Promoting CO₂ Dynamic Activation via Micro-Engineering Technology for Enhancing Electrochemical CO₂ Reduction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Optimizing isolated metal sites for electrocatalytic CO2 reduction (CO2 RR) is crucial but challenging.
• Controlling coordination structure and reaction environment is key to boosting catalytic activity.

Purpose of the Study:

• To develop a novel strategy for encapsulating isolated metal sites into hollow nano-reactors.
• To investigate the catalytic performance of these engineered sites for CO2 RR.
• To explore the potential of this strategy for other metal sites and energy applications.

Main Methods:

• Electrostatic induced self-assembly to create isolated Ni-C3N1 moieties within hollow nano-reactors (I-Ni SA/NHCRs).
• Electrocatalytic CO2 reduction reaction (CO2 RR) testing in a flow cell.
• COMSOL Multiphysics finite-element method and Density Functional Theory (DFT) calculations.

Main Results:

• I-Ni SA/NHCRs achieved a Faradaic efficiency (FE) of 94.91% for CO and a partial current density of -15.35 mA cm-2 at -0.80 V.
• Performance surpassed catalysts with Ni-C2N2 moieties or without a hollow structure.
• High FE of 98.41% at 100 mA cm-2 was achieved in a flow cell; a zinc-CO2 battery demonstrated a peak power density of 2.54 mW cm-2.

Conclusions:

• The hollow nano-reactor structure and Ni-C3N1 moiety enhance kinetics by enriching electrons and shifting the d-band center, accelerating CO2 adsorption and activation.
• The developed strategy is versatile, successfully enabling the design of encapsulated isolated iron and cobalt sites.
• The I-Ni SA/NHCRs show promise for integrated energy systems, as demonstrated by the functional zinc-CO2 battery.