Preparation and assessment of photocatalytic performance of c-Si/MoS2/TiO2 heterostructure for removal of Rhodamine B under low-power UV irradiation

Photocatalytic systems are emerging technologies that offer an efficient and sustainable solution for the degradation of organic dyes. The widespread deployment of crystalline silicon in photovoltaic applications has made it an interesting candidate for photocatalytic architecture. In this work, a Si/MoS 2 /TiO 2 heterostructure system was employed for the degradation of Rhodamine B (RhB), a commonly used organic dye in textile industries, under low-power UV irradiation. A texturization study was conducted on the silicon surface to determine the optimal treatment duration, enabling light trapping and enhanced charge generation. In parallel, liquid-phase exfoliation was applied to MoS 2 powders to reduce the number of layers and effectively tune the bandgap of the material. The exfoliated MoS 2 was characterized by UV–Vis spectroscopy revealing a significant shift of bandgap from 1.272 to 1.424 eV, confirming successful layer reduction. SEM imaging and charge-carrier lifetime measurements were performed on the silicon substrate. The results confirmed the formation of a uniform pyramidal textured silicon surface with an average size of 7.57 μm at 20 min of treatment, corresponding to a maximum carrier lifetime of 12.3 μs. The resulting heterostructure exhibited a high photocatalytic degradation efficiency, achieving over 87% RhB degradation after 3 h of irradiation. A stability test revealed a moderate loss of performance of about 20% after three cycles, indicating good stability of the system. These findings confirm the efficiency of silicon-based heterostructures as effective photocatalysts for low-power UV-driven wastewater treatment applications.