The study of copper oxide nanoparticles based on the pH varying during propolis-mediated synthesis: structure, optical properties, UV-block ability, and malachite green photodegradation

In third-world countries, the biosynthesis of multi-purpose copper oxide nanoparticles is a crucial solution for pollution, but studies on controlling their properties through internal structure are still limited. This work generated copper oxide nanoparticles (CONPs) using bee propolis as a reducing and capping agent, employing an ecologically benign, simple, inexpensive, and economical technique. The pH of this biosynthesis was varied (6.4, 7.8, 9.2, 10.4, and 11.7). The study computed various structural and optical parameters of biosynthesized CONP samples, revealing nonlinear changes with pH, including unit cell, Cu–O bond length, crystal size, microstrain, energy band gap, Urbach energy, and more. The current research has shown promising results in blocking ultraviolet rays effectively. The blocking parameters were calculated for CONPs samples, and it was found that the pH 8 sample had the best blocking capacity at both regions A and B (90.31 and 91.31%, respectively). The study effectively investigated CONPs’ potential as a catalyst for increasing dye photodegradation. The pH 6.4 sample showed the highest degradation rate (94.15%). The UV-blocking and photodegradation properties of the CONPs samples were explained using the structural and optical parameters.