Synthesis of Core/Shell ZnO/rGO Nanoparticles by Calcination of ZIF-8/rGO Composites and Their Photocatalytic Activity

Abstract

A facile two-step method was developed to prepare core/shell ZnO/rGO particles from ZIF-8/rGO composites. ZIF-8 particles were first grown at the surface of rGO sheets. Next, ZIF-8 particles were transformed into ZnO particles by thermal decomposition under air at 500 °C. All materials were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, thermogravimetric analysis, and Brunauer–Emmett–Teller analyses. Results obtained show that ZIF-8 particles strongly associate with rGO sheets and that the calcination of this material produces porous core/shell ZnO/rGO particles with an average diameter of ca. 40 nm. The wt % of rGO associated with ZIF-8 particles was varied from 5 to 20%. The ZnO/rGO (10%) particles exhibit the highest photocatalytic activity for the degradation of the Orange II dye under simulated solar light irradiation of weak intensity (5 mW/cm 2 ). This high photocatalytic activity was demonstrated to originate from superoxide O 2 •– radicals due to the efficient trapping of photogenerated electrons in ZnO by rGO.

Growth of ZnO Nanorods on Graphitic Carbon Nitride gCN Sheets for the Preparation of Photocatalysts with High Visible‐Light Activity

“…3.2 eV and a large exciton binding energy (60 meV at room temperature). ZnO exhibits good photosensitivity, high carrier mobility and is therefore used in numerous photocatalytic applications but also in photodetectors and in solar cells ,. However, the use of ZnO as photocatalyst for practical applications is generally restricted because (1) it can only be activated by UV‐light due to its wide bandgap, (2) photogenerated electron/hole pairs exhibit a short lifetime and (3) its photocorrosion.…”

“…Doping of ZnO with metal,, or non‐metal elements, coupling with metal nanoparticles or with graphene derivatives,, or constructing heterostructures with low bandgap semiconductors, have been demonstrated to be effective strategies to enhance both the charge separation and the visible light photoresponse of ZnO‐based photocatalysts.…”

Synergistic RGO/Black TiO2/2D‐ZIF‐8 Ternary Heterogeneous Composite with Highly Efficient Photocatalytic Activity

“…In XRD spectra of RGO/B−TiO 2 , the disappearance of GO diffraction peaks indicated that GO was reduced to RGO under the hydrothermal condition. As previously reported, a peak at 2θ=25.1° was attributed to the layer spacing of RGO . Therefore, the RGO layer reflection combined with the characteristic peak of TiO 2 at 25.3° (Figure d).…”

“…As previously reported, a peak at 2θ = 25.1°was attributed to the layer spacing of RGO. [42] Therefore, the RGO layer reflection combined with the characteristic peak of TiO 2 at 25.3° (Figure 2d). Compared with RGO/BÀ TiO 2 , the peaks of ZIF-8 at 2θ = 7.4°and 12.7°could be observed in Figure 2e, which proved the successful preparation of the ternary RGO/BÀ TiO 2 /2D-ZIF-8 composite.…”

High‐Performance Microwave Absorption of MOF‐Derived Core‐Shell Co@N‐doped Carbon Anchored on Reduced Graphene Oxide

“…[30][31][32] So, coupling RGO with magnetic metals could achieve a optimized impedance match and such dielectric/magnetic composites have been widely studied to obtain better absorbents. [33][34] Wei et al synthesized nanocomposite of Fe 3 O 4 @SnO 2 /RGO, the RLmin value is À 45.5 dB. [35] Liu et al reported Co 0.33 Ni 0.67 alloy and RGO composites as absorber, the absorption bandwidth (RL < À 10 dB) reaches up to 14.0 GHz.…”