Atomic Coordination Editing Achieves Ultraproductive Single-Atom Catalysts with Ultralow Loadings

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• Developing efficient noble-metal catalysts with ultralow loadings for industrial applications is challenging.
• Existing catalysts often face limitations due to scaling relations between activity and selectivity.

Purpose of the Study:

• To synthesize ppm-level loaded Iridium single-atom catalysts (SACs) for enhanced propane dehydrogenation (PDH).
• To overcome scaling-relation limitations and achieve industrial-grade performance.

Main Methods:

• Facile synthesis via H2IrCl6 impregnation on carbon followed by NH3 pyrolysis.
• Advanced characterizations (e.g., X-ray spectroscopy, electron microscopy) and density functional theory (DFT) calculations.
• Evaluation of PDH performance, including conversion, selectivity, and stability.

Main Results:

• Achieved ~33% propane conversion and ~92% propylene selectivity with Ir SACs.
• Demonstrated exceptional propylene time-space yield (14976 molC3H6 molIr-1 h-1) and ultralow deactivation (0.00191 h-1).
• Identified an Ir-O2N2 active motif formed by in situ N-substitution of Cl, crucial for catalysis and stability.

Conclusions:

• The developed Ir SACs exhibit superior PDH performance, outperforming Ir nanoparticles and other noble-metal catalysts.
• The NH3 pyrolysis method effectively creates a stable and highly active single-atom active site.
• This strategy offers a blueprint for designing atom-economical and industrially viable SACs.