In situ preparation of novel p-n junction photocatalyst BiOI/(BiO)2CO3 with enhanced visible light photocatalytic activity

FeSe2 and Its Composites for Pollutants Removal: Synthesis, Mechanisms, and Application Potential

In recent years, the research of FeSe2 and its composites in environmental remediation has been gradually carried out. And the FeSe2 materials show great catalytic performance in photocatalysis, electrocatalysis, and Fenton-like reactions for pollutants removal. Therefore, the studies and applications of FeSe2 materials are reviewed in this work, including the common synthesis methods, the role of Fe and Se species as well as the catalyst structure, and the potential for practical environmental applications. Hereinto, it is worth noting in particular that the lower-valent Se (Se2-), unsaturated Se (Se-), and Se vacancies (VSe) can play different roles in promoting pollutants removal. In addition, the FeSe2 material also demonstrates high stability, reusability, and adaptability over a wider pH range as well as universality to different pollutants. In view of the overall great properties and performance of FeSe2 materials compared with other typical Fe-based materials, it deserves and needs further research. And finally, this paper presents some challenges and perspectives in future development, looking forward to providing helpful guidance for the subsequent research of FeSe2 and its composites for environmental application.

Innovative Bi5O7I/MIL-101(Cr) Compounds: A Leap Forward in Photocatalytic Tetracycline Removal

In environmental chemistry, photocatalysts for eliminating organic contaminants in water have gained significant interest. Our study introduces a unique heterostructure combining MIL-101(Cr) and bismuth oxyiodide (Bi5O7I). We evaluated this nanostructure's efficiency in adsorbing and degrading tetracycline (TC) under visible light. The Bi5O7I@MIL-101(Cr) composite, with a surface area of 637 m2/g, prevents self-aggregation seen in its components, enhancing visible light absorption. Its photocatalytic efficiency surpassed Bi5O7I and MIL-101(Cr) by 33.4 and 9.2 times, respectively. Comprehensive analyses, including scanning electron microscopy (SEM) and transmission electron microscopy (TEM), confirmed the successful formation of the heterostructure with defined morphological characteristics. BET analysis demonstrated its high surface area, while X-ray diffraction (XRD) confirmed its crystallinity. Electron spin resonance (ESR) tests showed significant generation of reactive oxygen species (ROS) like h+ and·•O2- under light, crucial for TC degradation. The material maintained exceptional durability over five cycles. Density functional theory (DFT) simulations and empirical investigations revealed a type I heterojunction between Bi5O7I and MIL-101(Cr), facilitating efficient electron-hole pair separation. This study underscores the superior photocatalytic activity and stability of Bi5O7I@MIL-101(Cr), offering insights into designing innovative photocatalysts for water purification.

Synergistic Effects of Co3O4-gC3N4-Coated ZnO Nanoparticles: A Novel Approach for Enhanced Photocatalytic Degradation of Ciprofloxacin and Hydrogen Evolution via Water Splitting

This research evaluates the efficacy of catalysts based on Co3O4-gC3N4@ZnONPs in the degradation of ciprofloxacin (CFX) and the photocatalytic production of H2 through water splitting. The results show that CFX experiences prompt photodegradation, with rates reaching up to 99% within 60 min. Notably, the 5% (Co3O4-gC3N4)@ZnONPs emerged as the most potent catalyst. The recyclability studies of the catalyst revealed a minimal activity loss, approximately 6%, after 15 usage cycles. Using gas chromatography-mass spectrometry (GC-MS) techniques, the by-products of CFX photodegradation were identified, which enabled the determination of the potential degradation pathway and its resultant products. Comprehensive assessments involving photoluminescence, bandgap evaluations, and the study of scavenger reactions revealed a degradation mechanism driven primarily by superoxide radicals. Moreover, the catalysts demonstrated robust performance in H2 photocatalytic production, with some achieving outputs as high as 1407 µmol/hg in the visible spectrum (around 500 nm). Such findings underline the potential of these materials in environmental endeavors, targeting both water purification from organic pollutants and energy applications.

