“…Rectify this problem, numerous reports focused on doping ZnO with transition metal (Fe, Co, Mn) ions [19], non-metal (N, C, S) ions [20], and noble metals loading (Ag, Au, Pd) [21] have been carried out. Various techniques for the synthesis ZnO and Fe-doped ZnO nanoparticles are reported in the literature: hydrothermal method [22], combustion [23], and sol-gel method [24]. Among these synthesis methods, co-precipitation [25] is a flexible method for synthesizing the ZnO nanoparticles due to its low-cost, and easy to operate.…”