the concentration of formic acid in the electrolysis product. 2,4 Achieving experimentally near 100% concentration recently has been reported.…”

“…4 The diluted state of formic acid obtained through electrolysis often is cited as a shortcoming, and recommendations have been formulated stating that future research should aim at increasing the concentration of formic acid in the electrolysis product. 2,4 Achieving experimentally near 100% concentration recently has been reported. 2 However, a trade-off is encountered between electrolysis performance and formic acid concentration.…”

“…These setups produce formate at concentrations typically lower than 10 wt%. 4 Formic acid is produced in electrolysers where no alkali salt solution is present, neither at the anode nor cathode. Examples are a PEM-electrolyser, where anode and cathode are both pressed to a proton exchange membrane, 45 and a three-compartment electrolyser.…”

Electrochemical Conversion of Co2 to Formic Acid Using a Sn Based Cathode: Combined Effect of Temperature and Pressure

“…Generally, CO 2 EC processes require mild conditions and its scale up stages are relatively easy. Moreover, CO 2 EC processes could store the excess electric energy from intermittent renewable sources, available at a low price, as chemical energy, without any additional fossil fuel-based electricity, thus reducing the process' costs [7]. According to several techno-economic analyses, the synthesis of FA, as well as the production of syngas (mixture CO and H 2 ), via CO 2 EC seem the most suitable processes at an industrial level [7].…”