Methylene Blue Degradation Research Articles

G-C3N4 coupled with GO accelerates carrier separation via high conductivity for photocatalytic MB degradation

Graphitic carbon nitride (g-C3N4) is widely utilized in photocatalysis due to its responsiveness to visible light, low cost, and non-toxicity. However, its efficiency is limited by factors such as the rapid recombination of photogenerated electron-hole pairs, slow electron transfer rates, and a limited number of active surface sites. In this study, g-C3N4 was synthesized through thermal polymerization, and varying amounts of graphene oxide (GO) were incorporated via physical blending to fabricate composite photocatalysts. The results indicated that the incorporation of GO not only increased the specific surface area and modified the pore size distribution of g-C3N4 but also affected the heptazine ring structure through chemical bonding, thereby enhancing the density of active sites. Photocatalytic degradation experiments with methylene blue (MB) indicated that g-C3N4 containing 2% GO exhibited photocatalytic activity 2.84 times greater than that of pristine g-C3N4. Kinetic simulations indicated that the Kapp value for the 2% GO-g-C3N4 composite was 0.00469min-1, which is 4.34 times higher than that of pure g-C3N4 (0.00108min-1). Furthermore, this composite maintained high photocatalytic activity after four cycles of reuse. An analysis of the photocatalytic degradation mechanism revealed that the incorporation of GO effectively promoted the separation and transfer of photogenerated electron-hole pairs, enhanced photocurrent density, and improved carrier separation efficiency. Electron spin resonance (ESR) and free radical scavenging experiments confirmed that the primary active species involved in the degradation of MB by the composite photocatalyst were ·O2- and h+. This study presents a novel approach for enhancing the photocatalytic performance of g-C3N4 by modifying its electronic structure and surface properties.

Fabrication of Zn and Ti-loaded Carbon-silica Composite Derived from Gelatin Template for the Photodegradation of Methylene Blue

Carbon-silica nanocomposites (CSNs) from gelatin as a carbon source and natural template and TEOS as a silica source have been successfully synthesized and impregnated into ZnO and TiO2 photocatalysts. The structural, morphological, and textural properties and photocatalytic activity for methylene blue degradation of TiO2/CSNs and ZnO/CSNs were investigated. XRD data revealed that TiO2/CSNs and ZnO/CSNs had different structural characteristics with similar crystallinity. FTIR spectra demonstrated the presence of Zn–O and Ti–OC bonds, respectively, at about 500-450 cm-1 and 1500 cm-1. The morphological surface exhibited stacked tubular shapes of TiO2/CSNs and ZnO/CSNs with the primary elements of Ti, Zn, Si, C, and O. The nitrogen adsorption-desorption curves revealed both micropores and mesopores of TiO2/CSNs and ZnO/CSNs where the surface area reduced due to the blocking pore after impregnation. Moreover, ZnO/CSNs verified a higher degradation percentage against methylene blue than that of TiO2/CSNs. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Synthesis and Characterization of TiO2 Thin Films Modified with Anderson-Type Polyoxometalates (Ni, Co, and Fe)

In this work, TiO2 and Anderson-type polyoxometalates (Ni, Co, and Fe) thin-film composites were fabricated. The composites were characterized by FTIR and Raman spectroscopy, diffuse reflectance, and scanning electronic microscopy. The methylene blue (MB) photocatalytic degradation on the composites under UV irradiation was studied. Spectroscopic results verified the modification of TiO2 thin films. Optical and morphological properties changed after TiO2 modification. The largest change in the optical band gap was observed for the FePOM/TiO2 system, which reported a value of 3.05 eV. The POM/TiO2 systems were more efficient in methylene blue (MB) adsorption than bare TiO2. Furthermore, the modified films were more efficient than bare TiO2 during MB photodegradation tests. The NiPOM/TiO2 and the CoPOM/TiO2 were the most efficient in the MB adsorption, reaching ~20%. The NiPOM/TiO2 and the CoPOM/TiO2 composites were the most efficient in the photodegradation process, reaching ~50% of MB removal. The stability tests indicated that composite films were moderately stable after the three performed reusability cycles. Thus, these results suggest that POM modification of TiO2 can improve the adsorption and photodegradation capacity of semiconductors.

