Facile Synthesis of Nanoscale CuO and NiO via the PVA-Assisted Sol-Gel Method and Their Exploration in the Catalytic Epoxidation of Styrene

Nanoscale oxides of copper and nickel, with diameter 17 and 25 nm respectively, have been synthesized via an easy sol-gel method using polyvinyl alcohol. The method involves the simple dispersion of metal ions (M²⁺ = Cu or Ni) into the PVA gel and subsequent calcination of the dried gel at 400°C for 3 h. The synthesized oxide materials are characterized by different physical tools like TGA, powder XRD, SEM, TEM and DRS UV-visible spectroscopic technique. The oxides are found to be very efficient catalysts in the epoxidation of styrene. CuO gives 87% styrene conversion and 88% SO selectivity while, NiO gives 69% styrene conversion and 80% with TBHP as an oxidant at the end of 6 h. Both the catalysts can suitably be reused for several successive runs without appreciable loss in activity and selectivity. The cost–effective synthesis, excellent catalytic performance and reusability make these oxides promising catalysts for the industrial use.