Evaluation of the photodegradation activity of bismuth oxoiodide/bismuth sub-carbonate nanocatalyst: Experimental design and the mechanism study

In this study, a binary BiOI/(BiO)2CO3 catalyst was prepared and used for sulfasalazine (SSZ) photodegradation in an aqueous phase. The semiconductors were identified by XRD, SEM-EDX, and UV-Vis diffuse reflectance spectroscopy (DRS) methods. Applying the Kubelka-Munk model on DRS results, the band gap energies of 2.09, 3.5, and 2.07 eV were obtained for BiOI, (BiO)2CO3, and BiOI/(BiO)2CO3 samples. pHpzc values of 6.3, 10.1, and 8.1 were estimated for BiOI, (BiO)2CO3, and BiOI/(BiO)2CO3, respectively. After observing the boosted photocatalytic activity by the coupled system, the interaction effects of the influencing variables in SSZ photodegradation were evaluated via the response surface methodology (RSM) approach. The optimal RSM-run conditions were 8.5 ppm SSZ at pH 8, which contained 0.28 g/L of the BiOI/(BiO)2CO3 catalyst and 29 min illumination time, resulting in 87% SSZ photodegradation. The effects of some scavenging agents were also studied to elucidate the relative roles of the reactive species in the SSZ photodegradation by the proposed catalyst, that is, hydroxyl radicals ∼ photoinduced electrons > superoxide radicals ∼ photoinduced holes. The proposed catalyst retained good activity after 5 successive reusing runs.

Photodegradation of Ciprofloxacin and Levofloxacin by Au@ZnONPs-MoS2-rGO Nanocomposites

This study aimed to investigate the photocatalytic performance of diverse zinc oxide catalysts containing gold nanoparticles (AuNPs), molybdenum disulfide (MoS2), and reduced graphene oxide (rGO) toward the degradation of the antibiotics levofloxacin (LFX) and ciprofloxacin (CFX) in aqueous solutions. The obtained results demonstrate that LFX is more resistant to degradation when compared with CFX and that the principal route of degradation under visible light is the formation of hydroxyl radicals. Photoluminescence (PL) measurements were employed to verify the inhibitory effect of electron–hole recombination when AuNPs, MoS2, and rGO are integrated into a semiconductor. The catalyst that achieved the highest percentage of CFX degradation was 1%Au@ZnONPs-3%MoS2-1%rGO, exhibiting a degradation efficiency of 96%, while the catalyst that exhibited the highest percentage of LFX degradation was 5%Au@ZnONPs-3%MoS2-1%rGO, displaying a degradation efficiency of 99.8%. A gas chromatography–mass spectrometry (GC-MS) analysis enabled the identification of reaction intermediates, facilitating the determination of a potential degradation pathway for both antibiotics. Additionally, recyclability assessments showed that the synthesized catalysts maintained stable photocatalytic efficiencies after 15 cycles, indicating that the heterostructures have the potential for further usage and may be tested with other organic contaminants as well.

In situ preparation of a Bi2O2CO3/BiOI with 2D/2D p-n heterojunction photocatalyst for water purification under visible light

Introduction: Semiconductors have similar crystal structures and matched energy levels could form a coupled heterojunction at an interface between them which may allow response to visible light, achieving efficient decomposition of organic compounds. Methods: The Bi₂O₂CO₃/BiOI (BOC/BOI) with 2D/2D p-n heterojunction was prepared by one-pot room-temperature strategy. The prepared materials were tested by various technologies, and the three-dimensional structure, light absorption properties, electrochemical properties and other information were obtained. Photocatalytic tests have also been carried out. Results and discussion: BOC/BOI heterojunction with oxygen vacancies showed much higher photocatalytic activity than pure BOC and BOI. For example, the preferred BOC/BOI-0.5 heterojunction of the degradation rate for Rhodamine B (RhB) is 97.6 % within 2 h, which is 15.8 and 2.2 times faster than that of BiOI and BOC. In addition, the removal rates of tetracycline, ciprofloxacin and bisphenol A by BOC/ BOI-0.5 were 92.4, 80.3 and 68.6%, respectively. The 2D/2D structures of BOC/BOI-0.5 with rich in oxygen vacancies combined p-n junction can effectively inhibit the photoinduced electron-hole pair recombination and increase the production of active free radicals. The O₂- and h+ are the main reactants, giving the composite catalyst potential for degrading a variety of pollutants.

