Fig. 8: Online volatile products detection during HER.

Electrochemical mass spectrometry (EC-MS) measurements performed on c-MoS2 and a-MoS3-x during start-up/shut-down stress tests. Preconditioning: 100 CVs, 0 to −0.25 VRHE, 100 mV s−1. MS signal of (a) gaseous H2 (blue, m/z = 2) and (b) H2S (yellow, m/z = 34) plotted versus the stress test protocol.