Heterostructures of 2D Core/Shell Nanoplatelets with 2D MoS₂ as an Efficient Electrocatalyst for Hydrogen Evolution Reaction

Heterostructured materials are emerging to improve the performance of hydrogen evolution reaction (HER) catalysts by controlling the interfacial charge-transfer process. Here, we report the synthesis of two-dimensional (2D) CdSe/CdS core/shell nanoplatelets (NPLs) with a 2D MoS2 nanosheet heterostructured electrocatalyst for hydrogen generation. The phonon vibration modes E-2g(1) and A(1g) of pristine MoS2 are upshifted in the case of the heterostructure due to the structural changes induced by stacking or interfacial van der Waals interactions. All of the characteristic peaks of Mo 3d are shifted to lower binding energy in the heterostructure due to the accumulation of electron density around the Mo atom. A promising electrocatalytic activity with an onset overpotential of 171 mV and a Tafel slope of 122 mV dec(-1) has been obtained in 2D NPLs-based heterostructured electrocatalysts in acidic medium. Theoretical calculations reveal the creation of a sulfur defect during the HER on heterostructures, leading to excellent activity due to the optimum adsorption of the H* intermediate in the hydrogen-evolving reaction.