Fig. 9: S-numbers for long-term, high-current HER measurements.

Compilation of Mo S-numbers obtained during long-term H-cell measurements consisting of (a) constant HER operation (5 h, −100 mA cm−2; left column) and (b) start-up/shutdown HER intermittent operation alternating (5 h, −100 mA cm−2 to 0 V vs. RHE; right column). Labels: a-MoS3-x (pale blue), c-MoS2 (dark blue).