Z-scheme Heterojunction Research Articles

Piezoelectric field accelerating charge transfer in Z-scheme heterojunction 2D-KNbO3/1D-CdS for efficient piezo-photocatalytic H2 evolution and TCH degradation

The piezo-phototronic effect utilizes the piezoelectric polarization field to tune the photogenerated carrier separation and transport performance in heterojunctions, which portrays a promising strategy for addressing energy shortage and environmental pollutants. Herein, a novel Z-scheme piezoelectric semiconductor heterojunction, 2D-KNbO3/1D-CdS-x (KNCS-x), was fabricated using hydrothermal and solvothermal methods, resulting in enhanced redox capacity. Under the simultaneous light and strain, KNCS-15 exhibits the highest piezo-photocatalytic activity, with degradation rates of tetracycline hydrochloride degradation rate constant, H2O2 as well as H2 production rates being 1.806 × 10−2s−1, 45.56 mM·h−1·g−1 and 8.87 mmol·h−1·g−1, respectively, which are 1.4, 2.4 and 1.9 times of photocatalysis alone, and 9.8, 9.2 and 9.8 times of piezocatalysis alone. DFT calculations, EPR and PALS indicate that the Z-scheme structure realizes effective separation of electron-hole pairs with strong redox ability and a higher carrier concentration. The enhanced catalytic activity is attributed to the introduction of piezoelectric potential, which facilitates improved spatial separation of electrons with high reduction and holes with high oxidation potential.

Green synthesis of novel Z-scheme SnS2/HAp nanocomposite using Ocimum tenuiflorum leaf extract and investigation of its photocatalytic activity.

The present study focuses on the green synthesis of a novel Z-scheme SnS₂/HAp photocatalyst using Ocimum tenuiflorum (tulsi) leaf extract as a stabilizing agent. This approach not only emphasizes sustainability but also adds value to waste by extracting hydroxyapatite (HAp) from Labeo rohita fish scales, addressing the challenge of their disposal. The synthesized photocatalyst was thoroughly characterized using a range of analytical techniques to evaluate its crystal structure, optical properties, morphology, and elemental composition. The photocatalytic activity of the SnS₂/HAp composite was assessed through the degradation of gentian violet (GV) dye, a representative organic pollutant. Various reaction parameters were optimized to enhance the degradation efficiency, and the photocatalyst's performance was further tested across different water matrices. Under optimal conditions, the SnS₂/HAp photocatalyst achieved a maximum photodegradation efficiency of 97.49% with a rate constant of 0.0494min- 1 for GV dye. Additionally, it exhibited an efficiency greater than 70% against other emerging pollutants via advanced oxidation processes (AOP). The enhanced photocatalytic activity was attributed to the formation of a Z-Scheme heterojunction between SnS2 and HAp, which enhanced the charge separation efficiency and delayed the charge recombination. The study also demonstrated the photocatalyst's remarkable reusability, maintaining high performance over five cycles and across various water environments. This highlights its potential as a sustainable solution for the removal of organic pollutants from aqueous streams. Finally, a Z-scheme electron transport mechanism is proposed to explain the photodegradation process of GV dye using the SnS₂/HAp photocatalyst.

Efficient photocatalytic degradation of microplastics by constructing a novel Z-scheme Fe-doped BiO2−x/BiOI heterojunction with full-spectrum response: Mechanistic insights and theory calculations

Recently, microplastics (MPs) have garnered significant attention as a challenging emerging pollutant to address. Here, a full-spectrum light-driven Fe-doping BiO2−x/BiOI (FBI) Z-scheme heterojunction was constructed for efficiently degrading MPs in waters. Compared with BiO2−x, Fe doping BiO2−x, and BiOI, the optimal photocatalyst (40-FBI) can cause deep cracks in the polyethylene terephthalate (PET) within 10 h under the irradiation of full-spectrum light. Meanwhile, FT-IR characterization revealed that the absorption peak intensities of the C-O group, CO group, -CH stretching vibration, and -OH group on the MPs surface gradually increased with degradation time. A series of experiments and theory calculations revealed that the introduction of Fe creates impurity levels, accelerating the separation of photo-generated carriers and reducing the work function of BiO2−x, thereby enhancing the transport of photo-generated carriers between Z-scheme heterojunctions. This study offers a valuable idea for designing an efficient photocatalyst by simultaneously introducing ion doping and constructing heterojunctions for enhancing MPs degradation.

