In Situ Electrochemical Activation of Atomic Layer Deposition Coated MoS2 Basal Planes for Efficient Hydrogen Evolution Reaction

Molybdenum disulfide (MoS 2 ), which is composed of active edge sites and a catalytically inert basal plane, is a promising catalyst to replace the state‐of‐the‐art Pt for electrochemically catalyzing hydrogen evolution reaction (HER). Because the basal plane consists of the majority of the MoS 2 bulk materials, activation of basal plane sites is an important challenge to further enhance HER performance. Here, an in situ electrochemical activation process of the MoS 2 basal planes by using the atomic layer deposition (ALD) technique to improve the HER performance of commercial bulk MoS 2 is first demonstrated. The ALD technique is used to form islands of titanium dioxide (TiO 2 ) on the surface of the MoS 2 basal plane. The coated TiO 2 on the MoS 2 surface (ALD(TiO 2 )‐MoS 2 ) is then leached out using an in situ electrochemical activation method, producing highly localized surface distortions on the MoS 2 basal plane. The MoS 2 catalysts with activated basal plane surfaces (ALD(Act.)‐MoS 2 ) have dramatically enhanced HER kinetics, resulting from more favorable hydrogen‐binding.