Enhancing hydrogen evolution on the basal plane of transition metal dichacolgenide van der Waals heterostructures

Recent years have seen a surge in the use of low-dimensional transition metal dichacolgenides,such as MoS_(2),as catalysts for the electrochemical hydrogen evolution reaction.In particular,sulfur vacancies in MoS_(2)can activate the inert basal plane,but that requires an unrealistically high defect concentration(~9%)to achieve optimal activity.In this work,we demonstrate by firstprinciples calculations that assembling van der Waals heterostructures can enhance the catalytic activity of MoS_(2)with low concentrations of sulfur vacancies.We integrate MoS_(2)with various two-dimensional nanostructures,including graphene,h-BN,phosphorene,transition metal dichacolgenides,MXenes,and their derivatives,aiming to fine-tune the free energy of atomic hydrogen adsorption.Remarkably,an optimal free energy can be achieved for a low sulfur vacancy concentration of~2.5%in the MoS_(2)/MXene-OH heterostructure,as well as high porosity and tunability.These results demonstrate the potential of combining two-dimensional van der Waals assembly with defect engineering for efficient hydrogen production.