Enhanced photocatalytic activity of V2O5/g-C3N4/ZnO nanocomposite for efficient degradation of amoxicillin, chlorpyrifos and methylene blue

Enhanced photocatalytic activity of V2O5/g-C3N4/ZnO nanocomposite for efficient degradation of amoxicillin, chlorpyrifos and methylene blue

Evaluating the Photocatalytic Activity of Green Synthesized Iron Oxide Nanoparticles

Water pollution from dyes is a major environmental challenge, demanding advanced materials for efficient degradation. In this study, we synthesized iron oxide nanoparticles (IONPs) using an aqueous extract of Senegalia catechu leaves and evaluated their photocatalytic activity in methylene blue (MB) dye degradation under sunlight irradiation. The IONPs were characterized by UV-visible spectroscopy (UV–vis), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS). XRD pattern showed a highly crystalline structure with an average crystallite size of 34.7 nm, while SEM images revealed predominantly spherical particles with uneven surface texture. Photocatalytic efficiency exceeded 80% MB dye degradation after 120 min of sunlight exposure. Optimization of catalyst dose, pH, dye concentration, and other parameters is essential for maximizing degradation efficiency. The IONPs demonstrated reusability over four degradation cycles, retaining effective photocatalytic performance. This study underscores the potential of green-synthesized IONPs as eco-friendly photocatalysts for wastewater treatment and environmental remediation.

Hierarchical TiO2 nanostructures sensitized with MoS2 nanosheets: an efficient and reusable heterojunction photocatalyst for sunlight-assisted degradation of organic dye pollutants

Abstract The present study reports the synthesis, characterization, and natural sunlight-driven photocatalytic activity of a novel heterojunction photocatalyst comprised of hierarchical rutile titanium dioxide (r-TiO2) nanostructures and 1T/2H molybdenum disulfide (MoS2)nanosheets. These components were synthesized by solvothermal methods and their effective integration was achieved by using 3- aminopropyltrimethoxysilane as coupling agent. The photocatalytic activity of r-TiO2/MoS2 nanohybrid was explored for the degradation of cationic dye methylene blue (MB), and anionic dye congo red (CR) under natural sunlight. The results reveal that the sunlight-driven photocatalytic activity of pristine r-TiO2 was drastically enhanced upon sensitization with 1T/2H MoS2 nanosheets. The nanohybrid could degrade 99% MB and 98% CR within 150 min with rate constants 25.6×10−3 and 13.2×10−3 min−1respectively. The r-TiO2/MoS2 nanohybrid retained more than 85% of its catalytic activity even after four cycles of reuse. The scavenger test revealed that holes and hydroxyl radicals are mainly responsible for the degradation of MB and CR. The facile synthesis, outstanding catalytic activity under natural sunlight, and excellent recyclability make r-TiO2/MoS2 a promising heterojunction photocatalyst for the degradation of environmental pollutants from wastewater. The present study can provide new insights towards the development of efficient, economical and sustainable photocatalysts for harnessing renewable solar energy for environmental remediation applications.

Cu-TiO2/Zeolite/PMMA Tablets for Efficient Dye Removal: A Study of Photocatalytic Water Purification

In this study, Cu-doped TiO2 combined with natural zeolite (ZT) was synthesized and applied as a fixed powder layer on poly(methyl methacrylate) (PMMA) tablets. The material’s morphology, structural, and chemical properties were characterized using high-resolution scanning electron microscopy, Raman spectroscopy, and Brunauer–Emmett–Teller analysis. The antioxidant capacity was evaluated by assessing the neutralization of hydroxyl radicals and iron (III) ions. For the first time, tablets with Cu-TiO2 and ZT deposited on PMMA as the carrier were investigated for removing two dyes, methyl orange (MO) and methylene blue (MB), from water under simulated solar (SS) and UVC irradiation. Under SS irradiation, the Cu-TiO2/PMMA and Cu-TiO2/ZT/PMMA tablets achieved about 21% degradation of MB after 240 min. This result is particularly noteworthy because SS radiation provides lower energy compared with UVC, making the process more economically efficient. Furthermore, the photocatalysts are immobilized on a stable carrier, which enhances the method’s cost-effectiveness by reducing material loss and simplifying recovery. In the presence of ZT/PMMA tablets, 69% of MB was removed by adsorption after 240 min. Additionally, we explored the mechanism of degradation, revealing that the enhanced generation of hydroxyl radicals plays a pivotal role in the effective degradation of MB. At the same time, photogenerated holes contribute to the removal of MO. The overall results suggest that the tablets obtained are a promising solution for water purification due to their effectiveness, simplicity, and low processing cost.