CoFe2O4/carbon nitride Z-scheme heterojunction photocatalytic PMS activation for efficient tetracycline degradation: Accelerated electron transfer

The escalating consumption of antibiotics and their subsequent discharge into the water supply is a matter of significant concern. This study presents an innovative visible light (VL) activated peroxymonosulfate (PMS) system for efficient degradation of the targeted antibiotic tetracycline (TC). CoFe2O4/carbon nitride (CFO/CN) Z-scheme heterojunctions were designed and synthesized through a simple co-precipitation and calcination strategy. Surface and analytical techniques were employed to comprehensively characterize the prepared CFO/CN, demonstrating its enhanced efficiency in separating photoinduced charge carriers. CFO/CN exhibited a 27-fold enhancement in TC degradation rate constants with PMS under VL. The effects of various factors including catalyst dosage, PMS concentration, initial pH, and content of CFO on TC degradation efficiency were investigated. Reactive species quenching and EPR measurements revealed the main contribution of superoxide radicals (•O2−) made to TC degradation. TC degradation pathways were proposed based on oxidized product analysis. The assessment of acute toxicity demonstrated the reduced toxicity of the formed intermediates. A plausible mechanism for TC degradation over CFO/CN-PMS-VL was discussed. This work provides a comprehensive guide for heterojunction photocatalytic activation of PMS for efficient micropollutant degradation.

Z-scheme H-PDI supermolecule/NH2-MIL-101(Fe) for enhanced malathion degradation: Mechanism, pathway, and toxicity assessment

Malathion (MA) is a widely used organophosphorus pesticide globally. Developing efficient photocatalysts is crucial for eliminating MA pollution in water by photocatalytic technology. This study focuses on preparing a series of H-PDI supermolecule/NH2-MIL-101(Fe) (PM) materials by amidating NH2-MIL-101(Fe) with the more stable H-PDI supermolecule, forming a covalent OC–NH bond. Among these materials, 40 %PM (indicating a mass percentage content of 40 % H-PDI supermolecule in PM) exhibited the best performance for degradation of MA. Under simulated sunlight irradiation of a 10 mg·L1 MA solution for 180 min, the reaction rate constants of 40 %PM were 5.95 times and 3.13 times higher than those of NH2-MIL-101(Fe) and H-PDI supermolecule, respectively. The enhanced performance is attributed to the formation of Z-scheme heterojunctions in the 40 %PM composite lead to fast separation of photogenerated e− and h+. Combining the results of HPLC-MS with Fukui Function, the HOMO, LUMO, and pathway of degradation of MA attracted by 1O2, •OH, and h+ were speculated. The pathway involves oxidation, demethylation, P-S bond breakage, decarboxylation, and final conversion to some inorganic molecules. The toxicity of the degradation byproducts were lower than that of MA estimated by Toxicity Estimation Software Tool.

Heterointerface engineering in mesoporous g-C3N4@MnFe2O4 photocatalysts for superior hydrogen (H2) evolution

Surfaces and interfaces play a pivotal role in heterostructures-based photocatalysts, which regulate the transfer, separation, and migration of photogenerated charge carriers. In this study, p-type MnFe2O4 nanoparticles (NPs) with complementary band structures were purposefully integrated with n-type porous g-C3N4 nanosheets (NSs) through precise interface engineering. The synergies in the g-C3N4@MnFe2O4 nanocomposites (NCs), leading to performance enhancement and functionalities, arise from their optimized mass fractions within the composite. The heterojunction interface formed in NCs possesses uniformly distributed mesopores (<4 nm), abundant active sites, and a high specific surface area (116 m2/g). Mesoporous heterojunctions improve photocatalytic activity by promoting the transfer of photogenerated electrons and holes to the photocatalyst surface. Notably, the optimized NCs, containing 20 wt% MnFe2O4, display the highest hydrogen evolution rate of 3.17 mmol g⁻¹ h⁻¹ (with methanol) and 5.77 mmol g⁻¹ h⁻¹ (with triethanolamine), which is many folds higher than bare MnFe2O4 and porous g-C3N4, using 1.0 wt.% of Pt as co-catalyst. The enhanced performance is corroborated by the efficient separation of photoinduced charge carriers, facilitated by an induced internal electric field arising from the Fermi level differences between the semiconductors. This study provides new insights into the advantages of designing and constructing mesoporous Z-scheme heterojunction photocatalysts for hydrogen evolution.

