Preparation of ZIF-8 nanoparticle-decorated Zn2GeO4 nanorods with high photocatalytic performance for chromium (VI) reduction

Abstract

a b s t r a c tZeolitic imidazolate framework-8 (ZIF-8) nanoparticles decorated Zn 2 GeO 4 composites, denoted as ZIF-8@Zn 2 GeO 4 , were prepared through a chemical deposition route. The obtained ZIF-8@Zn 2 GeO 4 heterostructure was characterized by X-ray diffraction, scanning electron microscopy, infrared spectroscopy, and UV-Vis diffuse reflectance spectroscopy. The results showed that the ZIF-8 nanoparticles have been successfully assembled on the surface of Zn 2 GeO 4 nanorods, and 100 mg of ZIF-8@Zn 2 GeO 4 photocatalyst can reduce nearly 100% of Cr(VI) in aqueous solution (100 mL 1 × 10 -5 mol L -1 ) in 90 min under UV-light irradiation. The obtained ZIF-8@Zn 2 GeO 4 photocatalysts exhibited 14.1 and 1.8 times higher photocatalytic activity toward the photoreduction of Cr(VI) than pure Zn 2 GeO 4 nanorods and ZIF-8 under UV light irradiation, respectively. The synthetic strategy used is also promising for implementing MOF structures in other semiconductor photocatalysts for reduction of Cr(VI) to Cr(III) with enhanced photocatalytic performance and high stability in aqueous media.

Recent Progress in the Development of MOF-Based Photocatalysts for the Photoreduction of Cr(VI)

“…In another study, ZIF-8 NPs were deposited on the surface of Zn 2 GeO 4 nanorods, and the resulting composite reduced the Cr (VI) with an efficiency of ∼100% within 90 min under UV light irradiation. 157 In other words, the composite exhibited 14.1 and 1.8 times higher photoactivity than Zn 2 GeO 4 and ZIF-8, respectively. Similarly, a MoO 3 @ZIF-8 core−shell composite was fabricated via the growth of ZIF-8 on the surface of as-prepared MoO 3 nanorods with a shell thickness of ∼20 nm.…”

“…The shell enhanced the selective adsorption and permeation of small CrO 4 2– ions (4 Å) into the small pores of the shell (3.4 Å), whereas the MB with a bigger size (cross-section size of 8 Å) was not able to permeate into the ZIF-8 aperture. In another study, ZIF-8 NPs were deposited on the surface of Zn 2 GeO 4 nanorods, and the resulting composite reduced the Cr (VI) with an efficiency of ∼100% within 90 min under UV light irradiation . In other words, the composite exhibited 14.1 and 1.8 times higher photoactivity than Zn 2 GeO 4 and ZIF-8, respectively.…”

Controlled Growth of a Photocatalytic Metal–Organic Framework on Conductive Plates by Mixing Direct Synthesis and Postsynthetic Modification Strategies

“…Recently, there has been a growing interest in the development of photocatalytically active MOF materials for solar energy conversion/storage applications (e.g., water splitting or CO 2 reduction) in the visible spectrum of light. To this end, the photocatalytic activity of several MOF materials has been explored, where promising results have been obtained in the domains of photodegradation of organic pollutants and CO 2 reduction. − Among the most interesting results are those obtained with a modified Zr-MOF, UiO-67 (based on a biphenyl dicarboxylic acid (BPDC) ligand), which is known for its high chemical and thermal stabilities, in addition to its ability to accommodate different isostructural linkers, metals, or defects in its structure . Of note, because it is possible to dope the UiO-67 MOF structure with transition metal complexes, based on Ir, Re, or Ru ions bound to a bipyridine dicarboxylic acid (BPyDC) ligand, and, thus, to add a “light antenna”, there have been many reports in the literature − of materials that have been efficient for the photocatalytic reduction of CO 2 , and optical and photocatalytic properties have been reported.…”

Atomically Thin Zn2GeO4 Nanoribbons: Facile Synthesis and Selective Photocatalytic CO2 Reduction toward CO

“…Atomically thin nanomaterials are considered an ideal platform to afford abundant catalytic active sites, which can trigger CO 2 reduction reactions. − Furthermore, the atomic-scale thickness shortens charge transfer distance, allows the photoexcited charge carriers to easily migrate onto surface from the interior, and hence improves the utilization rate of the photogenerated carrier. ,, Zn 2 GeO 4 (ZGO) is a typical wide-band gap semiconductor ( E g = 4.68 eV). Varieties of one-dimensional (1D) nanostructures have been synthesized, such as nanorods, nanowires, and nanoribbons. − Those structures as promising photocatalysts were demonstrated to display outstanding performance for a variety of photocatalytic reactions, such as water splitting, CO 2 reduction, and the degradation of organic pollutants. − …”