Nb₄N₃T_X MXene decorated Bi₂WO₆/NbSe₂ S-scheme heterojunction with improved optoelectronic and photoelectrochemical properties: Experimental and In-silico studies

Fabrication of a well-designed heterostructure is vital for attaining efficient charge-carrier separation. Herein, Nb₄N₃T_x MXene decorated Bi₂WO₆/NbSe₂ S-scheme heterojunction with enhanced interfacial charge transfer capabilities was designed via hydrothermal and ultrasonication synthetic routes. A well-anchored Nb₄N₃T_x and Bi₂WO₆ reticulated nanoflowers onto the surface of NbSe₂ nanorod confirmed successful heterojunction fabrication. The optical properties of the hierarchical heterostructure fitted an absorption edge from 430 to 540 nm. Dual transfer channels were realized through a Schottky-junction transfer path at the NbSe₂@Nb₄N₃T_x MXene, while the Bi₂WO₆/NbSe₂ interface depicted an S-scheme transfer mode. Ultimately, Bi₂WO₆/NbSe₂@Nb₄N₃T_x MXene S-scheme heterojunction achieved high charge-carrier separation and transport efficiency, with a charge-carrier density of 1.54 × 10³⁴ cm⁻³. Incorporation of density functional theory (DFT) prediction complemented the experimental observation. The density of states (DOS) revealed the electron migration route while the band structures confirmed the band gap energy of the materials.