A novel 0D/3D Z-Scheme heterojunction ZnS/MIL-88(A) with significantly boosted photocatalytic activity toward tetracycline

Coupling two different photocatalytic materials to construct a heterojunction is a preferable strategy for obtaining the composite photocatalyst with high activity. Herein, a novel 0D/3D Z-scheme heterostructure ZnS/MIL-88(A) was constructed by anchoring 0D ZnS nanoparticles on the surface of the 3D MIL-88(A). The prepared ZnS/MIL-88(A) was characterized by using FT-IR, XRD, SEM, UV–vis and XPS. The photodegradation of tetracycline (TC) was conducted under the irradiation of visible light to evaluate the photocatalytic performance of ZnS/MIL-88(A). The creation of the Z-scheme heterostructure between ZnS and MIL-88(A) enables ZnS/MIL-88(A) to exhibit excellent visible-light absorption ability and dramatically boost separation and transfer of the photo-induced charge carriers. Compared with MIL-88(A), ZnS/MIL-88(A) shows prominently enhanced photocatalytic activity toward tetracycline, achieving a TC degradation rate of 94 %. The highest photodegradation rate constant (0.02083 min−1) of TC by ZnS/MIL-88(A) is 7.77 and 12.33 folds as large as those by MIL-88(A) and ZnS, respectively. After five cycles of reuse, ZnS/MIL-88(A) shows only a slightly decreased TC removal rate, presenting excellent photo-stability. Furthermore, the Z-scheme interfacial charge migration mode and the photocatalytic mechanism of ZnS/MIL-88(A) were discussed according to the band position as well as the identification result of the active species. The radicals ·O2− and ·OH generated in photocatalysis serve as major reactive species to decompose TC. This work provides a new way for designing efficient composite photocatalysts.

Critical trigger of self-assembled bimetallic Fe/Mn-MOF with SnS2 heterojunctions by persulfate activation for efficient tetracyclines photodegradation

Developing advanced strategies, including exposing active site centers, regulating coordination environments, controlling crystallographic facets, optimizing electronic structures and constructing defects for enhancing photocatalytic performance is of great significance to improving the ecosystem. In this study, a novel self-assembled bimetallic Fe/Mn-MOF with SnS2 Z-scheme heterojunction photocatalyst was designed using a facile multistep solvothermal method. Benefiting from the interfacial heterojunction synergistic effect, the photocatalysts exhibited an outstanding catalytic performance. Nearly 91.4% efficiency of tetracyclines was degraded within 80 min through the assistance of a persulfate-based advanced oxidation process. DFT calculations utilizing the Fukui index identified the sites vulnerable to attack by the active species. As demonstrated by the trapping experiments and electron spin resonance (ESR), the involved oxygen-active species (•O2− and 1O2) facilitated the rapid degradation of tetracycline. The degradation pathways were further guided in the elucidation of the rationale mechanism and the toxicity of derived intermediates was revealed. This work opens a new strategy for the rational design of bimetallic photocatalysts, emphasizing interface-modulated heterojunctions for efficient solar energy conversion.

