Multifunctional and smart Er2O3–ZnO nanocomposites for electronic ceramic varistors and visible light degradation of wastewater treatment

Photocatalytic activity of hybrid Ag/Er:ZnO nanoparticles synthesized by pulsed laser ablation in distilled water

“…The observed peak at around 29.3°(labeled by *) is assigned to the (222) plane of Er 2 O 3 dopant [11,22,23,25,62,63]. Thus, during the sintering process, at 1 mol % Er 2 O 3 doping concentration, some of erbium ions might be aggregated and form a separate phase of Er 2 O 3 in the sintered pellet target.…”

“…In addition, a slight shift of the ZnO diffraction peak (002) toward lower angle was observed in Er:ZnO sample. This could reveal that some of Er 3+ ions (with ionic radius (0.89 Å) higher than that of Zn 2+ (0.74 Å)) were partly substituted into the ZnO lattice [21,25,64] during the sintering process, and/or the laser ablation. Furthermore, the XRD peak intensity is slightly increased in Er-doped ZnO NPs.…”

“…However, in the dye solution containing the ZnO, Ag/ZnO, Er:ZnO, and Ag/Er:ZnO colloidal NPs, the degradation efficiency obviously enhanced to be 79.7, 88, 94.1, and 96.4%, respectively, indicating the photocatalytic nature of the laser-ablated colloidal nanoparticles. The plot of Ln (C o /C t ) versus the UV illumination time interval t (figure 7(b)) shows that the photocatalytic degradation process exhibits a pseudo first-order kinetics, with a rate constant k, as follows [25,55]:…”

“…Moreover, many reported studies have shown that ZnO modified with appropriate dopants (such as rare-Earth (RE) elements and noble metals) can exhibit improved properties compared to the pristine ZnO in different applications [8][9][10][11][12][13][14][15]. For example, the photocatalytic properties of ZnO nanoparticles have been enhanced upon doping with europium ions (Eu 3+ ) [16][17][18], erbium ions (Er 3+ ) [19][20][21][22][23][24][25], and by hybridization with selected noble metal such as silver (Ag) [26][27][28][29][30][31][32][33][34][35][36][37][38][39]. The observed effective separation of the photo-generated charges in ZnO has been attributed to the electron-scavenger effect of the noble metal [26] and the point defects introduced by RE-doping [23].…”