Mg-Doped ZnO Nanoparticles for Efficient Sunlight-Driven Photocatalysis

Abstract

Magnesium-doped ZnO (ZMO) nanoparticles were synthesized through an oxalate coprecipitation method. Crystallization of ZMO upon thermal decomposition of the oxalate precursors was investigated using differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques. XRD studies point toward a significant c-axis compression and reduced crystallite sizes for ZMO samples in contrast to undoped ZnO, which was further confirmed by HRSEM studies. X-ray photoelectron spectroscopy (XPS), UV/vis spectroscopy and photoluminescence (PL) spectroscopy were employed to establish the electronic and optical properties of these nanoparticles. (XPS) studies confirmed the substitution of Zn(2+) by Mg(2+), crystallization of MgO secondary phase, and increased Zn-O bond strengths in Mg-doped ZnO samples. Textural properties of these ZMO samples obtained at various calcination temperatures were superior in comparison to the undoped ZnO. In addition to this, ZMO samples exhibited a blue-shift in the near band edge photoluminescence (PL) emission, decrease of PL intensities and superior sunlight-induced photocatalytic decomposition of methylene blue in contrast to undoped ZnO. The most active photocatalyst 0.1-MgZnO obtained after calcination at 600 °C showed a 2-fold increase in photocatalytic activity compared to the undoped ZnO. Band gap widening, superior textural properties and efficient electron-hole separation were identified as the factors responsible for the enhanced sunlight-driven photocatalytic activities of Mg-doped ZnO nanoparticles.

Surfactant-less Sol-Gel Technique for the Synthesis of Mg-ZnO Nanoparticle

“…The surface area of Mg-ZnO sample was found to be bigger than ZnO (Table 2). The adsorption-desorption isotherms (Figure 3) of the Mg-ZnO to be of type IV in nature and exhibited a H1 hysteresis loop, which is typical of mesopores solids [18,19]. …”

Influence of Mg dopant on photocatalytic properties of Mg-doped ZnO nanoparticles prepared by sol–gel method

“…To improve its photocatalytic activity, Mg-doped ZnO has received considerable attention because Mg has similar ionic radius and can extend the absorption wavelength from UV-A (320400 nm) to UV-B (280320 nm) and UV-C (200280 nm) regions. 8), 9) In the present study, Mg-doped ZnO with different Mg contents was prepared by solgel method and used as a photocatalyst for degradation of methylene blue (MB). The effect of Mg dopant on phase, morphology and photocatalytic activity of ZnO was investigated and discussed in this report.…”

Near Infrared Plasmonic Gas Sensing with Doped Metal Oxide Nanocrystals

“…Doping has been shown to influence the optical and electrical properties of ZnO, with beneficial effects for its catalytic and sensing performances [1]. In particular, trivalent cations (i.e., Al 3+ and Ga 3+ ) as substitutional dopants for zinc have been extensively studied, mostly for application in transparent conductors (TCO).…”