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

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Electrochemical reduction of carbon dioxide (CO2) is a key technology for renewable energy storage and carbon utilization.
• Nickel (Ni) based catalysts show unique potential for producing longer-chain hydrocarbons via CO2 reduction.
• Detailed understanding of reaction parameters influencing Ni-catalyzed CO2 reduction is crucial for optimization.

Purpose of the Study:

• Investigate the impact of various parameters on hydrocarbon formation during electrochemical CO2 reduction on Ni.
• Elucidate the chain growth mechanism and identify key factors controlling selectivity.
• Compare the performance of CO2 reduction with carbon monoxide (CO) reduction on Ni catalysts.

Main Methods:

• Systematic variation of reaction temperature, CO2 concentration, applied potential, and electrolyte composition (cations and anions).
• Analysis of hydrocarbon products and catalyst deactivation (coke formation).
• Comparative studies using CO as a reactant instead of CO2.

Main Results:

• Increased temperature enhances catalytic activity but promotes coke formation, leading to catalyst deactivation.
• Applied potential and electrolyte composition significantly influence hydrocarbon selectivity and chain growth probability.
• Carbon monoxide (CO) reduction exhibits lower activity but higher chain growth probability compared to CO2 reduction.

Conclusions:

• Hydrogenation is identified as the likely rate-determining step in Ni-catalyzed hydrocarbon formation.
• The rate-determining step may involve either CO hydrogenation or hydrocarbon chain termination.
• These findings provide critical insights for optimizing Ni catalysts for efficient electrochemical CO2 reduction and hydrocarbon synthesis.