The need for efficient and sustainable catalysts to generate clean energy through water splitting is a requirement of the current era. In this study, TiO₂/CdS heterostructures were synthesized using hydrothermal reaction. To enhance the photocatalytic performances of TiO₂/CdS, BaO and Au were in-situ deposited via chemical reduction and hydrothermal treatment at 165 °C for 6 h. Finally Au-BaO@TiO₂/CdS catalysts were synthesized for photocatalytic hydrogen generation from water splitting. The optical and structural properties of catalysts were examined with FT-IR, XRD, Raman and UV–Vis-DRS techniques. The morphology and chemical properties of catalysts were obtained using EDX, AFM, XPS and SEM techniques. Photoreaction and H₂ production activities were monitored at Pyrex reactor (150 mL) and GC-TCD (Shimadzu-2014). The tunable fabrication approach provides a novel strategy for tailoring the properties of TiO₂/CdS heterostructures, allowing for optimization of their photocatalytic performance. The enhanced surface plasmon impact achieved through Au-NPs incorporation opens up new possibilities for improving the efficiency. The results demonstrate that Au-BaO@TiO₂/CdS catalysts exhibit significantly higher H₂ generation activity (13.54 mmol g⁻¹h⁻¹). This H₂ evolution activity was found higher than other catalysts i.e. TiO₂/CdS, BaO@TiO₂/CdS and Au@TiO₂/CdS. Higher catalytic activity in case of Au-BaO@TiO₂/CdS was attributed to the co-existence of BaO and Au-NPs. The Au-NPs provide hot electrons (via SPR effect) that increase the electron pool over the surfaces of TiO₂/CdS heterostructures. During photoreaction, BaO assists the transfer of photoexcited electrons from TiO₂/CdS system to the active centers (i.e. Au cocatalysts). In addition, various factors that affect the H₂ production rates (i.e. pH, temperature, catalyst dose and effect of light intensity) were evaluated and discussed.