The OER performance of the Mn1-x-y-zSbxSnyTiz-O catalysts was evaluated using a customized SDC instrumentation in 1 M H2SO4 aqueous electrolyte saturated with bubbled 1 atm O2 gas. The 3-electrode cell includes a Pt counter electrode, Ag/AgCl reference electrode, Gamry G300 potentiostat, and custom LabVIEW software. The measured potentials were converted to the reversible hydrogen electrode (RHE) scale according to the Nernst equation. Two cyclic voltammograms (CVs) from 1.23 to 1.79 V vs RHE was performed at a sweep rate of 0.02 V s -1 , and in between two CVs, each catalyst was characterized by a 200 seconds chronoamperometry (CA) at 1.72 V vs RHE, where the current over 1 s at the duration of 20 s and final 200 s were averaged to represent the activity metric at the beginning and end of CA. The current at 1.79 V vs RHE from the initial and post CA CV measurement is also used to represent the activity metric of the catalyst. Table summarizes the 4 OER activity metrics obtained from 182 OER catalytic measurements. The geometric surface area of 0.02 cm 2 was used to convert current into current density in the SDC experiments.