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.