Fig. 6

Comparative XPS characterization of Fe/AlPMt in pristine and phosphate-adsorbed states. (a) Localized XPS survey scans of Fe/AlPMt pre- and post-phosphate exposure; (b) Post-adsorption P 2p spectral signature; (c, d) Fe 2p spectral comparisons before and after phosphate interaction; (e, f) O 1s spectral resolution under phosphate-free and phosphate-loaded conditions.