Separation Efficiency Of Charge Carriers Research Articles

Regulation of Charge Transfer Pathway in Ag-ZnIn2S4 Nanowires for Visible Photodynamic Therapy on Candida Albicans Infections.

Photodynamic therapy (PDT) is receiving extensive attention as an antimicrobial strategy that does not cause drug resistance by reactive oxygen species (ROS). Herein, hierarchical Ag-ZnIn2S4 (Ag-ZIS) core-shell nanowires are synthesized by in situ Metal-Organic Framework derived method for efficient PDT of Candida albicans (C. albicans). The core-shell structure enables spatial synergy strategy to regulate the charge transfer pathway under visible light excitation, in which the Ag nanowires are like the highway for the photogenerated electrons. The enhanced charge carrier separation efficiency greatly increased the chances for the generation of ROS. As expected, the optimized Ag-ZIS nanowires exhibit excellent performance for inactivation of C. albicans under visible light irradiation (λ ≥ 420 nm, 15 min), and the effective sterilization concentration is as high as 107CFU mL-1. Moreover, in vivo infection experiments suggested that the PDT effect of Ag-ZIS nanowires on the mouse wound healing is better than that of the clinical Ketoconazole drug. The PDT antifungal mechanism of Ag-ZIS nanowires is also investigated, and superoxide anion is found to be the predominant active species to causes C. albicans damage. This work provides a new perspective for designing novel interface structures to regulate charge transfer to achieve efficient PDT antifungal therapy.

Full-Space Electric Field in Mo-Decorated Zn2In2S5 Polarization Photocatalyst for Oriented Charge Flow and Efficient Hydrogen Production.

Integration of photocatalytic hydrogen (H2) evolution with oxidative organic synthesis presents a highly attractive strategy for the simultaneous production of clean H2 fuel and high-value chemicals. However, the sluggish dynamics of photogenerated charge carriers across the photocatalysts result in low photoconversion efficiency, hindering the wide applications of such a technology. Herein, we overcome this limitation by inducing the full-space electric field via charge polarization engineering on a Mo cluster-decorated Zn2In2S5 (Mo-Zn2In2S5) photocatalyst. Specifically, this full-space electric field arises from a cascade of the bulk electric field (BEF) and local surface electric field (LSEF), triggering the oriented migration of photogenerated electrons from [Zn-S] regions to [In-S] regions and eventually to Mo cluster sites, ensuring efficient separation of bulk and surface charge carriers. Moreover, the surface Mo clusters induce a tip enhancement effect to optimize charge transfer behavior by augmenting electrons and proton concentration around the active sites on the basal plane of Zn2In2S5. Notably, the optimized Mo1.5-Zn2In2S5 catalyst achieves exceptional H2 and benzaldehyde production rates of 34.35 and 45.31mmol gcat -1 h-1, respectively, outperforming pristine ZnIn2S4 by 3.83- and 4.15-fold. Our findings mark a significant stride in steering charge flow for enhanced photocatalytic performance. This article is protected by copyright. All rights reserved.

Regulating the Topology of Covalent Organic Frameworks for Boosting Overall H2O2 Photogeneration

AbstractPhotocatalytic oxygen reduction reactions and water oxidation reactions are extremely promising green approaches for massive H2O2 production. Nonetheless, constructing effective photocatalysts for H2O2 generation is critical and still challenging. Since the network topology has significant impacts on the electronic properties of two dimensional (2D) polymers, herein, for the first time, we regulated the H2O2 photosynthetic activity of 2D covalent organic frameworks (COFs) by topology. Through designing the linking sites of the monomers, we synthesized a pair of novel COFs with similar chemical components on the backbones but distinct topologies. Without sacrificial agents, TBD‐COF with cpt topology exhibited superior H2O2 photoproduction performance (6085 and 5448 μmol g−1 h−1 in O2 and air) than TBC‐COF with hcb topology through the O2‐O2⋅−‐H2O2, O2‐O2⋅−‐O21‐H2O2, and H2O‐H2O2 three paths. Further experimental and theoretical investigations confirmed that during the H2O2 photosynthetic process, the charge carrier separation efficiency, O2⋅− generation and conversion, and the energy barrier of the rate determination steps in the three channels, related to the formation of *OOH, *O21, and *OH, can be well tuned by the topology of COFs. The current study enlightens the fabrication of high‐performance photocatalysts for H2O2 production by topological structure modulation.

