Rational integration of MoSe2 2 and BN with TiO2 2 to design nanoengineered ternary heterojunctions for sustainable hydrogen energy: Experimental evidences and theoretical anticipations

Ternary MoSe2-BN/TiO2 2-BN/TiO 2 and binary MoSe2-TiO2 2 - TiO 2 heterostructures are epitomized as Tortoise and Hare nano- catalysts to outline the synergism between bilayered MoSe2-BN 2-BN over pristine MoSe2 2 for their applicability in the photochemical and photo/-electrochemical water splitting operations. We report here the fabrication of MoSe2- 2- BN integrated TiO2 2 catalytic systems and ascertained experimental and theoretical investigations of MoSe2-BN/ 2-BN/ TiO2 2 and MoSe2-TiO2 2 - TiO 2 heterostructures that are directly proportional to their long-term applicability as the hydrogen evolution reaction (HER) catalysts. Optimized 5 wt% MoSe2-BN/TiO2 2-BN/TiO 2 and 7.5 wt% MoSe2-TiO2 2 - TiO 2 exhibited nearly 32-fold and 18-fold higher photochemical hydrogen evolution efficiency than bare TiO2 2 with 43.1% and 25.08% apparent quantum yield, respectively. Photo/-electrochemical studies verified the diversity of MoSe2-BN/TiO2 2-BN/TiO 2 and MoSe2-TiO2 2 - TiO 2 catalysts as applied potential values diminished drastically to attain benchmark 10 mA/cm2 2 current density for 5 wt % MoSe2-BN/TiO2 2-BN/TiO 2 (0.31 V) and 7.5 wt% MoSe2-TiO2 2 - TiO 2 (0.61 V). This work showcases the augmented HER activity of MoSe2-BN/TiO2 2-BN/TiO 2 due to the shielding of MoSe2 2 grain boundaries via BN-encapsulation that impeded the degradation of MoSe2 2 in aqueous condition ascribed to its wide band energy in UV region making it the advanced tunnel barrier.