[en] Highlights: • The rich and complex chemistry of tungsten was used to fabricate WO₃ nanostructures. • The morphology, size and catalytic properties of the nanostructures were adjusted. • Tree-like and spongy nanoplatelets were obtained depending on the ligand employed. • A photoelectrochemical improvement of 244% was obtained for the best sample. • These novel nanostructures can be used as high-performance photocatalysts. The rich and complex chemistry of tungsten was employed to synthesize innovative WO₃ nanoplatelets/nanosheets by simple anodization in acidic electrolytes containing different concentrations of complexing agents or ligands, namely F⁻ and H₂O₂. The morphological and photoelectrochemical properties of these nanostructures were characterized. The best of these nanostructures generated stable photocurrent densities of ca. 1.8 mA cm^{− 2} at relatively low bias potentials (for WO₃) of 0.7 V_Ag/AgCl under simulated solar irradiation, which can be attributed to a very high active surface area. This work demonstrates that the morphology and dimensions of these nanostructures, as well as their photoelectrochemical behavior, can be controlled by adjusting the ligand concentration in the electrolytes, hence providing an easy and non-expensive route to fabricate and customize high-performance nanostructured photocatalysts for clean energy production and environmental applications.