Enhanced photocatalytic degradation of organic pollutants by randomly oriented 2D SnS2 nanostructures

Abstract In this study, we present a bottom-up solvothermal technique using tin tetrachloride pentahydrate (SnCl4.5H2O) and thioacetamide as precursors to synthesize SnS2 nanostructures. Different solvents including isopropyl alcohol, ethanol, and ethylene glycol were used in the reaction to enhance the photodegradation efficiency of organic pollutants, Methylene Blue (MB), and Tetracycline (TC) in an aqueous medium under simulated solar light irradiation. The SnS2 nanostructures synthesized with these solvents were characterized using various structural, morphological, and optical techniques, including XRD, RAMAN, FESEM, XPS, UV–Vis, and Brunauer–Emmett–Teller analysis. The choice of solvent was found to significantly affect the structural, morphological, and optical properties of the SnS2 nanostructures. Notably, the sample synthesized with ethanol as the solvent displayed a unique morphology, enhanced light-harvesting ability, efficient charge carrier separation, and a larger specific surface area, all of which contributed to its superior photocatalytic activity. This sample achieved 99.9% degradation of MB and 95% degradation of TC within 20 and 40 minutes, respectively. The kinetic analysis revealed maximum rate constant (k) values of 0.15242 min-1 for MB and 0.06095 min-1 for TC, as determined by the pseudo-first-order kinetic model. We also discuss the plausible mechanism involving visible light-induced electron-hole pairs that generate reactive species, leading to the mineralization of dyes into H2O, CO2, and other gaseous products. The synthesized SnS2 nanostructures demonstrate significant potential for enhanced photocatalytic activity in organic pollutant degradation, underscoring their promise in addressing water pollution challenges.

Underwater superoleophobic and underoil superhydrophobic PDA/Na2SiO3/N-TiO2coated mesh for selective oil/water separation and photocatalytic degradation of methylene blue

Underwater superoleophobic and underoil superhydrophobic PDA/Na2SiO3/N-TiO2coated mesh for selective oil/water separation and photocatalytic degradation of methylene blue

Construction of (001)-TiO2/g-C3N4 heterojunction for enhanced photocatalytic degradation of methylene blue

Construction of (001)-TiO2/g-C3N4 heterojunction for enhanced photocatalytic degradation of methylene blue

A study on the influence of metal Ag, Cu, and Fe doping on the morphological, structural, and photocatalytic activity of TiO2 nanostructures

Metal-doped TiO2 nanoparticles (NPs) were elaborated by a sol–gel method using n-butoxide of titanium (IV) as precursors. The resulting NPs were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman spectroscopy, and FTIR analysis. The SEM study shows the formation of a spheres-like structure. The EDX analysis proves the presence of Ag, Fe, and Cu on the doped TiO2 NPs. XRD and Raman spectroscopy analysis show that the doping inhibited the phase transformation and stabilized the anatase phase. The photocatalytic activity of prepared TiO2 NPs was evaluated in methylene blue (MB) photodegradation under UV irradiation. The results reveal that the doped TiO2 NPs were more efficient than undoped TiO2 NPs in the degradation of MB. The Cu-doped TiO2 NPs were found to be more efficient in this reaction with a degradation efficiency of about 92.31 % and a kinetic rate constant of about 10−2 min−1. The studies of the reactive species show that the holes are the main reactive species responsible for the photocatalytic oxidation of MB. Furthermore, the reusability studies showed that the photocatalysts are globally stable for the photodegradation of MB.

