A comparative study on the photocatalytic performance of two third order NLO active nanocomposites (NiO-CdO and NiO-CuO) green synthesized using Psidium guajava leaf extract

[Display omitted] •NiO-CdO and NiO-CuO nanocomposites were green synthesized.•Comparison has been performed on their photocatalytic and third order NLO properties.•NiO-CuO nanocomposite seems to be highly polarized than the NiO-CdO nanocomposite. A comparative study has been performed in this paper on the photocatalytic activity and third order NLO properties of NiO-CdO and NiO-CuO nanocomposites green synthesized using Psidium guajava leaf extract. Under visible light illumination for about 90 min, the NiO-CdO nanocomposite degraded 86 % and the NiO-CuO nanocomposite degraded 91.5% of rhodamine B dye. Decreased crystallite size, larger specific surface area, enhanced visible light absorbing ability, least band gap value and greater dispersibility of CuO are responsible for the better degradation ability of the NiO-CuO nanocomposite than the NiO-CdO nanocomposite. The occurrence of reverse saturable absorption (RSA) effect from the Z-scan studies confirmed that both the composites are well suited for nonlinear optical and photonic devices. The high value of NLO susceptibility possessed makes the NiO-CuO nanocomposite highly polarized than the NiO-CdO nanocomposite.