PI.050 DRIFT-FTIR Analysis of CO Adsorbed on Supported Metals: Probing Metal Single-Atom in Carbon Nitrides

Resumo

Carbon nitrides (C₃N₄) are promising semiconducting polymers widely used in energy conversion reactions through photocatalytic pathways, owing to their stable two-dimensional structure and good electronic properties. These materials provide excellent coordination sites for stabilizing isolated atoms, making them ideal for use as photocatalysts in single-atom catalysis. This study employed DRIFT-FTIR (Diffuse Reflectance Infrared Fourier Transform Infrared Spectroscopy) to analyze the adsorption of CO molecules on supported metals, specifically Ni-PHI, Fe-PHI e Pt-PHI prepared from Na-PHI, in order to understand the impact of different metal concentrations on the coordination mode. The experimental process involved heating the sample to 350°C using helium, introducing CO, and then purging it with helium. The resulting spectra exhibited distinct bands indicating chemisorbed CO. Lower wavenumbers (below 2100 cm^-1) suggested CO coordinated with multiple transition metals, especially in samples with high metal loading, implying cluster formation. Higher wavenumbers (above 2150 cm^-1) indicated uniquely coordinated CO, implying the presence of isolated metal atoms. Further investigations using different nickel concentrations are planned to validate these findings, potentially revolutionizing the characterization of single-atom catalysts.