Unveiling the Interfacial Effects for Enhanced Hydrogen Evolution Reaction on MoS2/WTe2 Hybrid Structures. Issue 19 (8th April 2019) - Zhou, Yu
Abstract: Using the MoS2 ‐WTe2 heterostructure as a model system combined with electrochemical microreactors and density function theory calculations, it is shown that heterostructured contacts enhance the hydrogen evolution reaction (HER) activity of monolayer MoS2 . Two possible mechanisms are suggested to explain this enhancement: efficient charge injection through large‐area heterojunctions between MoS2 and WTe2 and effective screening of mirror charges due to the semimetallic nature of WTe2 . The dielectric screening effect is proven minor, probed by measuring the HER activity of monolayer MoS2 on various support substrates with dielectric constants ranging from 4 to 300. Thus, the enhanced HER is attributed to the increased charge injection into MoS2 through large‐area heterojunctions. Based on this understanding, a MoS2 /WTe2 hybrid catalyst is fabricated with an HER overpotential of −140 mV at 10 mA cm −2, a Tafel slope of 40 mV dec −1, and long stability. These results demonstrate the importance of interfacial design in transition metal dichalcogenide HER catalysts. The microreactor platform presents an unambiguous approach to probe interfacial effects in various electrocatalytic reactions. Abstract : Catalysis of the hydrogen evolution reaction at MoS2 /WTe2 heterostructures is investigated with electrochemical microreactors. This study carefully determines that efficient charge injection from WTe2 to MoS2 leads to improved catalytic performance. The insights gained from microreactors are applied to a real catalyst system through the synthesis of MoS2 /WTe2 hybrid nanostructures with enhanced catalytic performance.