Rigidity-Flexibility Integrated Porous Coordination Polymers via Lattice-Confined Adaptive Evolution for Efficient...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Adaptive catalytic systems are crucial for developing electrocatalysts with high activity and stability.
• Balancing structural robustness and dynamic adaptability in electrocatalysts remains a significant challenge.

Purpose of the Study:

• To design a self-adaptive electrocatalyst for enhanced ammonia electrosynthesis.
• To integrate a rigid framework with flexible coordination bonds within a porous coordination polymer (PCP).

Main Methods:

• Designed a rigid-flexible coupling copper pyrazole-based PCP (Cu-pyNDI) as a self-adaptive electrocatalyst.
• Utilized operando X-ray absorption spectroscopy (XAS) to investigate reaction mechanisms.
• Introduced iron doping to modulate copper's self-regulating behavior.

Main Results:

• Cu-pyNDI exhibited reversible local structural restructuring of copper sites during the reaction, forming lower-valence Cu species.
• Iron doping enhanced the formation of low-valence copper species with lower coordination numbers, facilitating *NO2 intermediate generation.
• Fe0.25Cu0.75-pyNDI achieved 93% Faradaic efficiency and 18847 µg h⁻¹ mgcat⁻¹ ammonia yield in neutral electrolytes.

Conclusions:

• The developed self-adaptive electrocatalyst demonstrates a promising strategy for efficient ammonia electrosynthesis.
• The rigid-flexible coupling design enhances both structural robustness and dynamic adaptability of the electrocatalyst.
• Iron doping effectively optimizes the active sites for improved electrocatalytic performance.