The effect of flue gas contaminants on the CO2 electroreduction to formic acid

System Design Considerations for Enhancing Electroproduction of Formate from Simulated Flue Gas

“…We believe that the high coverage of SO 2 adsorbates or the sulfide-rich surface may hinder NO adsorption. Further examination of the adsorbed species should be conducted using surface-sensitive techniques such as in situ Raman spectroscopy in the future to explain this phenomenon. , We also note here that CO 2 RR under real flue gas conditions contains other impurities such as O 2 and particular matter, requesting further examination on their effects on CO 2 RR …”

Comparative Technoeconomic Analysis of Pathways for Electrochemical Reduction of CO2 with Methanol to Produce Methyl Formate

“…The standard flue gas composition was taken as 81% N 2 , 15% CO 2 , and 4% O 2 on a molar basis. 34 While typical flue gas contains additional trace contaminants such as NO x and SO x (typically <100 ppm), Hg, and particulate matter, these components were neglected for the present analysis on the assumption that they are effectively removed during carbon capture in Systems 1, 3, and 4 or that the electrolysis technology is durable and resistant to their presence in System 2. 31 Also, for System 2 utilizing direct electroreduction of flue gas, experimental data for a Pbcatalyzed CO 2 conversion in methanol to methyl formate showed consistent or even improved electrolysis performance in the presence of 4% O 2 , which was attributed to beneficial catalytic effects of maintaining the cathode surface oxide.…”

“…The source of the CO 2 feedstock was assumed to be the post-combustion gaseous output from a pulverized coal-fired power plant. The standard flue gas composition was taken as 81% N 2 , 15% CO 2 , and 4% O 2 on a molar basis . While typical flue gas contains additional trace contaminants such as NO x and SO x (typically <100 ppm), Hg, and particulate matter, these components were neglected for the present analysis on the assumption that they are effectively removed during carbon capture in Systems 1, 3, and 4 or that the electrolysis technology is durable and resistant to their presence in System 2 .…”

Impurity Tolerance of Unsaturated Ni-N-C Active Sites for Practical Electrochemical CO2 Reduction

“…While concentration of CO 2 through removal of impurities may be employed, at costs of around US$30–190 t CO 2 –1 to achieve 99.9% purity, direct electrochemical reduction of the flue gas would circumvent the need for carbon capture and thereby significantly reduce the capital and operating costs of the process . Typical components of flue gas include 2–10% O 2 , ∼500 ppm of SO x (mainly SO 2 ), ∼500 ppm of NO x (mainly NO), and trace-level impurities such as volatile organic compounds (VOCs) and HCN. , In general, impurities may affect the kinetics and selectivity of reactions through several pathways, such as (i) poisoning, where contaminants adsorb to the active sites of the catalyst, causing surface modification and eventual deactivation, (ii) preventing reactant access to active sites and hindering product diffusion, and (iii) introducing a competing reaction pathway that diverts current toward a more thermodynamically favorable product, such as the oxygen reduction (ORR) or reduction of SO 2 and NO in place of the CO 2 RR. , …”

“…11,12 In general, impurities may affect the kinetics and selectivity of reactions through several pathways, such as (i) poisoning, where contaminants adsorb to the active sites of the catalyst, causing surface modification and eventual deactivation, (ii) preventing reactant access to active sites and hindering product diffusion, and (iii) introducing a competing reaction pathway that diverts current toward a more thermodynamically favorable product, such as the oxygen reduction (ORR) or reduction of SO 2 and NO in place of the CO 2 RR. 13,14 The number of studies investigating the effects of gaseous impurities, including SO x and NO x , on the CO 2 RR with metalbased catalysts such as Sn, Cu, and Ag is limited. Nevertheless, it is known that the presence of SO x and NO x reduces the Faradaic efficiency (FE) of the CO 2 RR via adsorption to the metal surface, while the presence of O 2 causes significant charge diversion toward the ORR.…”