Synthesis of a novel flower-like Bi4Ti3O12/AgI Z-type heterojunction for efficient photocatalytic removal of tetracycline antibiotic and RhB

Novel Flowerlike Bi4Ti3O12/AgI (BTO/AgI) Z-type heterojunctions were fabricated via a straightforward in-situ precipitation method. Notably, BTO/AgI exhibited significantly improved photodegradation efficiency for tetracycline (TC) and Rhodamine B (RhB). The rate constants for RhB and TC photodegradation were approximately 20.8 and 2.9 times higher than those of BTO alone, respectively. Furthermore, the photocatalytic efficiency of the BTO/AgI heterojunction is 1.4 times higher than that of the mixture of the two individual photocatalysts, indicating a robust interaction between BTO and AgI. This enhancement in photocatalytic performance was mainly attributed to the effective separation of photogenerated carriers facilitated by the Z-scheme heterojunction, which can be demonstrated by the highest photocurrent density (∼0.307 μA·cm−2) of BTO/AgI, surpassing BTO (∼0.073 μA·cm−2) and AgI (∼0.161 μA·cm−2) by approximately 4.12 and 1.91 times, respectively. Furthermore, three plausible photodegradation pathways of tetracycline were proposed. This study introduces a novel approach for designing and synthesizing high-efficiency Z-scheme photocatalysts for the degradation of TC and RhB in wastewater.

SnIn4S8/FeNi2P Z-scheme heterojunction hollow nanorods for photocatalytic hydrogen production

Climate change and natural disasters have stimulated the exploration of renewable energy, photocatalytic hydrogen production utilizing solar energy is considered an effective way. In this study, hollow FeNi2-MIL-88 nanorods were synthesized by the hydrothermal method, and then FeNi2P was obtained by gas phase phosphorization. Finally, SnIn4S8 was utilized to coat the surface of FeNi2P through an in-situ growth method to obtain rod-like SnIn4S8/FeNi2P. The results showed that the hydrogen production of SnIn4S8/FeNi2P reached 18083.93 μmol/g within 3 h. And SnIn4S8/FeNi2P showed good stability. The photocurrent response spectra and electrochemical impedance spectra confirmed that SnIn4S8/FeNi2P had good carrier conductivity and effectively inhibited the reorganization of photogenerated carriers. The modification of SnIn4S8 enabled the construction of a Z-scheme heterojunction between SnIn4S8 and FeNi2P. It provided more active sites and promoted the separation of photogenerated carriers, ultimately improving the hydrogen production performance of the SnIn4S8/FeNi2P photocatalyst. It would offer essential insights into the design and development of efficient MOFs-derived photocatalysts.

Z-scheme InVO4/ZnFe2O4 heterojunction for efficient photocatalytic nitrogen fixation

Given outstanding light absorption and utilization capabilities, narrow-bandgap semiconductors receive intensive interests in the photocatalysis field. However, the narrow bandgap is a double-edged sword, with the non-negligible charge carrier recombination and hinderance of redox reactions due to the limited redox capability. The construction of Z-scheme heterojunctions could address the aforementioned issues. In this work, we selected two band-matched narrow-bandgap semiconductor catalysts (InVO4 and ZnFe2O4) for the construction of a Z-scheme heterojunction. Compared with pure InVO4 and pure ZnFe2O4, the as-obtained InVO4/ZnFe2O4 Z-scheme heterojunction exhibited improved light harvesting capability and enhanced photogenerated electron-hole pair separation rate. The regulated energy band structure of as-formed InVO4/ZnFe2O4 Z-scheme heterojunction could accelerate the spatial separation of photogenerated electrons and holes, reduce the recombination probability, and provide sufficient electrons to participate in the nitrogen reduction, ultimately significantly promoting photocatalytic activity. Benefiting from above improvements, the NH3 yield of InVO4/ZnFe2O4 for photocatalytic nitrogen fixation was up to 453.37 μmol/gcat/h, which was about 17.7 times and 62.9 times higher than that of pure InVO4 and ZnFe2O4 samples, respectively. This study gives a promising guidance to the facile design and utilization of Z-scheme heterojunction composed of narrow-bandgap semiconductors.

