Nickel as Electrocatalyst for CO₍₂₎ Reduction: Effect of Temperature, Potential, Partial Pressure, and Electrolyte Composition

Abstract

Electrochemical CO 2 reduction on Ni has recently been shown to have the unique ability to produce longer hydrocarbon chains in small but measurable amounts. However, the effects of the many parameters of this reaction remain to be studied in more detail. Here, we have investigated the effect of temperature, bulk CO 2 concentration, potential, the reactant, cations, and anions on the formation of hydrocarbons via a chain growth mechanism on Ni. We show that temperature increases the activity but also the formation of coke, which deactivates the catalyst. The selectivity and thus the chain growth probability is mainly affected by the potential and the electrolyte composition. Remarkably, CO reduction shows lower activity but a higher chain growth probability than CO 2 reduction. We conclude that hydrogenation is likely to be the rate-determining step and hypothesize that this could happen either by *CO hydrogenation or by termination of the hydrocarbon chain. These insights open the way to further development and optimization of Ni for electrochemical CO 2 reduction.

Electrocatalytic CO2 Reduction for Dynamic C1, C2, and C3+ Chemistry over Electrodeposited Zn on Cu and CuZn Mesh Supports

“…Nevertheless, the consistent observation of these productions has been discussed. Based on ASF plots, the production behavior appears similar to that in conventional FT synthesis, which produces long-chain alkanes and alkenes. − This process can be understood through the *CO and *CH 2 insertion mechanisms. On the electrode surface, the *H species were commonly abundant alongside *CO species, leading to the formation of *CH 2 species.…”

“…Previously, due to their low FE levels, these reaction pathways were often overlooked. However, they have recently been recognized as important in EC FT synthesis, − which is analogous to traditional FT synthesis. , …”