A hierarchical Bi₂WO₆/BiFeWO₆ architectures were synthesized by a facile and low-cost hydrothermal approach using Bi₂WO₆ flower structure as an efficient backbone for the growth of layered BiFeWO₆ sheets. The conduction band offset and bandgap of flower like Bi₂WO₆ were tailored strategically as active photocatalyst under visible light and suitable for water reduction. By developing n-n heterojunction between Bi₂WO₆ and BiFeWO₆, the active surface area as well as number of free charge carriers have been enhanced which may boost the catalytic redox reactions. The physicochemical properties of the heterojunction was characterized to investigate the phase, morphology, thermal stability, light absorption and oxidation states of the elements. The photocatalytic activity of Bi₂WO₆/BiFeWO₆ heterojunction was investigated through H₂ generation via water splitting under visible light, where four-fold enhanced activity achieved for heterojunction compared to bare Bi₂WO₆. Further, photoelectrochemical properties were studied to determine the band edge potentials and illustrate the enhanced photoresponse for heterojunction. The Bi₂WO₆/BiFeWO₆ heterojunction showed lower charge transfer resistance compared to Bi₂WO₆, owing to efficient charge separation at electrode-electrolyte interface. The synergistic effect of high surface area, lower recombination rate and the suitable band edge potentials led to high catalytic activity, good cycling stability and superior photoelectrochemical response of heterojunction. This work provide insight into the synergistic effect of hierarchical n-n heterojunction and opens up an avenue for rational design of photocatalyst for water splitting and H₂ generation.