Abstract ZnO nanoparticles (NPs) with uniform size are synthesized by anodizing a Zn sheet at 10 V in 1 M KCl electrolyte, forming randomly oriented nanosheets that transformed into spherical NPs after annealing at 500 °C for 1 h. These NPs are then homogeneously decorated with platinum quantum dots (Pt QDs) via a simple and efficient photodeposition method. Comprehensive characterizations by field‐emission scanning electron microscope (FESEM), X‐ray diffraction (XRD), high‐resolution transmission electron microscope (HRTEM), energy‐dispersive X‐ray spectroscope (EDAX), X‐ray photoelectron spectroscope (XPS), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), photoluminescence (PL), and Brunauer‐Emmett‐Teller (BET) confirmed the morphological evolution, crystal structure, composition, purity, successful decoration of ZnO with Pt QD uniformly, and high surface area. The pristine (ZnO NPs) and hybrid (Pt QDs–ZnO NPs) samples are evaluated for the photodecomposition of methylene blue (MB) under similar conditions. The Pt QDs–ZnO hybrid sample showed superior performance, achieving 99% MB degradation within 100 min compared to the pristine sample. This is attributed to higher surface area, formation of Schottky heterojunctions, reduced bandgap, efficient and improved charge transport. The synthesis and decoration procedures are simple, feasible, and universal for a series of hybrid metals‐oxide fabrication with controlled morphology and improved performance.