Direct Observation of Dynamic Bond Evolution in Single-Atom Pt/C₃ N₄ Catalysts

Area of Science:

• Heterogeneous catalysis
• Materials science
• Clean energy conversion

Background:

• Single-atom catalysts (SACs) show promise for energy applications.
• Understanding dynamic mechanisms in SACs is crucial but often overlooked.
• Previous studies focused on pre/post-reaction states, lacking dynamic insights.

Purpose of the Study:

• To directly observe charge transfer and bond evolution in a single-atom Pt/C₃N₄ catalyst during photocatalytic water splitting.
• To elucidate the dynamic mechanisms underlying SAC performance.
• To compare the behavior of SACs with metallic nanoparticle catalysts.

Main Methods:

• Synchronous illumination X-ray photoelectron spectroscopy (SI-XPS).
• Photocatalytic water splitting experiments.
• Characterization of single-atom Pt/C₃N₄ and metallic Pt/C₃N₄ catalysts.

Main Results:

• Direct observation of Pt-N bond cleavage and C=N bond reconstruction under light excitation in SACs.
• Formation of Pt⁰ species during photocatalysis in SACs.
• Significantly enhanced H₂ production (14.7 mmol h⁻¹ g⁻¹) for SACs compared to metallic Pt/C₃N₄ (0.74 mmol h⁻¹ g⁻¹).

Conclusions:

• Dynamic bond evolution and charge transfer are key mechanisms in SACs for water splitting.
• SACs exhibit superior catalytic activity compared to their metallic counterparts due to unique dynamic behaviors.
• SI-XPS is a powerful technique for probing dynamic processes in single-atom catalysis.