Constructing a Z-scheme heterojunction of oxygen-deficient WO3-x and g-C3N4 for superior photocatalytic evolution of H2

Semiconductor-based photocatalytic water splitting enables the conversion of abundant solar energy to green and renewable hydrogen energy. Graphitic carbon nitride (g-C3N4) is synthesized using a straightforward method, demonstrating stable physicochemical properties and possessing an optimal bandgap, thus positioning it as a promising photocatalyst in the realm of environmental sustainability. Oxygen vacancies are extensively employed to modulate light absorption and surface properties of metal-oxide semiconductors. In this study, g-C3N4 nanosheets were coupled with oxygen-deficient tungsten trioxide (WO3-x) to form heterojunction photocatalysts (X-WOCN). Comprehensive material characterization results demonstrated that the constructed heterojunction extended the visible light absorption range, improved photogenerated electron-hole separation efficiency, and thus augmented photocatalytic activity. Notably, the optimum hydrogen evolution rate of 6%-WOCN was enhanced by 5.4-fold compared to that of g-C3N4. Furthermore, we propose a Z-scheme heterojunction charge separation mechanism mediated by oxygen defects and support this mechanism through detection of surface-active substances •O2− and •OH. This study offers novel propositions into the function of oxygen defects in facilitating charge separation within Z-scheme heterojunction.

Synthesis of a novel NiCo-LDH/Bi2WO6 Z-scheme heterojunction composite for photocatalytic degradation of tetracycline

This article aims at preparing of Z-scheme heterojunction NiCo-LDH/Bi2WO6 (LDH: layered double hydroxides) via a solvothermal technique, addressing the rapid recombination of electron-hole pairs caused by the narrow bandgap of Bi2WO6. Successful loading of NiCo-LDH onto Bi2WO6 was confirmed through various characterization techniques, assessing the composite's crystal structure, morphological traits, and performance. Notably, the NiCo-LDH/Bi2WO6 composite exhibited excellent photocatalytic performance in the degradation of tetracycline (TC), achieving an optimal reaction rate of 0.03 min−1, which is 4.8 times faster than that of Bi2WO6 alone. The findings demonstrate that the formation of the heterojunction structure facilitated the separation of photogenerated electron-hole pairs by reducing recombination in monomers. Free radical trapping experiments showcased that the decomposition of TC is primarily driven by h+ and ∙O2−. Additionally, liquid chromatography-mass spectrometry analysis identified the degradation products of TC and suggested two potential degradation pathways. The present research provides a novel approach for preparing LDH photocatalytic materials using NiCo-LDH/Bi2WO6.

Ag QDs modified BiOCl/UiO-66-NH2 Z-scheme heterojunction for accelerated visible light-driven photocatalytic degradation of ciprofloxacin

Ag quantum dots (QDs) anchored on the surface of BiOCl/UiO-66-NH2 Z-scheme heterojunctions were synthesized and characterized by various techniques such as X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra (UV–vis DRS), electrochemical impedance spectroscopy (EIS), and photoluminescence (PL). The effects of Ag QDs loading, pH values and co-existing anions on the photocatalytic performance were comprehensively analyzed. The results concluded that the Ag QDs modified catalysts exhibited excellent photocatalytic performance for the degradation of ciprofloxacin (CIP), especially, the catalyst with 5 % Ag QDs loading (referred to as ABU-5) achieved a degradation efficiency of 72 % within 120 min and the apparent reaction rate constant was 0.00538 min−1. The outstanding performance of the ABU-5 catalyst is attributed to the introduction of Ag QDs as electron transfer bridges, improving visible light absorption and enhancing charge transfer between BiOCl and UiO-66-NH2. Free radical trapping experiments and leaching tests were carried out to determine the contribution rates of reactive species to the degradation efficiency and the concentration of Ag+ in solution after the reaction. The possible degradation pathways of CIP by ABU-5 were investigated by gas chromatography-mass spectrometry (GC-MS).

Photodynamic antibacterial activity of CoTiO3/ZnIn2S4 Z-type heterojunction and its efficient enhancement mechanism by reactive oxygen species

