In this research work, we deposited rGO QDs on the surface of flower-shaped hierarchical Bi-Bi2WO6/EP (Expanded Perlite) floating photocatalyst via the facile-liquid-phase deposition route. The rGO QDs-Bi-Bi2WO6/EP is the EP-based floating nanocomposite which is consisting of 3C heterojunction (rGO QDs, Bi2WO6 and Bi nanoparticles). In as-fabricated rGO QDs-Bi-Bi2WO6/EP photocatalyst, rGO QDs-Bi-Bi2WO6 was successfully immobilized as superior-active photocatalyst component and the selection of EP was retainable price sustainable support and recyclability of the designed photocatalyst. The as-fabricated nanocomposites were comprehensively characterized by spectroscopic techniques and electrochemical reaction. The photocatalytic degradation performances of rGO QDs-Bi-Bi2WO6/EP nanocomposite was evaluated evidently by the degradation of hazardous organic contaminants (RhB and phenol) with high rate constants k of 0.23 min−1 and 0.047 min−1, respectively, under sun-like irradiation. The obviously enhanced photocatalytic efficacy of rGO QDs-Bi-Bi2WO6/EP should be attributed to uniform dispersion and floating behavior of the well-designed photocatalyst owing to enhanced visible-light absorption, photocurrent and high transfer efficiency of photoinduced electron-hole pairs due to close intimated contact between rGO QDs and Bi-Bi2WO6/EP. Display omitted •Fabrication of rGO QDs-Bi-Bi2WO6/EP floating photocatalysts using Expanded Perlite (EP) as a sustainable support•The photocatalytic efficiency of rGO QDs-Bi-Bi2WO6/EP nanocomposite was evaluated by degradation of organic contaminants under sun-like irradiations•rGO QDs-Bi-Bi2WO6/EP nanocomposite is floating material and easy to separate from water system