Rational integration of MoSe₂ and BN with TiO₂ to design nanoengineered ternary heterojunctions for sustainable hydrogen energy: Experimental evidences and theoretical anticipations

Ternary MoSe₂-BN/TiO₂ and binary MoSe₂–TiO₂ heterostructures are epitomized as Tortoise and Hare nanocatalysts to outline the synergism between bilayered MoSe₂-BN over pristine MoSe₂ for their applicability in the photochemical and photo/-electrochemical water splitting operations. We report here the fabrication of MoSe₂-BN integrated TiO₂ catalytic systems and ascertained experimental and theoretical investigations of MoSe₂-BN/TiO₂ and MoSe₂–TiO₂ heterostructures that are directly proportional to their long-term applicability as the hydrogen evolution reaction (HER) catalysts. Optimized 5 wt% MoSe₂-BN/TiO₂ and 7.5 wt% MoSe₂–TiO₂ exhibited nearly 32-fold and 18-fold higher photochemical hydrogen evolution efficiency than bare TiO₂ with 43.1% and 25.08% apparent quantum yield, respectively. Photo/-electrochemical studies verified the diversity of MoSe₂-BN/TiO₂ and MoSe₂–TiO₂ catalysts as applied potential values diminished drastically to attain benchmark 10 mA/cm² current density for 5 wt % MoSe₂-BN/TiO₂ (0.31 V) and 7.5 wt% MoSe₂–TiO₂ (0.61 V). This work showcases the augmented HER activity of MoSe₂-BN/TiO₂ due to the shielding of MoSe₂ grain boundaries via BN-encapsulation that impeded the degradation of MoSe₂ in aqueous condition ascribed to its wide band energy in UV region making it the advanced tunnel barrier.