| ¹⁹F NMR (428 ppm HFBA) | δ approximately −80.5 (terminal –CF₃), −118 and −127.1 (different –CF₂ environments in the perfluorinated carbon chain) |
|---|---|
| ¹⁹F NMR (10.7 ppm HFBA), before treatment | Three characteristic –CF₃ and –CF₂ resonances |
| ¹⁹F NMR (10.7 ppm HFBA), after 100 min with 3 h Pt-PS (800 ppm) and H₂O₂ (5 % v/v), 130 rpm, room temperature | A notable decline in the intensity of all fluorine resonances was observed |
| ¹⁹F NMR reporting qualifier | The (¹⁹F) NMR spectra showed a considerable decrease in the characteristic (CF₃) and (CF₂) signals of HFBA after 100 min of treatment, indicating a reduction in the HFBA concentration in the analyzed solution. However, this decrease alone does not confirm C–F bond cleavage or defluorination. Further analysis of fluoride release and fluorinated transformation products is required to confirm defluorination and establish the degradation pathway |
| UV–vis monitoring (HFBA; Pt/PS 400 ppm; H₂O₂ 5 vol.%; 25 mL; 130 rpm; room temperature), 10 min intervals | The characteristic UV absorption peak of HFBA was observed in the wavelength range of 220–243 nm. During the catalytic degradation process, the absorbance of HFBA at 243 nm gradually decreased. The temporal evolution of the spectrum showed a slow decline in the characteristic absorption peaks of HFBA |
Faizan Khan, Manigandan Sabapathy. “From roughness to reactivity: platinum nano-patches on polymer particles for PFAS degradation and defluorination.” ChemRxiv (). https://doi.org/10.26434/chemrxiv.15007678/v1
The main paper refers to supporting information, but no separate supporting information file was found among the files available from the ChemRxiv record
| UV–vis (1–5 h) | Continuous absorbance at 215 nm for 1 h, a shift to 216 nm for 2 h, then a return to 215 nm over 3–5 h |
|---|---|
| Zeta potential (0.7 mL sample in 1 mM NaCl) | Shift from +46 ± 3 mV to −54 ± 1.5 to −59 ± 2.6 mV |
| XPS survey (after 3 h) | Pt 4f was detected; definite Pt 4f peaks at approximately 71–75 eV and distinct C 1s and O 1s peaks from the polystyrene matrix |
| FESEM (×70,000–×80,000, SEI, 10 kV), 1 h | The PS particle surfaces remain mostly smooth and exhibit no discernible Pt nanoparticle coverage |
| FESEM (×70,000–×80,000, SEI, 10 kV), 2 h | Small, distinct Pt nanoparticles sparsely dispersed over the PS surface begin to appear; the coating is highly uneven, with rough textures and aggregated clusters |
| FESEM (×70,000–×80,000, SEI, 10 kV), 3 h | The Pt/PS particles showed a smoother surface than the particles obtained after 2 h |
| FESEM (×70,000–×80,000, SEI, 10 kV), 4 and 5 h | As the reaction continued to 4 and 5 hours, coating homogeneity decreased, with irregular Pt patches and localized agglomerates reappearing on the PS surface |
| EDX, Pt content over time | 1 h: 0 %; 2 h: approximately 0.2 wt%; 3 h: 0.1 wt%; 4 and 5 h: approximately 0.1 wt% |
| AFM (3 h) | Uniform distribution of platinum nanoparticles |
| HR-TEM (300 kV, 3 h) | Furthermore, the HR-TEM image in Figure 5 confirms the decoration of platinum nanoparticles on the surface of the polymer particles after the same reaction time |
| UV–vis/Tauc plot, apparent band gap over 1–5 h | A slight decrease was generally observed as the coating duration increased from 1 to 5 h |
| UV–vis/Tauc plot reporting qualifier | The apparent band gap obtained from the optical measurements does not, by itself, establish the positions of the conduction and valence bands or confirm photo-induced electron–hole generation |