Abstarct: The first study investigates the application of Ti₃C₂Tx MXene modified with Bi₂S₃ and Bi₄V₂O₁₁ nanoparticles for the photocatalytic degradation of Toluidine Blue (TB) dye. The 2D-Ti₃C₂Tx/Bi₂S₃/Bi₄V₂O₁₁ nanocomposite exhibited the best photocatalytic. This difference in photocatalytic activity is attributed to the suppression of electron-hole recombination, leading to enhanced visible light absorption, prolonged carrier lifetime, and the generation of hydroxyl and peroxide radicals. The effects of various parameters such as catalyst amount, solution pH, initial TB concentration, and irradiation time on the photocatalytic degradation process were investigated and optimized using response surface methodology (RSM). The reusability of the photocatalyst showed that after five cycles, 2D-Ti₃C₂Tx/Bi₂S₃/Bi₄V₂O₁₁ maintained around 80% of its photocatalytic activity. The photocatalytic degradation mechanism was systematically explained using charge transfer pathways and band positions within the Z-scheme system, and this model was confirmed through radical scavenger tests and band structure calculations. In the second study, an innovative triple composite Ag₂SeO₃/Bi₀.₇₂Eu₀.₂₈VO₄/2D-Ti₃C₂Tx MXene (ASO/EBVO/2D-MXene) was synthesized and characterized for the first time using a combination of hydrothermal and co-precipitation methods. This composite was evaluated for photocatalytic degradation of the cationic dye methylene blue (MB) in a batch photocatalytic reactor under visible light irradiation. Characterization results showed that 2D-MXene significantly increased the specific surface area, improved light absorption capacity, and enhanced photothermal energy effects, ultimately boosting the photocatalytic activity of ASO/EBVO. To optimize the degradation process, RSM-CCD was used to systematically vary key parameters, including catalyst amount, pH, initial MB concentration, and irradiation time. PL analysis revealed that the recombination rate of electron-hole pairs decreased after the deposition of ASO/EBVO particles on MXene. The results demonstrated exceptional photocatalytic degradation performance, achieving a degradation efficiency of 94.22%, a high reaction rate constant of 0.0789 min⁻¹, and a mineralization efficiency of 77% within just 45 minutes without the need for any oxidants. The catalyst ASO/EBVO/2D-MXene showed excellent stability over four photocatalytic cycles. Radical scavenger tests indicated that hydroxyl and superoxide anion radicals played a crucial role in the process, leading to the proposal of a likely mechanism for MB degradation.