Regulating the Topology of Covalent Organic Frameworks for Boosting Overall H2O2 Photogeneration.

Photocatalytic oxygen reduction reactions and water oxidation reactions are extremely promising green approaches for massive H2O2 production. Nonetheless, constructing effective photocatalysts for H2O2 generation is critical and still challenging. Since the network topology has significant impacts on the electronic properties of two dimensional (2D) polymers, herein, for the first time, we regulated the H2O2 photosynthetic activity of 2D covalent organic frameworks (COFs) by topology. Through designing the linking sites of the monomers, we synthesized a pair of novel COFs with similar chemical components on the backbones but distinct topologies. Without sacrificial agents, TBD-COF with cpt topology exhibited superior H2O2 photoproduction performance (6085 and 5448 μmol g-1 h-1 in O2 and air) than TBC-COF with hcb topology through the O2-O2⋅--H2O2, O2-O2⋅--O2 1-H2O2, and H2O-H2O2 three paths. Further experimental and theoretical investigations confirmed that during the H2O2 photosynthetic process, the charge carrier separation efficiency, O2⋅- generation and conversion, and the energy barrier of the rate determination steps in the three channels, related to the formation of *OOH, *O2 1, and *OH, can be well tuned by the topology of COFs. The current study enlightens the fabrication of high-performance photocatalysts for H2O2 production by topological structure modulation.

Surface-Grafted Single-Atomic Pt-Nx Complex with a Precisely Regulating Coordination Sphere for Efficient Electron Acceptor-Inducing Interfacial Electron Transfer.

Based on the electron-withdrawing effect of the Pt(bpy)Cl2 molecule, a simple post-modification amide reaction was firstly used to graft it onto the surface of NH2-MIL-125, which formed a highly efficient electron acceptor that induced the conversion of the photoinduced charge migration pathway from internal BDC→TiOx migration to external BDC→PtNx migration, significantly improving the efficiency of photoinduced electron transfer and separation. Furthermore, precise control over the first coordination sphere of Pt single atoms was achieved using further post-modification with additional bipyridine to investigate the effect of Pt-Nx coordination numbers on reaction activity. The as-synthesized NML-PtN2 exhibited superior photocatalytic hydrogen evolution activity of 7.608 mmol g-1 h-1, a remarkable improvement of 225 and 2.26 times compared to pristine NH2-MIL-125 and NML-PtN4, respectively. In addition, the superior apparent quantum yield of 4.01% (390 nm) and turnover frequency of 190.3 h-1 (0.78 wt% Pt SA; 129 times compared to Pt nanoparticles/NML) revealed the high solar utilization efficiency and hydrogen evolution activity of the material. And macroscopic color changes caused by the transition of carrier migration paths was first observed. It holds profound significance for the design of MOF-Molecule catalysts with efficient charge carrier separation and precise regulation of single-atom coordination sphere.

Surface‐Grafted Single‐Atomic Pt‐Nx Complex with a Precisely Regulating Coordination Sphere for Efficient Electron Acceptor‐Inducing Interfacial Electron Transfer

