Figure 7.

(a) Schematic diagram of the fabrication process of monolayer MoS₂ on nanoporous gold (MoS₂@NPG) hybrid materials by a nanoporous metal-based chemical vapor deposition (CVD) approach and schematic HER electrocatalysis. (b) Polarization curves and (c) the corresponding Tafel slopes of MoS₂@NPG, annealed NPG, and Pt. (d) Schematic illustration of the atomic layer deposition (ALD) TiO₂ coating on pristine MoS₂ and subsequent electrochemical activation. (e) High-resolution transmission electron microscope (HRTEM) images of pristine MoS₂ (bare), 50ALD(TiO₂)-MoS₂, and 50ALD(Act.)-MoS₂. (f) LSV curves of pristine MoS₂ and ALD(TiO₂)-MoS₂ samples with different cycles in a 0.5 M H₂SO₄ electrolyte. Note that the glassy carbon (GC) electrode is also tested as a reference. (g) iR-compensated LSV curves of pristine MoS₂ (activated) and ALD(Act.)-MoS₂ samples with different cycles, and (h) corresponding Tafel plots derived from (g). (i) Dependence of the Tafel slope and ALD cycle number before (square) and after (sphere) electrochemical activation. (a–c) have been reproduced with permission from Ref. 40. Copyright © 2014, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. (d–i) have been reproduced with permission from Ref. 41. Copyright © 2017, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.