An initial proof of concept needs to validate the viability of MOBO for the OER activity-stability optimization of Co-Mn-Sb-Sn-Ti oxides. To avoid resynthesis and testing in each new iteration, a complete data set was constructed first using inhouse HT capabilities. This step was taken as no open-source data sets exists that resembles this multiobjective optimization task with 5 elements as features and activity and stability as properties. A grid search approach was chosen, where 70 samples (25 at.% difference between each composition) were synthesized using the pipetting robot with subsequent annealing. The samples were then assessed toward their activity and stability for acidic OER in 0.1 M HNO3 using the automated scanning flow cell (SFC) developed in an earlier study. The testing protocol applied to each sample is shown in Figure . The activity was assessed through the OER overpotential (ηOER) reached during the first 1 mA cm -2 hold, whereas the stability is determined from the ηOER change (ΔηOER) after the accelerated stress test (AST). Characterizing stability via ΔηOER is a classical and relatively facile approach in electrocatalysis, which was the main reason for its adoption for the MOBO-driven screening. This method provides a comprehensive view of the performance deterioration over time. For deeper insights into material degradation, a more involved operando technique based on mass spectrometry was used in subsequent investigations within this study, offering a detailed understanding of the catalyst dissolution during electrochemical testing.