Interactions of CO₂ Anion Radicals with Electrolyte Environments from First-Principles Simulations

Abstract

Successful transformation of carbon dioxide (CO 2 ) into value-added products is of great interest, as it contributes in part to the circular carbon economy. Understanding chemical interactions that stabilize crucial reaction intermediates of CO 2 is important, and in this contribution, we employ atom centered density matrix propagation (ADMP) molecular dynamics simulations to investigate interactions between CO 2 – anion radicals with surrounding solvent molecules and electrolyte cations in both aqueous and nonaqueous environments. We show how different cations and solvents affect the stability of the CO 2 – anion radical by examining its angle and distance to a coordinating cation in molecular dynamics simulations. We identify that the strength of CO 2 – interactions can be tailored through choosing an appropriate cation and solvent combination. We anticipate that this fundamental understanding of cation/solvent interactions can facilitate the optimization of a chemical pathway that results from selective stabilization of a crucial reaction intermediate.

Cation-induced changes in the inner- and outer-sphere mechanisms of electrocatalytic CO2 reduction

“…However, for the negative CO − 2 , this is rather surprising but can be understood by considering interactions between K + and CO − 2 as well as their solvation properties. The formation of solvated CO − 2 -K + complexes is thermodynamically favorable, [40] but both CO − 2 and K + interact strongly with water and have hydration enthalpies of -1.7 and -2.0 eV, respectively. [40] Thus, we expect that CO − 2 -K + complex formation has a substantial activation energy arising from the need to at least partially break the solvation shells around both CO − 2 and K + .…”

“…The formation of solvated CO − 2 -K + complexes is thermodynamically favorable, [40] but both CO − 2 and K + interact strongly with water and have hydration enthalpies of -1.7 and -2.0 eV, respectively. [40] Thus, we expect that CO − 2 -K + complex formation has a substantial activation energy arising from the need to at least partially break the solvation shells around both CO − 2 and K + . Table 1 furthermore shows that in the presence of K + , CO − 2 has a more elongated C-O bond and a smaller O-C-O angle compared to those in pure water.…”

Revisiting Electrocatalytic CO2 Reduction in Nonaqueous Media: Promoting CO2 Recycling in Organic Molecules by Controlling H2 Evolution

“…[ 112 ] Also, different cations and solvents can impact the CO 2 •− stability. [ 115 ] Understanding cation/solvent interactions can enable the selective stabilization of the intermediate. Cencer and co‐workers [ 115 ] hypothesize that electrostatic and covalent/noncovalent interactions aligned with solvent stabilization and cation binding directly influence the inner‐sphere solvation effects.…”

“…[ 115 ] Understanding cation/solvent interactions can enable the selective stabilization of the intermediate. Cencer and co‐workers [ 115 ] hypothesize that electrostatic and covalent/noncovalent interactions aligned with solvent stabilization and cation binding directly influence the inner‐sphere solvation effects. They showed by ab initio molecular dynamics simulations that different cations and solvents affect the stability of the radical anion intermediate, and the eCO 2 RR activity is correlated to the bulk solvation properties in DME and DMSO.…”

CO2 Electroreduction in Organic Aprotic Solvents: A Mini Review

“…In addition, CO 2 has a high solubility in organic solutions. Among them, the most studied are ionic liquids [19][20][21][22][23][24][25][26], methanol solutions [27][28][29], and organic aprotic solvents [30][31][32][33][34][35][36][37][38][39][40]. In recent years, there has also been engagement in the CO 2 electrochemical reduction process in molten salts [41][42][43][44][45][46].…”