Exploration of the improving effect of Cd-doping on structural, photocatalytic, and biological properties of ZnO nanoparticles

ZnO and cadmium (Cd)-doped ZnO (Zn 1-x Cd x O) nanoparticles with various compositions (0.0 ≤ x ≤ 0.8) were synthesized by sol-gel method. Structural, morphological, and photocatalytic properties as well as blood compatibilities of Zn 1-x Cd x O nanoparticles were investigated. While X-ray diffraction (XRD) applying the Rietveld refinement method was used to characterize the structural properties, scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to investigate the surface morphology. It was found that the nanoparticles up to x < 0.03 Cd concentration had single phase of ZnO hexagonal wurtzite structure. Above x ≥ 0.03 Cd concentration, two phases (ZnO and cadmium oxide (CdO)) were observed. SEM images with different magnifications revealed the dense, quasi-spherical, and agglomerated morphology of Zn 1-x Cd x O nanoparticles. The elemental compositions of Zn 1-x Cd x O nanoparticles have also been studied by EDX analysis. The photocatalytic activities and blood compatibilities of Zn 1-x Cd x O nanoparticles were studied by the photocatalytic degradation tests of crystal violet (CV) and hemolysis tests and respectively. In the photocatalytic activity tests, two samples Zn 0.90 Cd 0.10 O and Zn 0.80 Cd 0.80 O stood out with photodegradation percentages of 69.9% and 72.8%. Among the Cd-doped nanoparticles, the Zn 0.40 Cd 0.60 O sample showed the highest blood compatibility with the weakest photocatalytic performance (degradation percentage; 32.2%). Structural properties, photocatalytic performance, and hemolytic potential of Zn 1-x Cd x O nanoparticles were investigated and compared with those of pure ZnO nanoparticles.