A mini-review on rare earth metal doped ZnO nanomaterials for photocatalytic remediation of waste water

Abstract

The mineralization and degradation of organic compounds present in waste water by heterogeneous photocatalysis has gained wide attention due to its effectiveness and tenancy to utilize UV-Visible solar light spectrum. The chemical stability, non-toxic character, magnificent electrical and optical properties have been recognized the ZnO as useful material for waste water treatment in environmental remediation technology. However, photocatalytic activity of ZnO limited to ultraviolet region because of its wide band gap (3.37eV). ZnO wide band gap obstruct photo-excitation for actual photocatalytic applications under abundant, safe and clean solar energy source. Many methods have been evolved in last decades to overcome this barrier. ZnO surfaces have been tailored with rare-earth metals to enhance its optical, surface and photocatalytic properties by different research groups. The doping with rare-earth metal ions enhanced the efficiency of ZnO photocatalyst by reducing band gap and shifted the absorbed wavelength to the visible region. This review paper compiles the attempts on modification of ZnO and their effect on photocatalytic activities by using rare earth metals.

Green Synthesis of Er-Doped ZnO Nanoparticles: An Investigation on the Methylene Blue, Eosin, and Ibuprofen Removal by Photodegradation

“…Notably, ZnO doped with rare earth cations has emerged as an effective method for photocatalytic applications [ 20 , 21 ]. In this context, rare earth ions, in addition to altering the defects concentration within the material, also function as electron traps, leading to increased hydroxyl radical production and consequently an enhancement in the photocatalytic efficiency of ZnO [ 22 , 23 ].…”

La-doped MIL-88B(Fe)–NH2: a mixed-metal–organic framework photocatalyst for highly efficient reduction of Cr(vi) in an aqueous solution

“…In this aspect, mixing rare earth elements (REEs) (La, Ce, Sb and so on) with these materials has been proven to be a feasible solution. [29][30][31] Opposite to d-block metals, REEmetals have unique electronic properties because of their 4f electron congurations that are shielded from outermost subshell 5s and 5p, and REE-metals have distinct electronic and magnetic properties that are not signicantly altered by coordinating ligands. Furthermore, REEs in general and lanthanum ( 57 La) in particular are able to act as electron traps thanks to a plenty of empty orbitals in 4f and 5d subshells, thereby slowing down the e − /h + recombination rate and consequently improving the efficiency.…”

A highly effective PANI@(Ce-Er) dual doped ZnO (PCEZ) nanocomposite as UV-light driven photocatalyst for degradation of MB dye: synthesis and characterization

“…This method offers a cost-effective and environmentally friendly alternative, harnessing solar energy for pollutant removal. Traditional treatment approaches often fall short of completely eliminating toxic wastewater effluents, merely transforming pollutants into different forms without complete removal from water bodies [6]. Semiconductor photocatalysis presents a sustainable solution for fully degrading toxic compounds into harmless inorganic substances [4,7].…”