Preparation of 2D–1D black phosphorus/Bi–BTC composites with effective electron separation for excellent visible-light photocatalytic activity

In this study, we propose a novel composite system combining black phosphorus (BP) nanosheets with Bi-MOF to overcome the three main limitations of conventional photocatalysts, narrow photoresponse range, high carrier recombination rate, and poor stability. The unique properties of BP, characterized by their narrow bandgap, are leveraged to expand the spectral response spectrum. The heterojunction interface facilitates the directed separation of charge carriers, while the MOF skeleton provides protection against environmental degradation, thus enhancing overall stability. In the experiments, a combined hydrothermal-ultrasonic approach was employed to ensure close interfacial contact between BP and rod-like Bi–BTC, resulting in the formation of an effective heterojunction. The BP/Bi–BTC composite exhibits remarkable broad-spectrum absorption characteristics, substantially expanding the photoresponse range and effectively inhibiting carrier complexation. Concurrently, the protective Bi–BTC skeleton successfully prevents direct environmental exposure of black phosphorus, enhancing its stability. The BP/Bi–BTC composite displays exceptional photocatalytic performance in the degradation of RhB, achieving an impressive degradation efficiency of 98.7% within just 30   min of UV–visible irradiation. This performance surpasses both single-component systems and conventional catalysts. Notably, the material retains 94.1% of its initial activity even after three consecutive catalytic cycles. Characterization analysis elucidated the interfacial charge transfer and uncovered the underlying catalytic mechanism of the composite system.