The peak at 172 cm -1 is a lattice vibration of the h-WO3 structure. It is worth noting that h-WO3 is always in a partially reduced state due to the presence of stabilizing positive ions in its hexagonal channels, which is confirmed by the XPS spectra showing W⁵⁺ (Figure ), as well as the presence of NH₄⁺ (Figure ). The surface morphology and elemental distribution of WO3, both in powder form and selfgrown on different substrates are examined using a Scanning Electron Microscope (SEM) combined with Energy-Dispersive X-ray Spectroscopy (EDX). The SEM images revealed distinct differences between the two morphologies of WO3 (Figure , S4, and S5). In high-magnification images, the powder form of WO3 exhibited agglomerated nanoparticles, forming irregularly shaped particles (Figure ). In contrast, images of the WO3 grown on the