<p>BaWO₄ nanoparticles doped and co-doped with various metal ions like Eu³⁺, Ag⁺, Li⁺, Zn²⁺ and Bi³⁺, etc., are synthesized using a simple polyol route. The synthesized NPs were characterized by XRD, TEM, XPS, EDX and a UV-VIS spectrometer. From the TEM image, the NPs are spherical in shape with an average particle size of 15&#xa0;nm. The band gap of the NPs is calculated using Tauc’s plot, and it is found to change with the concentration of co-dopant ions and the pH of the synthesis medium. The crystal size, crystallinity %, and lattice strain are calculated from the XRD data and it is found that BaWO₄:Eu³⁺, Ag⁺ NPs have a smaller size and larger strain. However, this nanoparticle demonstrated better catalytic activity in reducing the organic pollutant, 4-Nitrophenol (4-NP). The rate constant (k) for the reduction of 4-NP is 6.14 × 10⁻³ s^-1. The catalyst is stable and can be reused for five consecutive cycles.</p> Graphical Abstract <p></p>