One-Step Fabrication of the ZnO/g-C₃N₄ Composite for Visible Light-Responsive Photocatalytic Degradation of Bisphenol E in Aqueous Solution

Abstract

The ZnO/g-C3N4 composite was successfully synthesized by a simple one-step calcination of a urea and zinc acetate mixture. The photocatalytic activity of the synthesized composite was evaluated in the degradation of bisphenol E (BPE). The morphology, crystallinity, optical properties, and composition of the synthesized composite were characterized by using various analytical techniques such as scanning electron microscopy (SEM), transmitted electron microscopy (TEM), field emission-electron probe microanalysis (FE-EPMA), nitrogen adsorption and desorption isotherm measurement, Fourier-transform infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The degradation rate of BPE with the ZnO/g-C3N4 composite was 8 times larger than that obtained with pure g-C3N4 at the optimal conditions. The excellent photocatalytic activity was attributed to the synergistic effect between the g-C3N4 and ZnO, which enhanced the efficiency of charge separations, reduced the e–/h+ pairs recombination, and increased the visible light absorption ability. The radical scavenger studies indicated that the •O2 – and h+ species were mainly responsible for the degradation of BPE. The stability test suggested the chemical and photostability of the synthesized composite. Two possible photocatalytical mechanisms have been suggested.

Black Phosphorus-Doped Graphitic Carbon Nitride with Aromatic Benzene Rings for Efficient Photocatalytic Hydrogen Production

“…The survey XPS spectra of the fabricated g-CN and BP/A-CN photocatalysts are shown in Figures S1c and S1d, respectively, confirming the presence of C, N, and O. The O 1s peak was observed at approximately 530 eV, which indicates the presence of adsorbed H 2 O or surface −OH groups on the samples . In addition, P was detected in the spectra of BP/A-CN.…”

“…50 The broad band observed between 3000 and 3500 cm −1 was due to the stretching modes of the −OH groups of surface-adsorbed water molecules and the deformed N−H bonds in the −NH 2 and −NH groups. 51 An intense peak was observed at 810 cm −1 , corresponding to the characteristic signal of triazine cycles. 52,53 Moreover, no additional aromatic benzene ring-or BP-related peaks were observed in the FTIR spectra of BP/A-CN.…”

“…The O 1s peak was observed at approximately 530 eV, which indicates the presence of adsorbed H 2 O or surface −OH groups on the samples. 51 In addition, P was detected in the spectra of BP/A-CN.…”

Review and Perspective on Rational Design and Interface Engineering of g-C3N4/ZnO: From Type-II to Step-Scheme Heterojunctions for Photocatalytic Applications

“…This technique also provides valid information on the purity of the components and the relative donor/acceptor properties of GCN/ZnO. The shift in the binding energies of C 1s, N 1s, O 1s, Zn 2p 3/2 , and Zn 2p 1/2 levels compared to their monophasic counterparts confirms the composite formation as well as the efficient interactions. ,,,,, The N 1s peaks show positive shifts, , while the O 1s and Zn 2p peaks displayed negative shifts, which manifest the role of electron-donating and -accepting properties of GCN and ZnO, respectively. ,,,, These changes were mainly attributed to the formation of Zn–N bonds, , which are probably achieved through the condensation reaction between the triazine amino group of GCN and the surface hydroxyl group of ZnO . Conversely, Zn 2p and O 1s levels shift to higher values if ZnO becomes oxygen deficient .…”

A graphitic carbon nitride photocatalyst with a benzene-ring-modified isotype heterojunction for visible-light-driven hydrogen production

“…Semiconductor-based photocatalysts have been successfully used to generate H 2 and O 2 through water splitting, 5–11 realize nitrogen fixation, 12–16 produce hydrocarbon fuels through CO 2 reduction, 17–22 degrade organic pollutants, 23–28 achieve bacterial disinfection, 29–31 and permit selective organic synthesis. 32–34 Essentially, this photocatalysis process involves enabling light absorption to generate electron–hole pairs, separating the excited charges, transporting the holes and electrons to the photocatalytic surface, recombining these charge carries into electron–hole pairs, and inducing a redox reaction on the surface using the charges created.…”