Rational synthesis of dual-atom catalysts for optimized thermochemical CO₂ reduction

Area of Science:

• Materials Science
• Catalysis
• Chemical Engineering

Background:

• Dual-atom catalysts (DACs) offer superior atom utilization and synergistic effects but face challenges in high-temperature applications due to unstable active sites.
• Achieving structurally homogeneous and robust active sites is crucial for advancing DACs in thermocatalysis.

Purpose of the Study:

• To develop a scalable synthesis for a robust Cu-Ni dual-atom catalyst (CuNi-DAC) with a well-defined atomic configuration.
• To evaluate the catalytic performance and stability of CuNi-DAC under high-temperature reverse water-gas shift (RWGS) reaction conditions.

Main Methods:

• A coordinated bottom-up synthesis strategy was employed to create CuNi-DAC on nitrogen-doped carbon.
• Catalytic performance was assessed using the RWGS reaction, with characterizations including ex-situ and in-situ techniques.
• Theoretical calculations were integrated to elucidate reaction mechanisms and structure-property relationships.

Main Results:

• The synthesized CuNi-DAC exhibited a precise N₂Cu-N₂-NiN₂ configuration with each metal atom coordinated to four nitrogen atoms.
• CuNi-DAC achieved CO₂ conversion near thermodynamic equilibrium with >99% CO selectivity under RWGS conditions.
• The catalyst maintained structural integrity and high performance up to 600°C over multiple cycles, unlike single-atom catalysts (SACs) which deactivated due to sintering.

Conclusions:

• The d-d orbital coupling and electronic polarization between Cu and Ni centers enhance selective CO₂ reduction and mitigate sintering.
• The scalable synthesis and demonstrated high stability provide a viable pathway for designing next-generation dual-atom catalysts.
• CuNi-DAC represents a significant advancement in high-temperature thermocatalysis, offering enhanced efficiency and tailored activity.