Electrochemical generation of syngas from water and carbon dioxide at industrially important rates

Abstract

A B S T R A C TThe electrochemical production of syngas would enable production of chemicals and transportation fuels from carbon dioxide, water and renewable energy, but a suitable process at the moment does not exist. In this paper we consider two options for syngas production: (i) CO 2 electrolysis to produce CO, water electrolysis to produce H 2 and then mixing the CO and H 2 to yield syngas; and (ii) the simultaneous coelectrolysis of CO 2 and H 2 O in a single electrolyzer. The results show that both processes can produce syngas at industrially important rates. In this paper we demonstrate CO 2 electrolysis at 100 mA/cm 2 , i.e., about 20 turnovers/s, and water electrolysis at 8 A/cm 2 at 2.0 V/cell, with about 1,600 turnovers/s. Both systems are stable for a thousand hours or more, i.e., millions of turnovers. We also demonstrate simultaneous CO and H 2 production in a single electrolyzer. These results demonstrate that syngas can be produced at industrially important rates via electrolysis.

CO2 reduction on gas-diffusion electrodes and why catalytic performance must be assessed at commercially-relevant conditions

“…Electrochemical CO 2 reactors using gas-diffusion layers have historically been used in diverse configurations, 13,[62][63][64] but range primarily from a Kenis-type reactor with a flowing catholyte 58,[65][66][67][68][69][70][71][72][73] (Fig. 2b), to membrane electrode assemblies 2,5,12,74,75 which directly combine a gasdiffusion layer, catalyst and ion exchange membrane into one unit ( Fig. 2c).…”

Syngas production from electrochemical reduction of CO2: current status and prospective implementation

“…al. 104 were also able to manipulate the H2/CO ratio from 0 to 103 thorugh different approaches, such as varying the cell potential, changing the Ni/Ag loading of their electrocatalyst from 1/0 to 4/1 and increasing the acidity of the electrolyte. They obtained 99.1 % of selectivity by using the EMIM-Cl ionic liquid at pH 6.6, which shifted to 0.9 % when the pH was reduced to 0.5.…”

Investigation of Electrocatalysts for Selective Reduction of CO2 to CO: Monitoring the Reaction Products by on line Mass Spectrometry and Gas Chromatography

“…However, it depends on several different experimental conditions such as applied potential, concentration of the reactants, electrolyte composition, temperature and electrocatalyst. 12 Metallic electrocatalysts have been commonly investigated in aqueous electrolyte such as gold, [13][14][15] copper, [16][17][18][19] tin, 20 silver 21,22 and nickel, 23 and they are classified according to their hydrogen evolution overpotentials and CO adsorption strength: 24 (i) metals such as Pb, Hg, In, Sn, Cd and Bi have high hydrogen overvoltages, negligible CO adsorption strength, high overpotentials for CO 2 to CO 2…”