Porous Mn-doped ZnO nanoparticles for enhanced solar and visible light photocatalysis

Abstract

Porous Mn-doped ZnO (ZnO:Mn) nanoparticles with an average diameter of ca. 21 nm were prepared by a simple and cheap solvothermal process involving no templates, post-synthetic annealing or etching. The particles produced were characterized by XRD, Raman spectroscopy, SEM, TEM, XPS, diffuse reflectance spectroscopy and BET surface area measurements and the effects of Mn 2+-doping on the structural, optical and photocatalytic properties of ZnO particles were investigated. The particles doped with 3 mol% Mn 2+ were found to exhibit the highest catalytic activity toward the photodegradation of the Orange II dye under solar light irradiation. Our results demonstrate that Mn 2+-doping shifts the optical absorption to the visible region, increases the specific surface area of the photocatalyst and reduces the recombination of electron-hole pairs. The influence of various operational parameters (amount of catalyst, concentration of dye and pH) on the photodegradation and the photocatalytic mechanism were studied. Finally, we demonstrated that the ZnO:Mn photocatalyst is stable and can be easily recycled up to ten times without any significant decrease in photocatalytic activity.

High performance Ce-doped ZnO nanorods for sunlight-driven photocatalysis

“…In a similar manner as described before [7,13], ZnO rods were synthesized by a solvothermal method based on the hydrolysis of Zn(OAc) 2 . Typically, in a three-necked flask equipped with a condenser and a dropping funnel, Zn(OAc) 2 ·2H 2 O (511 mg, 2.33 mmol) was dissolved in 35 mL ethanol.…”

“…In a similar manner as described before [7,13], the photocatalytic activity was evaluated by the degradation of an aqueous Orange II solution (10 mg/L) at room temperature under solar light irradiation. In a typical experiment, the ZnO:Ce rods (30 mg) were dispersed in 30 mL Orange II aqueous solution and the suspension was magnetically stirred under ambient conditions for 80 min in the dark to reach an adsorption-desorption equilibrium.…”

“…To shift ZnO absorption to the visible part of the solar spectrum and decrease charge recombination on the surface of the photocatalyst, doping of ZnO has been widely investigated in recent years [8–13]. Doping means introducing metal (Cu, Mn, Co, Al, …) or non-metal elements (C, N, S,…) into the ZnO crystal lattice to change its properties.…”

Rapid, controllable, one‐pot and room‐temperature aqueous synthesis of ZnO:Cu nanoparticles by pulsed UV laser and its application for photocatalytic degradation of methyl orange

“…Doping of ZnO NPs with transition metal ions affects the optical and photocatalytic activity properties by shifting the optical absorption toward the visible region . Hence, recently, the focus of many researchers has turned to doping of ZnO NPs with transition metals such as Mn, Cr, Fe, Ti, V, Co, Ni, Cu, Y, Zr, Nb, Pd, Ag and Cd . Copper (Cu) is considered as one of the most effective means of doping because of its physical and chemical properties are similar to those of zinc (Zn), its inexpensiveness and natural abundance can improve absorption, emission and photocatalytic activity of ZnO NPs .…”

Convenient synthesis of Mn-doped Zn (O,S) nanoparticle photocatalyst for 4-nitrophenol reduction

“…showed that Mn-doped ZnO increased the surface area, decreased electron-hole recombination, and finally improved the catalytic activity for methylene orange degradation [11]. Based on the above considerations, we choose the manganese as a dopant to improve the performance of Zn(O,S).…”