The XPS analysis in Figure and S6 show that the peak positions of MoS 2 @NiFeCo-Mo(doped)-LDH are not altered during prolonged (photo)electrocatalysis. However, the surface composition of MoS 2 @NiFeCo-Mo(doped)-LDH does exhibit minor changes following extended electrocatalysis (Figure ). Figure also shows that both the HER and OER electrocatalytic performance remain rather unaffected by 500 CV cycles and 500 additional cycles under light irradiation. Under photoelectrocatalytic conditions, the performance of MoS 2 @NiFeCo-Mo(doped)-LDH is slightly decreased but we were not able to correlate this change in any structural or morphological changes. Altogether, the changes in the composition, structure, morphology, and (photo)electrocatalytic activity of MoS 2 @NiFeCo-Mo(doped)-LDH are modest, which underscores the high stability of the catalysts under electrocatalytic conditions.