Fluorinated Reduced Graphene Oxide-Encapsulated ZnO Hollow Sphere Composite as an Efficient Photocatalyst with Increased Charge-Carrier Mobility

Abstract

Zinc oxide (ZnO) hollow spheres were prepared by the hydrothermal method and encapsulated with fluorinated reduced graphene oxide (FRGO) using a tetra-n-butylammonium bromide (TBAB) linker to give an FRGO/ZnO composite. X-ray diffraction and microscopic studies revealed their hexagonal-wurtzite structure, spherical morphology, and size of the crystallite to be 26.7 nm. Diffuse reflectance UV–visible spectroscopy showed an optical band gap and semiconductive nature of the composite. Atomic force microscopy images show the surface topography of FRGO-encapsulated ZnO hollow spheres. The photoluminescence spectra depicted the electron–hole pair recombination order to be ZnO > RGO/ZnO > FRGO/ZnO. The electrochemical impedance spectroscopy (EIS) demonstrates the increased charge-carrier mobility of the FRGO/ZnO composite; the R ct values of ZnO, RGO/ZnO, and FRGO/ZnO were found to be 6.18 × 103, 4.07 × 103, and 3.45 × 103 Ω, respectively. All the three materials were employed as photocatalysts in the degradation of methylene blue under UV-365 nm radiation and the results exposed the higher photocatalytic activity of reduced fluorinated graphene oxide/ZnO than RGO/ZnO and bare ZnO hollow spheres. The increased photocatalytic activity of the composite is due to the enhanced vectorial transport of charge carriers at the interface of the FRGO/ZnO composite and suppression of charge-carrier recombination. The presence of fluorine in the RGO sheet introduces additional defects and leverages heterogeneous electron transport. In turn, mobility of light-generated charge carriers is increased and results in suppression of their recombination, which facilitates the photocatalytic process.

Accordion‐Like Fluorinated Graphite Nanosheets with High Power and Energy Densities for Wide‐Temperature, Long Shelf‐Life Sodium/Potassium Primary Batteries

“…[38] New diffraction peaks appeared near 13° and 41° after fluorination, which can be analyzed as the diffraction of ( 001) and (100) lattice planes of fluorinated carbon. [39,40] The 2θ value for (001) peaks is 14.31, 12.63, and 12.88 for FGNSs-0.6, FGNSs-0.9, and FGNSs-1.0, respectively. The corresponding interlayer spacing of d 001 is calculated to be about 0.62, 0.70, and 0.69 nm.…”

Inside‐and‐Out Semiconductor Engineering for CO2 Photoreduction: From Recent Advances to New Trends

“…Photocatalysts with 3D structure, such as nanosheets‐assembled flowers, [ 227–233 ] hollow spheres, [ 234–243 ] and hierarchical NW arrays, [ 244–252 ] have been widely developed. Due to their special features, including high specific surface area and high light utilization, they always demonstrate excellent photocatalytic CO 2 reduction performance.…”

EPR Investigation on Electron Transfer of 2D/3D g‐C3N4/ZnO S‐Scheme Heterojunction for Enhanced CO2 Photoreduction

“…stabilities, has been studied extensively for photocatalytic applications. [26][27][28][29][30][31][32][33][34] Particularly, ZnO hollow structures showed promising performance within photocatalytic devices. Such enhanced activity was attributed to the interior hollow volume that inherits them with enhanced light absorption upon multiple light reflections, enlarged available surface area for higher adsorption of reactant ions/molecules, and short yet accessible channels for efficient diffusion of charges, reactants, and/or product molecules.…”

“…Such enhanced activity was attributed to the interior hollow volume that inherits them with enhanced light absorption upon multiple light reflections, enlarged available surface area for higher adsorption of reactant ions/molecules, and short yet accessible channels for efficient diffusion of charges, reactants, and/or product molecules. [34][35][36][37][38][39][40] Although several works have reported g-C 3 N 4 /ZnO as an effective photocatalytic system, [41,42] the integration of 2D g-C 3 N 4 layers with 3D ZnO HS in a one-pot manner has not been reported before. Additionally, harsh chemical, thermal, or mechanical conditions are needed within the literature to exfoliate g-C 3 N 4 layers from the bulk structure.…”