Enhanced photocatalytic degradation of malachite green dye by highly stable visible-light-responsive Fe-based tri-composite photocatalysts

Abstract

A novel visible-light-sensitive ZnVFeO4 photocatalyst has been fabricated by the precipitation method at different pH values for the enhanced photocatalytic degradation of malachite green (MG) dye as a representative pollutant under visible light irradiation at neutral pH conditions. The structure and optical characteristics of the prepared photocatalysts were investigated by XRD, FTIR, N2 adsorption–desorption, TEM, diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) analyses. In addition, the photocatalytic activity of ZnVFeO4 photocatalysts superior the efficiency to be more than that of the mono and bi-metal oxides of iron and iron zinc oxides, respectively. The best sample, ZnVFeO4 at pH 3, significantly enhances the degradation rate under visible light to be 12.7 × 10−3 min−1 and can retain a stable photodegradation efficiency of 90.1% after five cycles. The effect of the catalyst dose and the initial dye concentration on the photodegradation process were studied. This promising behavior under visible light may be attributed to the low bandgap and the decreased electron–hole recombination rate of the ZnVFeO4 heterostructures. The scavenger experiment confirmed that the hydroxyl radicals induced the MG photodegradation process effectively. Hence, the ZnVFeO4 is a reliable visible-light-responsive heterostructure photocatalyst with excellent potential for the photodegradation of organic pollutants in wastewater treatment.

Exploring multifunctional applications of a luminescent covalent triazine polymer in acid vapour sensing, CO2 capture, dye removal, and turn-off fluorescence sensing of dichromate ions

“…6(d) depicts the Langmuir–Hinshelwood model fitting with an R 2 value of 0.9952, and the rate constant ( k ) is 0.0168 min −1 , which is comparable or even better with respect to earlier reported studies. 57–59…”

“…6(d) depicts the Langmuir-Hinshelwood model fitting with an R 2 value of 0.9952, and the rate constant (k) is 0.0168 min À1 , which is comparable or even better with respect to earlier reported studies. [57][58][59] Furthermore, the degradation mechanism of MG was investigated by adding free radical scavengers into the reaction medium. 1 mM of IPA ( OH scavenger), EDTA (h + scavenger), and NaN 3 ( 1 O 2 scavenger) was added separately to the reaction medium and placed under N 2 atmosphere (to prevent the generation of superoxide radicals).…”

Precise Tuning of SiO2 Thickness in SiO2@Sr0.4Ti0.4Mg0.2Fe2O4.4 Core–Shell Nanocomposites for Augmenting Photocatalytic and Antibacterial Activity

“…However, ultraviolet light has higher energy, so electron–hole separation and their recombination are competitive. This led to lower photocatalytic activity under ultraviolet light. , At pH 7.0, the negative surface of the SF-4 nanocomposite, as observed from zero-point charge (pH zpc ) (Figure S5), showed a higher affinity for tetracycline hydrochloride. Figure S6 shows the poor self-degradation ability of tetracycline hydrochloride in the absence of a photocatalyst.…”

Development of Transition Metal Incorporated Bismuth‐Based Oxide Semiconductors as Potential Candidates for Solar Assisted Water Splitting Applications

“…In the early 70's scientist Fujishima and Honda first demonstrated TiO 2 as an outstanding photocatalyst to achieve solar-assisted water splitting reaction [6] and later, various investigations have been performed with different types of semiconductors. [7][8][9][10][11][12][13][14][15] Being an n-type semiconductor with TiO 2 has the ability and adequate potential to split the H 2 O molecule into H 2 and O 2 if a photon is absorbed during illumination when an interaction occurs with the electrolyte. [16,17] However, the performance of TiO 2 is relatively poor due to its wide band gap energy (~3.2 eV) and is not being suitable for all purposes.…”

“…Due to easement of fabrication, better stability and appropriate electrical properties, all inorganic semiconductors are considered as promising materials for photo‐activated water splitting reaction. In the early 70’s scientist Fujishima and Honda first demonstrated TiO 2 as an outstanding photocatalyst to achieve solar‐assisted water splitting reaction [6] and later, various investigations have been performed with different types of semiconductors [7–15] . Being an n‐type semiconductor with TiO 2 has the ability and adequate potential to split the H 2 O molecule into H 2 and O 2 if a photon is absorbed during illumination when an interaction occurs with the electrolyte [16,17] .…”