Magnetic and visible light-induced novel green synthesized magnetic Co3O4 photocatalysts via sunflower seed meal extract for anionic and cationic dye removal by adsorption assisted photocatalytic degradation

This study was aimed at the preparation of m-Co3O4 NPs (magnetic Co3O4 nanoparticles) from sunflower seed meal (SFSM) which is the waste of sunflower seed oil factories, and their application as a photocatalyst for the adsorption assistant photocatalysis degradation of methylene blue (MB), and direct yellow-50 (DY-50) under the visible irradiations. Also, the photocatalytic performance of m-Co3O4 NPs was evaluated in synthetic wastewater. The produced m-Co3O4 NPs were ferromagnetic with a saturation magnetization value of 4.3 emu g−1 and the degradation of cationic MB and anionic DY-50 dyes by 100% and 93% in 20 min and 35 min, respectively, by adsorption-assisted photocatalytic process under visible light was achieved. The reactions were found to be pseudo-second-order equation for the adsorption-assisted photocatalytic process for both dyes. The photocatalytic activity of m-Co3O4 NPs decreased slightly even after five repeated cycles. These results show that the m-Co3O4 NPs can be used successfully in dye treatment in wastewater with their adsorption-assisted photocatalytic properties, activation by visible light, magnetic separability, and low-cost production.

Enhanced methylene blue degradation and miniralization through activated persulfate coupled with magnetic field

In this work, for the first time, the effectiveness of the degradation and mineralization process of methylene blue) MB) was investigated using activated persulfate (PS) with a magnetic field. The effect of various operating parameters, including pH, PS (5–20 mg/L), intensity of the magnetic field (1–4 A), initial concentration of methylene blue dye (25–100 mg/L), and contact time (30–120 min), was evaluated. Process optimization was conducted via the Taguchi model, and the optimal values of these factors were found to be pH = 5, PS = 10 mg/L, MFs = 4 A, reaction time = 30 min, and the initial concentration of methylene blue dye = 50 mg/L. Under optimal conditions, the methylene blue removal efficiency and TOC destruction efficiency reached 91.8% and 88%, respectively. The kinetics of the process followed pseudo-second order (R2 = 0.9723). According to the promising results of the research, the efficiency of dye purification using a magnetic field has increased by about three times compared to the state without this factor. It can be suggested that this system be used as a wastewater treatment process for the textile industry to reduce the toxicity of wastewater and total organic carbon (TOC).

Plasmonic ZnO-Au Nanocomposites: A Synergistic Approach to Enhanced Photocatalytic Activity through Nonthermal Plasma-Assisted Synthesis

A novel and efficient method for synthesizing Au-decorated ZnO nanoparticles (NPs) with enhanced photocatalytic activity is presented. The synthesis involves a two-step process: hydrothermal preparation of ZnO NPs followed by nonthermal plasma-assisted deposition of Au nanoparticles on their surface. Comprehensive characterization of the ZnO and ZnO–Au NPs was carried out using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Optical properties were evaluated via UV-Vis absorption and fluorescence measurements. The synthesized ZnO NPs displayed a hexagonal wurtzite structure, and the successful deposition of Au NPs was confirmed by TEM and XPS analysis, along with Raman and fluorescence data showing the quenching effect caused by Au. The incorporation of Au nanoparticles led to the appearance of localized surface plasmon resonance (LSPR) at 540 nm, enhancing visible light absorption and improving photocatalytic performance. Notably, the methylene blue (MB) degradation efficiency increased from 78% with pure ZnO NPs to 91.6% with ZnO–Au NPs under UV-Vis irradiation, demonstrating superior photocatalytic activity. This study introduces a simple and scalable method for synthesizing plasmonic ZnO-Au hybrid nanomaterials using plasma technology and highlights the critical role of Au NPs in enhancing photocatalytic performance by reducing electron–hole recombination.

