MXene Schottky Functionalized Z‑scheme Ternary Heterostructure for Enhanced Photocatalytic H₂O₂ Production and H₂ Evolution

The design and development of a multiheterostructure interface signifies a promising route to overcome the drawbacks of single-component and traditional heterostructured photocatalysts. Herein, a one-dimensional (1D)/two-dimensional (2D)/2D heterostructure, α-MnO₂@B/O-g-C₃N₄/d-Ti₃C₂, is constructed by a facile two-step synthesis method to ensure charge separation and is utilized for photocatalytic H₂O₂ production and H₂ evolution. The formation of the individual materials and nanohybrids as well as the 1D/2D/2D interfacial interaction is ascertained by X-ray diffraction, Raman, and electron microscopy studies, respectively. 5-MX/MBOCN shows optimum photocatalytic H₂O₂ production (2846.4 μmol h^–1 g^–1) with 10% ethanol and H₂ evolution (897.2 μmol h^–1), which is, respectively, 2.5 and 1.6 times higher than that of the binary MBOCN counterpart. The greater cathodic current density from linear sweep voltammetry, hindered charge recombination from electrochemical impedance spectroscopy and photoluminescence measurement, and better photodurability all systematically demonstrated the improved photocatalytic performance. The mechanistic investigation shows that in the ternary hybrid, electrons flow from MnO₂ to boron-doped g-C₃N₄ through a Z-scheme charge dynamics and then electrons flow to the d-MXene surface, which acts as a cocatalyst. The charge transfer dynamics is corroborated by time-resolved photoluminescence, cyclic voltametric analysis, trapping experiment, and ESR analysis. This work instigates the design and development of a high-efficiency cocatalyst-integrated Z-scheme photocatalyst with strong interfacial interaction and high redox ability for solar to chemical energy conversion.