The alkaline OER generally proceeds through four proton-electron transfer steps and three main intermediates, OH * , O * , and OOH * , as shown in Figure . We assume that the OER follows the adsorbate evolution mechanism (AEM) identified as the most active mechanism on NiFe-LDHs under electrode potential conditions relevant to OER. In this work, we quantify the OER performance using the concept of thermodynamic overpotential, which measures the electrode potential needed for making all the steps thermodynamically feasible as discussed in the methods section. Within this thermodynamic framework, the OER efficiency is determined by the elementary step having the most endergonic reaction energy, which is assigned as the potential-determining step (PDS). We carried out this analysis for a range of experimentally studied catalysts with varying metal ratios and at different active sites. The results in Figure and S28-33 show the main computational results for the various LDH heterostructure catalysts towards OER. Figure shows that the Fe and Co sites of the Ni 7 Fe 2 Co 1 electrode have the lowest thermodynamic OER overpotentials among the studied MoS 2 -NiFeCo-LDHs, which exhibited the best OER performance in the experiments.. Additionally, the formation of *O from *OH was identified as the PDS for all sites of the Ni 7 Fe 2 Co 1 LDH (Figure ). However, the comparison of Figures 5d and S28-33 shows that MoS 2 @NiFeCo does not have the lowest thermodynamic overpotential among the studied structures; instead, the NiFeCo-LDH (Figure ) structure was found to exhibit significantly lower thermodynamic overpotentials than other catalysts. This computational finding is, however, not consistent with the experimental results in Figures , which show that MoS 2 @NiFeCo is a better OER catalyst than NiFeCo.