2D-2D Nanoheterostructure of an Exposed {001}-Facet CuO and MoS 2 Based Bifunctional Catalyst Showing Excellent Surface Chemistry and Conductivity for Cathodic CO 2 Reduction.

A novel CuO-MoS 2 based heterostructure catalyst model system is proposed where a CuO nanosheet with exposed {001} facet with proper termination is the active surface for the catalysis and a MoS 2 nanosheet is the supporting layer. Density functional theory (DFT) calculations were performed to validate the model. The MoS 2 bilayer forms a stable heterostructure with {001} faceted CuO with different terminations exposing oxygen and copper atoms (active sites) on the surface. The heterostructure active sites with a low oxidation state of the copper atoms and subsurface oxygen atoms provide a suitable chemical environment for the selective production of multicarbon products from CO 2 electrocatalytic reduction. Furthermore, our heterostructure model exhibits good electrical conductivity, efficient electron transport to active surface sites, and less interfacial resistance compared to similar heterostructure systems. Additionally, we propose a photoenhanced electrocatalysis mechanism due to the photoactive nature of MoS 2 . We suggest that the photogenerated carrier separation occurs because of the interface-induced dipole. Moreover, we utilized a machine learning model trained on a 2D DFT materials database to predict selected properties and compared them with the DFT results. Overall, our study provides insights into the structure-property relationship of a MoS 2 supported 2D CuO nanosheet based bifunctional catalyst and highlights the advantages of heterostructure formation with selective morphology and properly terminated surface in tuning the catalytic performance of nanocomposite materials.