Based on the electron‐withdrawing effect of the Pt(bpy)Cl2 molecule, a simple post‐modification amide reaction was firstly used to graft it onto the surface of NH2‐MIL‐125, which formed a highly efficient electron acceptor that induced the conversion of the photoinduced charge migration pathway from internal BDC→TiOx migration to external BDC→PtNx migration, significantly improving the efficiency of photoinduced electron transfer and separation. Furthermore, precise control over the first coordination sphere of Pt single atoms was achieved using further post‐modification with additional bipyridine to investigate the effect of Pt‐Nx coordination numbers on reaction activity. The as‐synthesized NML‐PtN2 exhibited superior photocatalytic hydrogen evolution activity of 7.608 mmol g−1 h−1, a remarkable improvement of 225 and 2.26 times compared to pristine NH2‐MIL‐125 and NML‐PtN4, respectively. In addition, the superior apparent quantum yield of 4.01% (390 nm) and turnover frequency of 190.3 h−1 (0.78 wt% Pt SA; 129 times compared to Pt nanoparticles/NML) revealed the high solar utilization efficiency and hydrogen evolution activity of the material. And macroscopic color changes caused by the transition of carrier migration paths was first observed. It holds profound significance for the design of MOF‐Molecule catalysts with efficient charge carrier separation and precise regulation of single‐atom coordination sphere.

Ag nanocubes-decorated ammonium hydroxide-treated carbon nitride to improve photocatalytic H2O2 production and fuel cell performance

A novel photocatalyst is designed by surface modification and cocatalyst loading of graphitic carbon nitride (g-C3N4) with ammonium hydroxide and silver nanocubes (AgNCs), respectively. The synergistic effect of the modification in the intralayer of g-C3N4 and surface plasmon resonance (SPR) bands of AgNCs significantly enhances the migration and separation efficiency of photo-induced charge carriers. A nickel mesh coated with photocatalyst and the carbon paper loaded with pristine g–C3N4–mixed iron phthalocyanine (FeIIPc) used as the photoanode and cathode, respectively, are constructed for the self-powered photoelectrochemical cell, which exhibits the maximum power density of 0.74 mW cm−2. The AHCN/AgNCs-based cell reveals approximately a 3.1-times enhancement in maximum power density compared with the pristine g–C3N4–based cell. In addition, the photocatalytically generated H2O2 (chemical energy) can be stored in water, and then used as fuel by the connection of two electrodes in the dark. After the fuel cell is operated for 12 h, the specific capacitance retention rate still maintains as high as 57.2 %, which is the greatest retention rate in comparison with the previously reported H2O2 fuel cell systems. Our work offers a feasible opinion on how to improve the visible light utilization of semiconductors by tuning the intralayer properties and loading plasmonic metal.

Photocatalytic application towards the degradation of ciprofloxacin and algae by Z-scheme 2D/3D heterojunction of Bi12O17Cl2/UiO-66-NH2

With the continuous emergence of antibiotics in natural water bodies, the crisis of water environment is becoming increasingly serious. To efficiently remove antibiotics, a novel 2D/3D Z-scheme heterojunction of Bi12O17Cl2/UiO-66-NH2 was constructed by in situ growth technology. The formation of Z-scheme heterojunction between Bi12O17Cl2 and UiO-66-NH2 not only significantly improves the transfer rate and separation efficiency of charge carriers, but also greatly prolongs the lifetime of electrons and improves their light absorption ability. Free radical capture experiments and ESR spectra display that ⋅O2− and ⋅OH radicals dominate the degradation process of ciprofloxacin. The synthesized Z-scheme heterojunction shows a high degradation rate of 83.5 % for antibiotic ciprofloxacin within 60 min, much higher than those of Bi12O17Cl2, UiO-66-NH2 monomers and many other reported photocatalysts. The heterojunction Bi12O17Cl2/UiO-66-NH2 also exhibits excellent degrading performance towards antibiotics in three actual water bodies (tap water, lake water and the effluent of domestic sewage treatment plant). Meanwhile, the as-prepared photocatalyst can effectively degrade Microcystis aeruginosa and algal toxin Microcystin-LR in surface water bodies contaminated by algae and antibiotics. The QSAR analysis indicates that the toxicities of both ciprofloxacin and its intermediates are greatly reduced. The degradation pathways of ciprofloxacin were analyzed via Density Functional Theory calculations and QSAR analysis. This study provides an excellent synthesis method of Z-scheme heterojunction for the purification of surface water bodies contaminated by algae and antibiotics via photocatalytic technology.

