Layered borophene maximizes the active sites in in-situ synthesized Bi2MoO6/BiVO4 heterostructures towards high-performance supercapacitors and efficient photocatalysts

Abstract

Bi₂MoO₆ and BiVO₄ materials are promising for supercapacitors and photocatalysts due to their remarkable reversible properties, higher theoretical specific capacitance, and capability to absorb visible light. Fewer active sites and low inherent electronic conductivities limit its supercapacitor and photocatalytic performances. To tackle these issues, a new composite structure, Bi₂MoO₆/BiVO₄/layered borophene hybrid, has been synthesized using a straightforward solvothermal method to establish a heterojunction structure. The synthesized Bi₂MoO₆/BiVO₄ heterostructure, incorporating varying amounts of borophene, was analysed using X-ray diffraction (XRD), Raman spectroscopy, electron microscopy (SEM and TEM), X-ray photoelectron spectroscopy (XPS), and UV–visible diffuse reflectance spectroscopy (UV–vis DRS). Integrating borophene into the Bi₂MoO₆/BiVO₄ hybrid improves electrical conductivity and active sites while expanding the contact area, thereby facilitating rapid faradaic redox reactions for supercapacitor and photocatalyst applications. At a current density of 2 A g⁻¹, the 5 % borophene-loaded Bi₂MoO₆/BiVO₄ electrode provides a high specific capacitance value of 638 F g⁻¹. It maintains a reasonable capacity retention rate (82.5 % of its initial specific capacity remains at 10 A g⁻¹). In addition, the photocatalytic degradation rate of the composite Bi₂MoO₆/BiVO₄ with layered borophene for 4-chlorophenol removal reaches 97 % after 60 min, demonstrating a significant enhancement compared to the performance of pure Bi₂MoO₆/BiVO₄ hybrid (67 %). Incorporating novel borophene into Bi₂MoO₆/BiVO₄ enhances photoinduced electron transfer and offers active reaction sites, thereby increasing the heterostructure's supremacy. This study provides valuable insights into utilising borophene to improve material performance for future energy storage and environmental cleanup applications.