Scanning transmission X-ray microscopy (STXM) was established as a powerful technique in the late 1980s by pioneering work by the Stony Brook university group at NSLS-1 . Its capacity for discriminating fine chemistry and chemical coordination variations at nanoscale, distinguish STXM as a tool of choice for materials characterization . STXM uses Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy as its main contrast mechanism, which provides speciation and electronic structure information from heterogeneous, nanostructured samples. NEXAFS microscopy using a STXM is a particularly powerful tool for studies of the 3d transition metal oxides important in SWS .