Photo-induced in-situ synthesis of Cu2O@C nanocomposite for efficient photocatalytic evolution of hydrogen

Cuprous oxide (Cu2O) is an ideal visible light catalyst owing to its narrow band gap, environmental benignity and abundant storage; however, the fast recombination of photogenerated charge carriers and poor stability of Cu2O has impeded its application in photocatalysis. Herein, we demonstrate that Cu2O@C nanocomposite can spontaneously evolve from a methanol aqueous solution containing cupric ions under the induction of irradiation. Compared with the traditional carbon coating method, the Cu2O@C nanocomposite obtained by the photo-induced in-situ synthesis can reserve superior original characteristics of the semiconductor under mild reaction conditions, promote the charge transfer and enhance the separation efficiency of charge carriers; in addition, the carbon shells can also effectively prevent Cu2O from photo-corrosion. As a result, the Cu2O@C nanocomposite exhibits excellent photocatalytic activity in the hydrogen evolution in comparison with the Cu2O particles; the H2 evolution rate over the Cu2O@C nanocomposite reaches 1.28 mmol/(g·h) under visible light, compared with the value of 0.065 mmol/(g·h) over Cu2O. Moreover, the Cu2O@C nanocomposite displays good cycle stability, viz., without any deactivation in the catalytic activity after five cycles.

Selective activation of dioxygen to singlet oxygen over La-Si co-doped TiO2 microspheres for photocatalytic degradation of formaldehyde

Volatile Organic Compounds (VOCs) are highly harmful to human beings and other organisms, and thus the elimination of VOCs is extremely urgent. Here, La-Si co-doped TiO2 microsphere photocatalysts, which were prepared by a hydrothermal method, exhibited high photocatalytic activity in the decomposition of formaldehyde compared with TiO2. The improved activity can be attributed to the promoted separation efficiency and density of the charge carriers, as verified by the electrochemical results in combination with density functional theory calculations. In addition, the Si dopant changed the microstructure and surface acidity, while the addition of La promoted the separation efficiency of charge carriers. More interestingly, it was found that singlet oxygen was the key species in the activation of molecular dioxygen, and it played a pivotal role in the photocatalytic decomposition of formaldehyde. This work provides a novel strategy for the selective activation of dioxygen for use in the decomposition of formaldehyde.

A facile route for decoration of hematite photoanodes by transition metal hydroxide co‐catalysts

AbstractEarth‐abundant α‐Fe2O3 (hematite) is a convincing photoanode for photoelectrochemical (PEC) water splitting; however, its intrinsic properties of inferior charge transfer and sluggish water oxidation kinetics limit its performance. Here, we report a straightforward decoration method for transition metal hydroxides to accelerate the oxygen evolution reaction (OER) of hematite photoanodes grown by electric field‐assisted liquid phase deposition (EA‐LPD). The investigations revealed that Co(OH)2 acts as a superior co‐catalyst compared with hydroxides of Mn, Fe, Co, Ni, and Zn. EA‐LPD‐grown hematite photoanode loaded with cobalt hydroxide exhibited an excellent PEC performance. A photocurrent density of 0.93 mA.cm−2 at 1.23 V versus reversible hydrogen electrode was achieved for the modified hematite, ∼3 times more than that of pristine hematite, and a cathodic shift of 100 mV for the onset potential was observed. The proposed simple and cost‐effective co‐catalyst loading strategy provides a high degree of freedom in the design of co‐catalysts with a complex chemical composition comprising transition metal oxyhydroxides and hydroxides on different photoanodes for more efficient charge carrier separation for the PEC applications.

