Bandgap engineering approach for designing CuO/Mn3O4/CeO2 heterojunction as a novel photocatalyst for AOP-assisted degradation of Malachite green dye

Abstract

A ternary nanohybrid CuO/Mn3O4/CeO2 was developed in the present work using a co-precipitation-assisted hydrothermal method. The designed photocatalyst's structural, morphology, elemental composition, electronic states of elements, and optical properties were studied using corresponding analytical techniques. Results from PXRD, TEM/HRTEM, XPS, EDAX, and PL showed that the desired nanostructure had formed. Using Tauc's energy band gap plot, it was determined that the nanostructures band gap was ~ 2.44 eV, which showed the band margins of the various moieties, CeO2, Mn3O4, and CuO, had modified. Thus, improved redox conditions led to a substantial decrease in the recombination rate of electron–hole pairs, which was further explained by a PL study in that charge separation plays a key role. Under exposure to visible light irradiation for 60 min, it was revealed that the photocatalyst achieved 98.98% of photodegradation efficiency for malachite green (MG) dye. The process of photodegradation proceeded according to a pseudo-first-order reaction kinetic model with an excellent rate of reaction of 0.07295 min−1 with R2 = 0.99144. The impacts of different reaction variables, inorganic salts, and water matrices were investigated. This research seeks to create a ternary nanohybrid photocatalyst with high photostability, visible spectrum activity, and reusability up to four cycles.

Cationic and oxygen defect modulation for tailoring the bandgap and room temperature ferromagnetism of CuO via multiple d-block cations

“…The calculated indirect band gap energy (the electron momentum is not conserved in the transition) for pristine CuO is 1.26 eV, which is notably lower than the previously stated values for undoped CuO. 3 The electronic transition from the hybridized O-2p valence band to the Cu-3d conduction band provides a measure of the band gap in undoped CuO. However, in this study, the lower bandgap values of pristine CuO can be attributed to the presence of surface oxygen vacancy states, as observed in XPS.…”

“…The demand for metal oxide (MO) nanostructures is growing and has attracted noticeable research interest due to their alluring fundamental properties like structural, optical, and magnetic properties, which enable their multidisciplinary implementation in various sensors, supercapacitors, solar cells, catalysis, photocatalysis, spintronic devices, and so on. 1–7 Particularly, p-type cupric oxide (CuO) semiconducting nanocrystals (NCs) are receiving more attention as multifunctional materials because of their fundamental properties, i.e. , narrow bandgap (1.2–1.8 eV) and room-temperature ferromagnetism (RTFM).…”

“…The demand for metal oxide (MO) nanostructures is growing and has attracted noticeable research interest due to their alluring fundamental properties like structural, optical, and magnetic properties, which enable their multidisciplinary implementation in various sensors, supercapacitors, solar cells, catalysis, photocatalysis, spintronic devices, and so on. [1][2][3][4][5][6][7] Particularly, p-type cupric oxide (CuO) semiconducting nanocrystals (NCs) are receiving more attention as multifunctional materials because of their fundamental properties, i.e., narrow bandgap (1.2-1.8 eV) and room-temperature ferromagnetism (RTFM). 8 CuO also possesses environmental compatibility, non-toxicity, eco-friendliness, high theoretical capacity, and increasing susceptibility at low temperatures, which make it a potential contender for the energy domain, antibacterial applications, light-emitting diodes (LEDs), and degradation of organic pollutants.…”

Cationic and Oxygen Defects Modulation for Tailoring Bandgap and Room Temperature Ferromagnetism of CuO via Multiple d-Block Cations

“…The demand for metal oxide (MO) nanostructures is growing and has attracted noticeable research interest due to their alluring fundamental properties like structural, optical, and magnetic properties, which enable their multidisciplinary implementation in various sensors, supercapacitors, solar cells, catalysis, photocatalysis, spintronics devices, and so on [1][2][3][4][5][6][7] . Particularly, p-type cupric oxide (CuO) semiconducting nanocrystals (NCs) are receiving more attention as a multifunctional material because of their fundamental properties, i.e., narrow bandgap (1.2-1.8 eV) and room-temperature ferromagnetism (RTFM) 8 .…”