Metal contents were quantified using energy dispersive X-ray fluorescence (EDXRF). Briefly, ~30 mg of the catalyst was loaded into a polypropylene sample holder (1 cm diameter) that was sealed with ultralene film. Samples were loaded into a spectrometer (Shimadzu, EDX-7000), whose sample chamber was purged with He (Airgas, Ultra-zero grade). Measurements were taken between 0 -30 keV (100 co-averaged scans), and the relative intensities of the element-specific fluorescence features were used to calculate the percent, by mass, of each element within the sample.