Powders were affixed to the sample plate using copper tape. Measurements were performed using a custom built SPECS XPS instrument. Charge neutralization was invoked during the analyses using a beam of 2 eV electrons at a current of 20µA. S3.2 Spectra: All spectra were acquired using a photon energy of 1486.6 eV Al Kα, with analysis performed on electrons escaping in a direction normal to the sample surface. The pass energy for all core level scans was 20 eV and the pass energy for survey scans was 70 eV.