CO2-Assisted Solution-Phase Selective Assembly of 2D WS2-WO3•H2O and 1T-2H MoS2 to Desirable Complex Heterostructures

Precise control of the lateral and vertical integration of two-dimensional (2D) heterostructures is exciting for novel electronic and photovoltaic applications. Fabricating assemblies of high-quality heterostructures with desirable compositions and sequences is challenging. In this work, with the assistance of supercritical CO2 (SC CO2), we successfully prepared the complex heterostructures of WS2-WO3H2O/1T-2H MoS2 with selective stacking assembly. Thanks to the unique properties of SC CO2, which can help to construct a unique solvent system where the hydrophilic or hydrophobic structure for the 2D layer heterostructure can be chosen, 2H-WS2/2H-MoS2 assemblies are formed efficiently as the preferred van der Waals heterojunctions. A superior photoelectrochemical activity toward hydrogen evolution based on such the quaternary heterostructures is achieved due to their strong interlayer electronic coupling as well as the increased conductivity and active sites in the hetero-structures.