The Solar-powered photocatalytic antibacterial technology has received widespread attention as a safe and efficient environmental self-cleaning technology, but its application remains a challenging task. Taking inspiration from the design of heterojunction structures in photocatalytic materials, this study employed a precipitation in-situ synthesis method to successfully construct a CoTiO3/ZnIn2S4 (CTZIS) Z-scheme heterojunction with excellent photocatalytic performance by depositing layered ZnIn2S4 nanosheets in situ on a rod-shaped CoTiO3 support. After visible-light irradiation for 20 min, the CTZIS antimicrobial agent (100 μg/mL) exhibited an ultra-high bacterial inactivation rate of 99.9 %, which was 10 and 11 times higher than that of ZnIn2S4 and CoTiO3 under the same conditions, using E. coli as the study object. Meanwhile, bacteria treated with CTZIS exhibited the highest degree of cell membrane lipid peroxidation and the lowest activity of intracellular respiratory chain dehydrogenase, demonstrating excellent antibacterial performance. After testing and calculation, it was found that the excellent antibacterial activity comes from the solid gap electric field between heterojunctions, which enhances the effective spatial separation of photo-generated carriers and effectively increases the quantum yield of reactive oxygen species (ROS). The synergistic antibacterial mechanism of CTZIS from bacterial surface to bacterial interior co-damage was revealed, in which the production of • O2‐ and •OH are a key active substance in the process of bacterial oxidative stress inactivation.

Synthesis of a novel Bi19Cl3S27/Bi2MoO6 Z-type heterojunction for efficient photocatalytic removal of tetracycline antibiotic and Cr(VI): Intermediate toxicity and mechanism insight

Novel Bi19Cl3S27/Bi2MoO6 (BCS/BMO) Z-type heterojunctions were synthesized using a straightforward hydrothermal method. Benefiting from the large specific surface area (62.41 m2/g) and the effective separation of photogenerated carriers facilitated by the Z-scheme heterojunction, the BCS/BMO exhibited remarkable improved photocatalytic tetracycline degradation and Cr(VI) reduction efficiency in comparison to BCS, BMO, and their physical mixture. Specifically, the photocatalytic degradation rate constants for TC and Cr(VI) are 0.0209 and 0.0218 min-1, respectively, which are 16.08 and 15.57 times those of BCS, 1.74 and 1.31 times those of BMO, and 2.4 and 1.73 times those of the physical mixture. Additionally, based on density functional theory (DFT) calculations and empirical data, three potential photocatalytic pathways of tetracycline were presented. This study presents a novel approach for designing and synthesizing high-efficiency Z-scheme photocatalysts for the degradation of TC and the reduction of Cr(VI) in wastewater.

Fabrication of visible light responsive BaFe12O19/Ag/AgI composites with enhanced photocatalytic degradation of organic pollutants

A novel visible-light-driven (VLD) BaFe12O19/Ag/AgI photocatalysts were constructed through calcination and hydrothermal methods, in which BaFe12O19 of different mass ratios were introduced. The constructed Z-scheme heterojunction provided BaFe12O19/Ag/AgI composite catalytic with effective space carrier transport and higher redox ability. In particular, the as-prepared BaFe12O19/Ag/AgI degraded nearly 94% of 2- mercaptobenzothiazole within 30minutes of visible-light illumination, which was much superior to that of pure AgI (47%) and BaFe12O19 (3%). Moreover, BaFe12O19/Ag/AgI can be easily magnetically separated, so as to facilitate its efficient separation and recovery in practical application. Photocatalytic activity assays revealed that the as-synthesized BaFe12O19/Ag/AgI also exhibited good photodegradation capability towards Imidacloprid, Tetracycline and Carbamazepine. In particular, the complex had relatively high oxygen activation ability, and its photocatalytic H2O2 production performance was 1.29 times higher than that of the AgI monomer within 120minutes, thus realizing rapid water disinfection. Overall, the constructed efficient Z-scheme BaFe12O19/Ag/AgI photocatalysts provide a novel insight in sewage purification.

Synergistic photocatalytic activity of Bi2O3/g-C3N4/ZnO ternary heterojunction with dual Z-scheme charge transfer towards textile dye degradation

