The OER performance of the LDH electrocatalysts was evaluated in 1 M KOH solution under both light irradiation and dark conditions, and compared to the benchmark catalyst RuO 2 . As depicted in Figure , the hierarchical MoS 2 @NiFeCo-LDH nanostructure exhibits the best and remarkably high OER activity. Specifically, as shown in Figure -12 and Table , the OER overpotential of MoS 2 @NiFeCo-LDH at 10 mA cm -2 is only 195 mV which is significantly lower than observed in most prior studies and the benchmark RuO 2 catalyst, which shows an overpotential of 303 mV at the same current density. Under light illumination, the overpotential of MoS 2 @NiFeCo-LDH is further reduced from 195 mV to 156 mV at a current density of 10 mA cm -2 . In contrast, the effect of light illumination on other LDH catalysts is less pronounced; for example, MoS 2 @NiFeCo-Mo(doped)-LDH shows a marginal reduction in overpotential from 204 mV to 202 mV at a current density of 10 mA cm -2 . Figures clearly show that the MoS 2 QDs can significantly enhance the OER photoelectrocatalytic activity of the different LDHs but the effect varies depending on the underlying LDH matrix. Among the studied LDHs, MoS 2 @NiFeCo-LDH exhibits the best photo-electrocatalytic activity towards OER.