Enhanced oxygen evolution of a new copper-based metal-organic framework through the construction of a heterogeneous structure with bismuth oxyiodide

Herein, a newly developed MOF, Cu-based on 2-amino terephthalic acid (CuATPA) is successfully prepared and utilized as a photoanode material. To achieve high-efficiency electron/hole separation and rapid catalytic kinetics, a heterojunction architecture is designed by combining CuATPA with BiOI. Scanning electron microscopy images reveal the formation of CuATPA nanoplates within the structures of BiOI nanoflakes. Electrochemical characterization demonstrates the excellent photoelectrocatalytic performance of the CuATPA-BiOI nanocomposite. Linear sweep voltammetry reveals a reduced overpotential value for the CuATPA-BiOI nanocomposite, indicating enhanced catalytic activity. Moreover, the CuATPA-BiOI photoanode displays a photo-voltage of 0.43 V compared to 0.23 and 0.24 V for the CuATPA and BiOI photoanodes, respectively, indicating a deeper band bending. The improved photoelectrochemical performance of the nanocomposite is attributed to efficient separation and transfer of photo-generated charge carriers, as evidenced by higher charge density extracted from the Mott-Schottky plot and smaller semicircle radius in the Nyquist plot.

Preparation of BiOBrxCl1‐x solid solution photocatalyst with oxygen vacancies for degradation of methyl orange under simulated sunlight

AbstractBiOBrxCl1‐x solid solution with oxygen vacancies was synthesized using a simple one‐step hydrothermal method. The sample was characterized using comprehensive characterization techniques, and the results showed that the solid solution material was successfully prepared. Adjusting the relative proportion of halogens in BiOBrxCl1‐x solid solution has a significant impact on the morphology, optical properties, and photocatalytic activity of the sample, and oxygen vacancies are introduced into the material. The presence of oxygen vacancies improves the separation efficiency of charge carriers and facilitates the activation of oxygen molecules into superoxide radicals. Among them, BiOBr0.2Cl0.8 showed flower‐like microspheres morphology and exhibited the best photocatalytic activity. After 30 min of dark adsorption and 1 h of simulated sunlight exposure, the removal rate of methyl orange (MO) was 92.5%, which was 2.38 times higher than that of pure BiOBr (38.9%) and 2.09 times higher than that of pure BiOCl (44.3%), respectively.

Nickel ion (Ni2+) doping induced formation of W18O49/W3O8 bulk homojunction for enhancing photo-assisted energy storage

The photo-assisted charging supercapacitors that integrate solar energy conversion and energy storage in one device have inspired great interests. In this work, a bulk homojunction W18O49/W3O8 was prepared through doping Ni2+ in W18O49, and was used as the active material of photoelectrodes. The Ni-doped W18O49/W3O8 photoelectrodes exhibited superior photoelectric property and excellent capacity for energy storage. The optimal WN2 photoelectrode showed a specific capacitance of 667.7 F.g−1 at current density of 4 A.g−1 under light illumination, which was 19.4% higher than that in dark. The photogenerated charge carriers and the efficient separation of charge carriers induced by homojunction could be responsible for the photo-enhanced charge storage. After cycling test, WN2 photoelectrode retained about 92% of its initial specific capacitance without irradiation, and surprising 102% of its initial specific capacitance with irradiation. The electrochemical energy storage process of WN2 photoelectrode was found to be dominated by bulk solid-state diffusion, and the mechanism analysis provided theoretical evidence for photo-assist enhanced electrochemical performance of the prepared electrodes.

A novel BiOBr/rGO photocatalysts for degradation of organic and antibiotic pollutants under visible light irradiation: Tetracycline degradation pathways, kinetics, and mechanism insight

In this study, the BiOBr/rGO nanocomposite photocatalysts are fabricated by a facile solvothermal method. The BiOBr growth on reduced graphene oxide (rGO) sheet could improve BiOBr's photocatalytic activity by increasing its adsorption ability, surface area, and charge carriers' separation efficiency. The prepared nanocomposites were characterized by XRD, Raman, FESEM, EDS, XPS, and UV–visible DRS. The BiOBr/rGO (BRG) nanocomposites showed improved photocatalytic activity for the photodegradation of Rhodamine B (RhB) dye and Tetracycline (TC) under visible light irradiation. Rhodamine B and tetracycline degradation efficiency were about 96% and 73% within 120 min under visible light irradiation. The PL analysis indicates that BiOBr/rGO nanocomposite exhibited maximum separation efficiency of photoinduced charge carriers. The trapping test confirmed that O2− and h+ are significant active photodegradation species. The GC-MS spectra detected the two plausible transformation routes of tetracycline degradation. The current work presented a low-cost and facile approach for fabricating Bi-based composites.