It is clear that a wide range of organic substances, including synthetic textile dyes, have the potential to negatively impact the environment. It is crucial to rationally develop highly effective photocatalysts for the degradation of such type of pollutants. In this regard, a heterostructured photocatalyst comes with enhanced charge separation and extended light absorption ability that improves photocatalytic performance. Therefore, In this study, a Bi2O3/g-C3N4/ZnO (BCNZ) ternary heterojunction photocatalyst was synthesized for the degradation of methylene blue (MB) textile dye.. Thermal polycondensation method was opted to synthesize g-C3N4, while ZnO and Bi2O3 photocatalysts were fabricated using co-precipitation method. Similarly, ternary heterojunction of BCNZ was constructed through co-precipitation method. The ternary heterojunction photocatalyst demonstrated better photodegradation ability due to dual Z-scheme charge transfer route. The dual Z-scheme heterojunction enabled the ternary heterojunction to exhibit enhanced light absorption capabilities with reduced recombination rates as well as enhanced charge separation and migration efficiency (confirmed via transient photocurrent response) that resulted in improved photocatalytic performance. The BCNZ dual Z-scheme photocatalyst displayed 92 % of degradation efficiency which was much higher than that of other (binary and pristine) photocatalysts. Scavenging tests and electron spin resonance spectroscopy revealed the significant role of the •O2−, and •OH radicals in the photodegradation of MB. Furthermore, the reusability test presented good stability and recyclability of the ternary photocatalyst with 80 % degradation efficiency after five catalytic cycles.

Magnetically separable quaternary g-C3N4/Fe3O4/AgBr/rGO nanocomposite for enhanced photocatalytic degradation of ofloxacin in water under visible light irradiation

Novel photocatalytic-magnetic hybrid quaternary nanocomposite (g-C3N4/Fe3O4/AgBr/rGO) was successfully synthesized for the first time via ultrasonication-assisted wet chemistry technique. The nanocomposite was characterized using various advanced characterization techniques and its visible photocatalytic performance was analyzed by using ofloxacin (OFL) as target pollutant. The photocatalytic degradation efficiency was 100 % under conditions (pH 6.65, 0.1 g/L nanocomposite and 10 mg/L OFL) in 5 h. The pseudo-first-order kinetic constant of g-C3N4/Fe3O4/AgBr/rGO was as high as 1.1832 h−1. Evaluation of different catalysts, catalyst dosage, initial concentrations of OFL and initial solution pH have been studied. Based on the scavenging tests, benzoquinone (BQ) significantly decreased the removal efficiency of OFL to 41.4 %, indicating that O2− served as the dominant radical involved in the reaction. More importantly, after undergoing five cycles, the g-C3N4/Fe3O4/AgBr/rGO nanocomposite demonstrated robust stability and was effectively separated from the solution through magnetic means. The remarkable performance of g-C3N4/Fe3O4/AgBr/rGO is linked to substantial utilization of visible light and facilitation of Z-scheme heterojunctions, thereby facilitating charge separation. The quaternary nanocomposite exhibits auspicious potential for effectively degrading emerging organic pollutants and has bright application forecast for practical application in wastewater treatment.

Novel environmentally-friendly 0D/3D TiO2@FeMoO4 binary composite with boosted photocatalytic performance: Structural analysis and Z-scheme interpretations

For efficient pollutant degradation under any extreme circumstances, TiO2-based photocatalyst being accessible and inexpensive will be a desirable engineering source satisfying excellent photocatalytic performance in an eco-friendly manner. Here, we report the unfolded way of designing the novel concept of Z-scheme heterojunction consisting of TiO2 and FeMoO4 via thermal techniques in which hydrothermal treatment was coupled sequentially by the calcination step. The well-aligned band structure of the developed composite, possessing numerous active sites, enhanced the separation of the generated charge carriers which in turn boosted the photocatalytic efficiency. The prepared photocatalysts were thoroughly investigated via different techniques like XRD, FTIR, XPS, SEM, TEM-EDS, Pl, UV-Vis diffuse reflectance, and Uv-Vis spectroscopy. The TiO2-8 wt.% FeMoO4 (TF 8%) photocatalyst displayed better photocatalytic performance for removing Basic Fuchsin dye (BF) in 20min than other counterparts under visible light irradiation. Furthermore, the probable photocatalytic mechanism was evidenced by XPS results and the trapping experiments. Trapping experiments revealed that •O2− and •OH radicals were the primary active species. The synthesized TF 8% photocatalyst has revealed outstanding durability after five successive recycles without change in the structural features which was confirmed by XRD analysis. This work could provide new perspectives into various environmental applications by utilizing highly efficient materials that have been strategically constructed.