Regulating surface structures for efficient electron transfer across h-BN/TiO₂/g-C₃N₄ photocatalyst for remarkably enhanced hydrogen evolution

This study reports significantly enhanced hydrogen production by conferring hierarchical porous TiO₂ and g-C₃N₄ over hexagonal boron nitride (h-BN). This design enables enhanced light absorption capacity, suppressed electron–hole recombination, noble metal-free catalysts and robustness. The synthesis of h-BN/TiO₂/g-C₃N₄ ternary composite by the deposition of g-C₃N₄ with morphological variation of Titanate entity (P25, 2D, and hierarchical porous TiO₂ (HPT) over the h-BN nanoparticles in a simple hydrothermal approach. Systematic study confirms that the regulated h-BN/TiO₂(HPT)/g-C₃N₄ ternary heterojunction nanocomposite exhibit remarkably enhanced rate of 2.02 mmolg⁻¹ h⁻¹ in comparison to 1.48 mmolg⁻¹ h⁻¹ and 0.98 mmolg⁻¹ h⁻¹ for h-BN/TiO₂(P25)/g-C₃N₄ and h-BN/TiO₂(2D)/g-C₃N₄ respectively. The hierarchical wormhole structured h-BN/TiO₂(HPT)/g-C₃N₄ exhibits the highest charge separation efficiency and enhanced photocatalytic hydrogen generation. The lifetime of the as-synthesized photocatalysts follows the trend similar to the hydrogen production as 25 ns > 11 ns > 1.5 ns for h-BN/TiO₂(HPT)/g-C₃N₄, h-BN/TiO₂(P25)/g-C₃N₄, and h-BN/TiO₂(2D)/g-C₃N₄, respectively. The electrochemical impedance spectra (EIS) reveals that the h-BN/TiO₂(HPT)/g-C₃N₄ exhibited better interactions between the surface of TiO₂ and h-BN/g-C₃N₄ and the corresponding flat-band potentials tends to be –0.82 eV, −0.55 eV, and -0.64 eV respectively, for titania modified ternary materials and possess adequate interfacial charge separation efficiency. The present observations unveiled that improved light-harvesting ability increased the photocatalytic activity surpassing the limitations of h-BN/TiO₂ heterostructure for better photocatalysis.