ZnO nanoparticles modified with g-C3N4: Optical and structural properties

• ZnO NPs were incorporated into graphitic-carbon nitride (g-C 3 N 4 ) sheets. • structural, morphological, and optical properties of the nanocomposites were modified. • the band gap of ZnO and g-C 3 N 4 /ZnO decreased with increase in calcination temperature. • high temp. triggered a self-assembly of smaller ZnO due to enhanced surface reactivity. Herein, ZnO nanoparticles were incorporated into graphitic-carbon nitride (g-C 3 N 4 ) sheets to modify their optical properties and structural characteristics. The effects of different calcination temperatures on the structural, morphological, and optical characteristics of the nanocrystalline ZnO were investigated. The g-C 3 N 4 sheets were decorated by a simple reflux method and their physicochemical properties were studied using different characterization techniques. Finely bonded interfaces were generated between the ZnO and g-C 3 N 4 , which confirmed the successful formation of the composite. A microscopic analysis of the surface and internal morphologies of the composite revealed nanoparticles with an average diameter of 25 nm, whose size increased with temperature due to the self-assembly of smaller nanocrystallites. Optical measurement showed a reduction in the band gap energies that occurred in the composite as the percentage of ZnO decreased. This modification of structural and optical properties can be effectively utilized in the application of these materials in photocatalysis or optoelectronics.