Designed magnetic nanoparticles for ferroptosis: Release of iron ions from metal-organic frameworks modified with iron oxides

The unique chemical properties of the catalytic and biocompatible metal organic framework MIL88b allow for considering it as prooxidant agent. The authors hypothesize whether additional modification of the MIL88b with an additional iron source as Fe3O4 nanoparticles can increase both pro-oxidant activity and provide magnetic properties contributing to target delivery. The prooxidant activity of the Fe3O4-MOF was studied using electron paramagnetic resonance spectroscopy and methylene blue degradation reactions in the presence of hydrogen peroxide. To understand the reaction mechanism, the authors studied the released iron ions, as well as the surface composition using the X-ray photoelectron spectroscopy method. The addition of iron oxide leads to a more prolonged release of iron ions and the production of hydroxyl radicals within 24 h. The native MIL88b demonstrates the highest Fenton reaction rate due to "sacrificial" behavior (despite lower concentration of iron ions in the composition and on the surface compared to the modified sample) and the blocking of the active centers of MIL88b by Fe3O4 on the surface.

Nitrogen doped TIO2/g-C3N4 nanocatalyst for photodegradation of methylene blue dye

In this study, the ethanol dispersion procedure was implemented to prepare the g-C3N4/N–TiO2 nanocatalyst structure. Sol-gel synthesis is utilized for synthesizing N–TiO2 and g-C3N4 via urea thermal decomposition. Physicochemical properties of produced photocatalysts were revealed using PL imaging, UV–vis DRS, XRD, FTIR, SEM, BET, and TEM. Evaluation of photocatalytic activity of synthetic photocatalysts by exposure to sunlight and degradation of methylene blue (MB) dye. g-C3N4/N–TiO2 NCs showed excellent photocatalytic activity, reaching 96 % MB degradation efficiency in 80 min. g-C3N4 and N–TiO2 doped form a nanocomposite structure that increases photocatalytic activity, affecting charge separation performance and service life. The system also exhibits the ability to collect visible and ultraviolet light. Even after four consecutive cycles, the efficiency of the MB is still above 85 %. Capture experiments showed that the decomposition of MB was mainly caused by h+ and O22− radicals. The results of kinetic investigations indicate that the degradation rate of g-C3N4/N–TiO2 nanocomposites surpasses that of N–TiO2 nanoparticles.

Solar driven highly efficient photocatalyst based on Dy2O3 nanorods deposited on reduced graphene oxide nanocomposite for methylene blue dye degradation.

In recent years, the demand for rare earth elements has surged due to their unique characteristics and diverse applications. This investigation focuses on utilizing the rare earth element dysprosium oxide (Dy2O3) for the photocatalytic oxidation of model pollutants under solar light irradiation. A novel RGO-Dy2O3 nanocomposite photocatalyst was developed using a solvothermal approach, Dy2O3 nanorods uniformly deposited onto reduced graphene oxide (RGO) nanosheets. Comprehensive characterization techniques, including Brunner-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), Raman spectroscopy, high resolution - transmittance electron microscopy (HR-TEM), field emission-electron scanning microscopy (FE-SEM), atomic force microscopy (AFM), electron paramagnetic resonance spectroscopy (EPR), photoluminescence spectroscopy (PL), and electrochemical impedance spectroscopy EIS techniques. The UV-visible diffusive reflectance spectroscopy (UV-Vis-DRS) studies revealed a band gap energy of 3.18eV and a specific surface area of 114 m2/g for the fabricated RGO-Dy2O3 nanocomposite. The RGO-Dy2O3 nanocomposite demonstrated a high photocatalytic degradation efficiency of 98.1% at neutral pH for methylene blue (MB) dye for the dye concentration of 10ppm. The remarkable photocatalytic performance was achieved within 60min under solar light irradiation. Reusability tests demonstrated stability, maintaining over 90% photocatalytic efficiency after three cycles. The EPR spectra and quenching experiments confirmed that photogenerated hydroxyl radicals significantly influence the photodegradation processes. The RGO-Dy2O3 nanocomposite photocatalyst, with its green, easy preparation process and recycling capabilities, presents an ideal choice for various applications. It offers a viable alternative for the photocatalytic degradation of organic dyes in real wastewater, contributing to sustainable environmental remediation.

Alginate/CuO-gC3N4 composite: a novel, reusable, non-toxic photocatalyst for methylene blue degradation.

