Fig. 5: Micro-electrochemical cell-based HER activity of a MoS2 nanograin film.
From: Engineering grain boundaries at the 2D limit for the hydrogen evolution reaction
a Schematic of the micro-electrochemical cell for HER measurements, where graphene serves as a vertical electron injector. b Photograph of the micro-electrochemical cell. c Optical images of the MoS2 nanograin device, consisting of a PMMA reaction window, a MoS2 nanograin film, a graphene supporting layer, and a SiO2/Si substrate from top to bottom. d–f Optical images of the MoS2 devices with a single GB (d), a single edge (e), and basal plane (f), respectively. In these devices, the HER process occurs at the exposed widows on the PMMA passivation film as indicated by the white arrow. g, h Polarization curves of the current density (g) and the corresponding Tafel plots (h) of the MoS2 devices. The window size is ~80 μm2 for each device.
