In addition to the low overpotential observed for MoS 2 @NiFeCo-LDH, this material also has a low Tafel slope 73 mV dec -1 as shown in Figure and S12. The concomitant Mo-doping and MoS 2 incorporation lead to an even lower Tafel slope: the MoS 2 @NiFeCo-Mo(doped)-LDH exhibits a very low slope of 57 mV dec -1 . This is much lower than observed for MoS 2 @NiFeCo-LDH and NiFeCo-Mo(doped)-LDH (126 mV dec -1 ). Both MoS 2 @NiFeCo-LDH and MoS 2 @NiFeCo-Mo(doped)-LDH have lower Tafel slopes than the commercial RuO 2 catalyst (94 mV dec -1 ) but Tafel slope of NiFeCo-LDH (39 mV dec -1 ) is even smaller. The Tafel slope analysis also indicates that the incorporation of MoS 2 QDs and Mo doping changes the RDS ; we ascribe the decreases in the Tafel slopes from ∼60 to ∼40 mV dec -1 to a change in the RDS from a chemical transformation following the first electron transfer to the second electron transfer step, that is from *O to *OOH formation (Equation 3 and 4). Under light irradiation, an extremely small Tafel slope is observed for both MoS 2 @NiFeCo-LDH (32 mV dec -1 ) and MoS 2 @NiFeCo-Mo(doped)-LDH (38 mV dec -1 ). Altogether, the alkaline OER activity of MoS 2 @NiFeCo-LDH surpasses that of most state-of-the-art OER catalysts, under both light irradiation and dark conditions, as shown in Table of the Supplementary Information.