Constructing a type-II heterojunction of AgI/CO32−-Bi2O2CO3 for enhanced photocatalytic degradation of organic pollutants

The construction of heterojunctions is a well-established approach for enhancing the photocatalytic efficiency of semiconductor materials. To improve the photocatalytic activity of CO32−-Bi2O2CO3, AgI/CO32−-Bi2O2CO3 type-II heterojunction photocatalysts were synthesized using an electrostatic self-assembly method with varying composite ratios. The performance of AgI/CO32−-Bi2O2CO3 catalyst was investigated by photocatalytic degradation of 2-Hydroxy-1, 4-naphthoquinone and levofloxacin under a 300 W xenon lamp (λ ≥ 420 nm). The results demonstrated that the composite photocatalyst (0.5ACBOC), prepared by incorporating 0.5 mL of AgNO3 and KI, exhibited exceptional photocurrent responsiveness and efficient charge carrier separation. 0.5ACBOC displayed the highest degradation efficiency towards 2-Hydroxy-1,4-naphthoquinone (67.5%) and levofloxacin (78.0%). Free radical capture experiments and electron paramagnetic resonance (EPR) analysis revealed ·O2− as a crucial reactive species in the photodegradation process. Moreover, the photocatalytic degradation of 2-Hydroxy-1,4-naphthoquinone exhibited consistent removal efficiency even after undergoing four cycles, thereby demonstrating the excellent cycle stability of the composite catalyst. These findings highlight that AgI/CO32−-Bi2O2CO3 can be easily synthesized and holds great potential as a photocatalyst for efficient degradation of organic pollutants.

Enhanced photocatalytic CO2 reduction via single-atom Au anchored on ZnIn2S4 nanosheets

In this study, we systematically investigated the effect of single-atom gold (Au) loaded on ZnIn2S4 nanosheets on the photocatalytic reduction of carbon dioxide (CO2). Utilizing a photodeposition method, we successfully dispersed single-atom Au uniformly on the surface of ZnIn2S4 nanosheets. Under simulated sunlight irradiation, the Au-loaded catalyst demonstrated a higher yield and selectivity in the CO2 reduction reaction compared to the pure ZnIn2S4 nanosheets. Surface photovoltage testing revealed that the addition of Au significantly enhanced the separation efficiency of photo-generated charge carriers, thereby improving the photocatalytic efficiency. Density functional theory calculations indicated that the loading of single-atom Au reduced the reaction energy barrier from CO2 to CO, enhancing the selectivity of photocatalytic CO2 reduction. This research not only developed an efficient catalyst for CO2 reduction but also provided deep insights into the mechanism of single-atom catalysts in the photocatalytic CO2 reduction process through extensive experimental and theoretical analysis.

Synthesis and transformation of graphene-like structures from bamboo waste for photoelectrochemical devices

This study presents a sustainable and versatile approach to synthesize graphene-like structures from bamboo waste for application in photoelectrochemical (PEC) devices. Due to its high cellulose content, bamboo, a locally available and renewable resource, is a perfect precursor for producing graphene-like materials. The synthesis process involves bamboo waste pyrolysis, followed by treatments with different solvents: ultrapure water (UPW), NaOH, and green tea extract. Characterization techniques confirmed the successful transformation of bamboo waste into carbon-rich, graphene-like materials with varying surface properties. The electrochemical characterization showed that the graphene-like materials could transfer electrons very well with a high current response compared to charcoal as a precursor. PEC evaluations revealed their potential as photoanodes, exhibiting efficient light absorption and charge carrier separation. This research emphasizes the significance of bamboo waste as a valuable precursor for eco-friendly graphene-like materials, offering a sustainable pathway for developing efficient PEC devices and green energy technologies.

