The global energy demand has driven the development of efficient and cost-effective visible-light-activated photocatalysts for the synthesis of fine chemicals. However, most high-performance photocatalysts possess bandgaps exceeding ∼3.0 eV, limiting their photocatalytic efficiency under visible light. In this study, Pd- and Pt-doped WO₃ nanoparticles were synthesized. Doping induced oxygen vacancies, which act as electron traps, reducing the bandgap and enhancing visible-light-driven photocatalytic activity. The photocatalytic performance was examined using hydroxymethylfurfural and benzyl alcohol as model substrates. The product yields for both substrates in the presence of Pd-doped WO₃ nanoparticles exceeded 95%. This work demonstrates a simple strategy for enhancing the solar-energy-driven photocatalytic efficiency of metal oxide nanoparticles, promoting sustainable fine chemical synthesis.