Bench-scale electrochemical system for generation of CO and syn-gas

Abstract

A flow cell based, bench-scale electrochemical system for generation of synthesis-gas (syn-gas) is reported. Sensitivity to operating conditions such as CO 2 flow, current density, and elevated temperature are described. By increasing the temperature of the cell the kinetic overpotential for the reduction of CO 2 was lowered with the cathode voltage at 70 mA cm -2 decreased by 0.32 V and the overall cell voltage dropping by 1.57 V. This equates to an 18% increase in cell efficiency. By closely monitoring the products it was found that at room temperature and 70°C the primary products are CO and H 2 . By controlling the current density and the flow of CO 2 it was possible to control the H 2 :CO product ratio between 1:4 and 9:1. The reproducibility of performing experiments at elevated temperature and the ability to generate syn-gas for extended periods of time is also discussed.

Electrochemical CO₂ Reduction – A Critical View on Fundamentals, Materials and Applications

“…Reliable information on the CO 2 RR and OER reaction kinetics specifically for gas diffusion configurations are, however, rare in literature. [27][28][29] For the sake of simplicity we therefore estimate CO 2 RR and OER overpotentials from experimental data available for polycrystalline catalyst materials in aqueous reaction environments. For such considerations we assume that the particular catalyst performance does not alter when going from an Ta ble 2.…”

“…1C. Importantly, the CO/H 2 ratio can be readily tuned by changing cell voltage [27,29] and potentially by the right choice of the catalyst system. are used.…”

Silver Supported on Titania as an Active Catalyst for Electrochemical Carbon Dioxide Reduction

“…[12] With respect to conversion, most studies that focus on the electroreduction of CO 2 to CO report current densities in the range of 2-118 mA cm À2 under ambient conditions, and most of these studies use Ag as the cathode catalyst. [7] For example, Dufek et al [13] and Delacourt et al [14] reported partial current densities for CO (j CO ) of less than 60 mA cm À2 at À1. while the Ag loading was decreased by a factor of 20.…”

“…K 2 SO 4 (0.5 m), a widely used electrolyte in CO 2 reduction studies, [13] was used here. In a standard three-electrode cell, KOH would react with CO 2 to form carbonate/bicarbonate, which would, therefore, decrease the electrolyte pH significantly (from 13.58 to 9.96) and thus the amount of the active species, molecular CO 2 .…”

Efficient Solar‐Driven Synthesis, Carbon Capture, and Desalinization, STEP: Solar Thermal Electrochemical Production of Fuels, Metals, Bleach

“…[ 21 , 30 , 31 ] The electrically driven (nonsolar) electrolysis of dissolved carbon dioxide is under investigation at or near room temperature in aqueous, non-aqueous, and PEM media. [32][33][34][35][36][37][38][39][40][41] These are constrained by the thermodynamic and kinetic challenges associated with ambient temperature, endothermic processes, of a high electrolysis potential, large overpotential, low rate and low electrolysis effi ciency. High-temperature, solid-oxide electrolysis of carbon dioxide dates back to suggestions from the 1960s to use such cells to renew air for a space habitat, [42][43][44] and the sustainable rate of the solid oxide reduction of carbon dioxide is improving rapidly.…”