Enhanced photocatalytic performance of MXene-Modified cation-exchanged CoFe-LDH/CoFeCrO4 heterostructure for Antibiotic degradation and hydrogen production through synergistic charge dynamics

Systemizing an effective charge-transfer channel across a junction interface replete with ample active sites for enhancing the photocatalytic activity of semiconducting materials presents a formidable challenge. Here, we present a novel approach based on an in situ hydrothermal method for synthesizing CoFe-Layered Double Hydroxide (LDH)/CoFeCrO4 heterojunction materials that were partially derived from CoFe-LDH. These materials synergistically interact with Ti3C2 MXene nanosheets facilitating multi-interface interactions. Indeed, the highest tetracycline hydrochloride degradation rate of nearly 92% in 2 h was achieved because of the intense synergy between the CoFe-LDH/CoFeCrO4 heterojunction material optimized with 7.5 wt% of MXene nanosheets (CMC-7.5). This degradation performance was 3.1 times greater than that of the original CoFe-LDH. Further, CMC-7.5 produces the highest H2 gas of 458.79 μmol h−1g−1 from a photocatalytic water splitting reaction. The formation of a Schottky energy barrier between the partially derived CoFe-LDH/CoFeCrO4 unit and MXene promoted the fast transfer of photogenerated electrons from CoFe-LDH/CoFeCrO4 to the surface of MXene, thereby providing a plethora of active sites for photocatalytic reactions. Photoelectrochemical assessments using transient and linear sweep voltammetry along with electrochemical impedance spectroscopy confirmed efficient charge carrier transfer. Moreover, the optimized CMC-7.5 photoelectrode has a superior integral area and exhibited excellent stability over 100 cycles. Finally, the study outlines the construction of several advanced materials with multi-interface heterojunctions involving cation-exchanged LDH derivatives with high photogenerated charge carrier separation efficiency and minimal interfacial migration resistance to serve as stability benchmarks for practical applications.

A visible-light-driven dual Z-scheme CeVO4/g-C3N4/LaNiO3 hierarchical nanostructure photocatalyst for effective removal of organic pollutants

The major obstacle to restrict the practical application of photocatalysts is the low separation efficiency of photo-induced charge carriers. To overcome the above problem, a novel ternary CeVO4/g-C3N4/LaNiO3 hierarchical nanostructure photocatalyst with dual Z-scheme heterojunction is designed and fabricated by feat of semiconductor energy levels matching engineering. First, one-dimensional (1D) LaNiO3 nanobelts are fabricated by an electrospinning technique. Second, zero-dimensional (0D) g-C3N4 nanoparticles are fixed on 1D LaNiO3 nanobelts through a direct gas-solid reaction. Finally, 1D CeVO4 needle-like nanorods are fixed on g-C3N4/LaNiO3 hierarchical nanostructures through a hydrothermal method. Following exposure to visible-light irradiation for 180 min, the optimized CeVO4/g-C3N4/LaNiO3 hierarchical nanostructure photocatalyst exhibits the highest photocatalytic degradation rate (87.57%) for tetracycline hydrochloride (TCH). Additionally, under the same conditions, the photocatalyst demonstrates its broad applicability by effectively degrading various organic pollutants, including methylene blue (MB) (60.56%), bisphenol A (BPA) (68.00%), ibuprofen (IBU) (57.56%), cefuroxime sodium (CRO) (77.34%), carbamazepine (CBZ) (59.65%) and ciprofloxacin (CIP) (75.16%). The exceptional photocatalytic performance of the CeVO4/g-C3N4/LaNiO3 hierarchical nanostructure photocatalyst can be attributed to the formation of a dual Z-scheme heterojunction among the 1D CeVO4 needle-like nanorods, 0D g-C3N4 nanoparticles, and 1D LaNiO3 nanobelts. The photocatalyst has a large specific surface area and suitable semiconductor energy band positions, providing the hierarchical nanostructures with numerous surface-active sites, rapid charge transfer ability and small charge recombination rate. The design ideas and preparation method proposed in this work have guiding significance for developing other dual Z-scheme heterojunction photocatalysts.