Increasing industrial contamination necessitates development of sustainable water treatment solutions. Photocatalysis is a green technology utilizing light-activated materials (photocatalysts), which can degrade pollutants into harmless by-products. It is an emergent need to develop a photocatalyst that presents a significant advancement for sustainable water treatment and non-toxic to the environment. This study investigates the photocatalytic activity and in vitro cytotoxicity of a novel hybrid material comprising of alginate, copper oxide (CuO) and graphitic carbon nitride (gC3N4) for methylene blue (MB) degradation. The hybrid material was synthesized by a two-step process: (i) doping of CuO on gC3N4 through co-precipitation method formed CuO-gC3N4 (CG) and (ii) incorporation of CG in the calcium alginate (A) by ionotropic gelation method that is named as ACG. The characteristic features of the synthesized A, CG and ACG were studied using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The optical characteristic of A, CG and ACG was studied using UV-diffuse reflectance spectroscopy (UV-DRS). The morphology and elemental composition of ACG was evaluated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). To assess the environmental impact of ACG, a two-step approach was employed. First, the photocatalytic activity of ACG under UV-visible light (UV-vis) irradiation for MB degradation was evaluated. ACG exhibited photocatalytic activity by achieving 86.26% of degradation efficiency for MB within 60min. Second, the in vitro cytotoxicity of ACG, MB and MB degraded products towards tilapia gill cell lines were assessed. By comparing the toxicity of the MB and the secondary products, it is concluded that the overall process leads to a sustainable outcome.

Semiconductor Nanoporous Anodic Alumina Photonic Crystals as a Model Photoelectrocatalytic Platform for Solar Light‐Driven Reactions

In this study, nanoporous anodic alumina distributed‐Bragg reflectors (NAA–DBRs) functionalized with tungsten trioxide (WO3) are used as prototype photoelectrocatalysts (PEC) for harnessing the slow photon effect to maximize photon‐to‐electron conversion efficiency under UV–visible–NIR illumination. NAA–DBR structures are structurally engineered by anodization, where their characteristic photonic stopband is precisely tuned along specific positions of the UV–visible spectrum. Subsequent atomic layer deposition is employed to coat the inner surface of these porous structures with WO3 semiconductor layers. Upon the application of overpotential bias, these platforms reveal excellent electron–hole pair separation to boost photoelectrocatalytic reactions. Photoelectrochemical degradation of methylene blue is used as a model reaction to elucidate enhancements associated with structural and optoelectronic arrangements. Notably, precise spectral alignment between the photonic stopband's red edge and the absorbance band of methylene blue enhances the degradation performance through the slow photon effect. Applying an overpotential bias further improves the photodegradation performance through efficient charge separation. These systems outperform comparable structures in this model reaction, achieving a maximum kinetic rate of 13.7 ± 2.0 h−1. The findings create new opportunities to develop high‐performing PEC technologies harnessing light–matter interactions.

Synthesis and characterization of zinc-doped hematite nanoparticles for photocatalytic applications and their electronic structure studies by density functional theory

Hematite nanoparticles doped with 1, 3 and 5 % Zn (all % are in molar) were prepared using mechanical alloying. Morphological and phase structure studies using scanning electron microscopy and X-ray diffraction showed nanoparticles possessing a semi-spherical shape and particle size of <50 nm crystallized in rhombohedral structure. The lattice parameters of hematite increased upon Zn doping. The energy-dispersive X-ray and Fourier-transform infrared results demonstrated that Zn was successfully incorporated. The optical behavior of nanoparticles was examined by UV–Vis diffuse reflectance spectroscopy and revealed that Zn doping increased the absorption intensity in the visible light region and decreased the band gap from 1.95 (hematite) to 1.83 eV (3 % Zn). Methylene blue dye degradation by the 3 % Zn sample proved doubling of the photocatalytic activity due to electronic structure modification upon Zn doping. First principles studies using density functional theory performed to investigate the effect of Zn on the electronic band structure of hematite showed that Zn doping caused band gap reduction, causing formation of new energy states, mainly above the valence band. Eventually, the enhancement of Urbach energy and reduction of effective mass, respectively accountable for increasing the relaxation time and mobility of charge carriers, were considered the two main mechanisms regarding the increased photocatalytic behavior of hematite by Zn doping.