New Insights into Cu/Cu₂O/CuO Nanocomposite Heterojunction Facilitating Photocatalytic Generation of Green Fuel and Detoxification of Organic Pollutants

Abstract

Cu/Cu 2 O/CuO nanocomposites were synthesized using the simple wet chemical approach for the production of dihydrogen as a potential fuel source and for the detoxification of dyes. The formation of Cu/Cu 2 O/ CuO nanocomposites is confirmed by powder X-ray diffraction, whereas the W-H plot revealed the average particle size of nanocomposite approximately 17 nm, which is in good agreement with the Scherrer method and transmission electron microscopy analysis. The uniform distribution of Cu and O elements was supported by the elemental mapping of the nanocomposite. Band gaps of CuO and Cu 2 O were found to be 1.71 and 1.92 eV, respectively, using diffuse reflectance spectroscopy spectra and Kubelka−Munk functions. The oxygen vacancies in the nanocomposite are confirmed by various analytical spectroscopic techniques, such as electron paramagnetic resonance, Raman, photoluminescence, and X-ray photoelectron spectroscopy (XPS) spectra. The significant boost in the performance of the fabricated nanocomposite was observed and is attributed to the formation of a heterojunction and existence of oxygen vacancy. The nanocomposite demonstrated proficiency in the photocatalytic splitting of water for the production of hydrogen. The maximum hydrogen generation yield (68 μmol g −1 ) was observed for Cu/Cu 2 O/CuO nanocomposites along with NiO (co-catalyst) and methanol as a hole scavenger as well as an electron donor. Moreover, the degradation of congo red (CR) and malachite green (MG) dyes was also investigated and the efficiency of the nanocomposite was found to be 80 and 60%, respectively, after 120 min of light irradiation. The stability of nanocomposites after photocatalysis was investigated by the XPS spectrum of the nanocomposite. Explicitly, the area and broadening of the O 1s XPS spectrum demonstrated higher degradation of CR dye as compared to MG dye.

Insights into the Degradation Mechanisms of TCH by Magnetic Fe3S4/Cu2O Composite

“…The XPS spectra of Cu, O, Fe, and S species are presented in Figure b–d. The binding energies for Cu 2p 3/2 and Cu 2p 1/2 from the Cu 2 O and Fe 1 Cu 1 composite in Figure b were displayed at 932.3, 934.9, and 952.3 eV, respectively, which can be ascribed to the lattice Cu + of Cu 2 O. − A peak at a binding energy value of 944.0 eV was correlated with CuO, which may be derived from the oxidation of small amounts of Cu 2 O. Figure c shows that the peak shape of O 1s is an asymmetric structure, which can be divided into two peaks at 530.2 and 531.6 eV by the Gauss–Lorentz fitting method, which are attributed to the lattice oxygen of Cu 2 O and adsorbed oxygen of chemisorption, respectively …”

Comprehensive analysis of cationic dye removal from synthetic and industrial wastewater using a semi-natural curcumin grafted biochar/poly acrylic acid composite hydrogel

“…12 Replacing conventional dyes with modern dyes with complex structures and higher chemical, thermal, photochemical, 13 and biological degradation resistance, making their degradation even more complicated. 14 Dyes-colored water can impede sunlight penetration and elevate microorganism oxygen demand. 15 Even a trace amount of dyes (1.0 mg L −1 ) can be unsafe for human and animal consumption due to their carcinogenicity, reproductive and developmental toxicity, neurotoxicity, and chronic toxicity.…”

Understanding the role of oxygen-vacancy defects in Cu2O(111) from first-principle calculations

“…It is crucial for further advancements in abundant Cu 2 O-based materials, particularly for the development of p-n heterojunctions for Cu 2 O-based photovoltaic devices [24] and the adsorption and dissociation of gases (O 2 [26], NO [27], CS 2 [28] etc) On photocatalysis, Khasanah et al [29] pointed out that the dominating effect of V O in Cu 2 O remains to be determined, because it exerts opposite effects by facilitating the photocharge recombination and reducing the high reaction overpotential at the interface. Further, Kumar et al [30] demonstrate that due to the suitable band gap, Cu 2 O are widely employed as the photocathode and the photoanode in photoelectrochemical water splitting, and enhance its productivity by tuning nanostructures, such as by introducing defects or dopants. In lithium-ion battery investigation, Cu 2 O-based materials are commonly used as electrodes where V O defects can improve the reaction kinetics by reducing the energy barrier of ion intercalation and accelerating the charge transfer [31].…”