Patchwork-Structured Heterointerface of 1T-WS 2 /a-WO 3 with Sustained Hydrogen Spillover as a Highly Efficient Hydrogen Evolution Reaction Electrocatalyst.

Using tungsten disulfide (WS 2 ) as a hydrogen evolution reaction (HER) electrocatalyst brought on several ways to surpass its intrinsic catalytic activity. This study introduces a nanodomain tungsten oxide (WO 3 ) interface to 1T-WS 2 , opening a new route for facilitating the transfer of a proton to active sites, thereby enhancing the HER performance. After H 2 S plasma sulfurization on the W layer to realize nanocrystalline 1T-WS 2 , subsequent O 2 plasma treatment led to the formation of amorphous WO 3 (a-WO 3 ), resulting in a patchwork-structured heterointerface of 1T-WS 2 /a-WO 3 (WSO). Addition of a hydrophilic interface (WO 3 ) facilitates the hydrogen spillover effect, which represents the transfer of absorbed protons from a-WO 3 to 1T-WS 2 . Moreover, the faster response of the cathodic current peak (proton insertion) in cyclic voltammetry is confirmed by the higher degree of oxidation. The rationale behind the faster proton insertion is that the introduced a-WO 3 works as a proton channel. As a result, WSO-1.2 (the ratio of 1T-WS 2 to a-WO 3 ) exhibits a remarkable HER activity in that 1T-WS 2 consumes more protons provided by the channel, showing an overpotential of 212 mV at 10 mA/cm 2 . Density functional theory calculations also show that the WO 3 phase gives higher binding energies for initial proton adsorption, while the 1T-WS 2 phase shows reduced HER overpotential. This improved catalytic performance demonstrates a novel strategy for water splitting to actively elicit the related reaction via efficient proton transport.