The spectral shape of the bulk component (red in Figure ) confirms substitutional Ti 4+ inside the hematite structure. Switching to spectro-ptychography is very handy at HERMES beamline. The standard 0D detector, a photomultiplier tube, is replaced with a 2D detector (sCMOS camera), without modifying the sample setup (see Methods section 4.4.3. and Supporting Information -IV). Spectro-ptychography data was recorded from the same region of interest (ROI) as the one used for STXM (Figure ). The R(G)B color-coded map was obtained measuring 21 energy points across the Ti L3 t2g (peak A in Figure and inset) transition, using SVD similarly to S-XPEEM and STXM. Compared to STXM, less spectral points can be measured due to the huge amount of generated data (e.g. more than 14 Go per X-rays energy point), difficult to analyze even using dedicated workstation equipped with multiple GPUs. We can estimate that surface clusters (blue) size span from ~10 nm to ~100 nm, considering the ptychographic reconstructed image pixel size of 8.5 nm (Figure ). We mention that STXM spectral components shown in Figure were extracted as a second iteration during the cross analysis between STXM and spectro-ptychography data. Indeed, spectroptychography allows to isolate a spatial region with pure "blue" component, associated to the surface clusters. Owing to NEXAFS strong chemical coordination sensitivity we can separate distinct spectral components arising from distinct spatial locations. As a result, the chemical coordination allows improving spatial resolution using spectro-ptychography (see also Figure ). Spectro-ptychography recovers both amplitude (absorption) and phase (dispersion) information (Figure ). Further analysis can be performed following the arguments used by Farmand et al. Such in-deep analysis of spectro-ptychography is however beyond the scope of this paper. Analytical STEM-EDX (Figure ) characterization performed on the same nanoparticles, confirms the presence of the Ti-rich area at the surface of the Ti-doped hematite particles.