Biomimetic Catalysts Based on Au@TiO2-MoS2-CeO2 Composites for the Production of Hydrogen by Water Splitting

The photocatalytic hydrogen evolution reaction (HER) by water splitting has been studied, using catalysts based on crystalline TiO₂ nanowires (TiO₂NWs), which were synthesized by a hydrothermal procedure. This nanomaterial was subsequently modified by incorporating different loadings (1%, 3% and 5%) of gold nanoparticles (AuNPs) on the surface, previously exfoliated MoS₂ nanosheets, and CeO₂ nanoparticles (CeO₂NPs). These nanomaterials, as well as the different synthesized catalysts, were characterized by electron microscopy (HR-SEM and HR-TEM), XPS, XRD, Raman, Reflectance and BET surface area. HER studies were performed in aqueous solution, under irradiation at different wavelengths (UV-visible), which were selected through the appropriate use of optical filters. The results obtained show that there is a synergistic effect between the different nanomaterials of the catalysts. The specific area of the catalyst, and especially the increased loading of MoS₂ and CeO₂NPs in the catalyst substantially improved the H₂ production, with values of ca. 1114 μm/hg for the catalyst that had the best efficiency. Recyclability studies showed only a decrease in activity of approx. 7% after 15 cycles of use, possibly due to partial leaching of gold nanoparticles during catalyst use cycles. The results obtained in this research are certainly relevant and open many possibilities regarding the potential use and scaling of these heterostructures in the photocatalytic production of H₂ from water.

Fabrication of Novel g-C3N4@Bi/Bi2O2CO3 Z-Scheme Heterojunction with Meliorated Light Absorption and Efficient Charge Separation for Superior Photocatalytic Performance

Herein, a novel g-C₃N₄@Bi/Bi₂O₂CO₃ Z-scheme heterojunction was synthesized via simple methods. UV/Vis diffuse reflectance spectroscopy (DRS) revealed that the visible light absorption range of heterojunction composites was broadened from 400 nm to 500 nm compared to bare Bi₂O₂CO₃. The XRD, XPS and TEM results demonstrated that metal Bi was introduced into g-C₃N₄@Bi/Bi₂O₂CO₃ composites, and Bi may act as an electronic bridge in the heterojunction. Metal Bi elevated the separation efficiency of carriers, which was demonstrated by photocurrent and photoluminescence. The performance of samples was assessed via the degradation of Rhodamine B (RhB), and the results exhibited that g-C₃N₄@Bi/Bi₂O₂CO₃ possessed notably boosted photocatalytic activity compared with g-C₃N₄, Bi₂O₂CO₃ and other binary composites. The heterojunction photocatalysts possessed good photostability and recyclability in triplicate cycling tests. Radical trapping studies identified that h⁺ and •O₂^- were two primary active species during the degradation reaction. Based on the energy band position and trapping radical experiments, the possible reaction mechanism of the indirect Z-scheme heterojunction was also proposed. This work could provide an effective reference to design and establish a heterojunction for improving the photocatalytic activity of Bi₂O₂CO₃.

Photocatalytic Degradation of Fluoroquinolone Antibiotics in Solution by Au@ZnO-rGO-gC3N4 Composites

The photocatalytic degradation of two quinolone-type antibiotics (ciprofloxacin and levofloxacin) in aqueous solution was studied, using catalysts based on ZnO nanoparticles, which were synthesized by a thermal procedure. The efficiency of ZnO was subsequently optimized by incorporating different co-catalysts of gC3N4, reduced graphene oxide, and nanoparticles of gold. The catalysts were fully characterized by electron microscopy (TEM and SEM), XPS, XRD, Raman, and BET surface area. The most efficient catalyst was 10%Au@ZnONPs-3%rGO-3%gC3N4, obtaining degradations of both pollutants above 96%. This catalyst has the largest specific area, and its activity was related to a synergistic effect, involving factors such as the surface of the material and the ability to absorb radiation in the visible region, mainly produced by the incorporation of rGO and gC3N4 in the semiconductor. The use of different scavengers during the catalytic process, was used to establish the possible photodegradation mechanism of both antibiotics.

Hydroxyl-assisted iodine ions intercalating Bi2O2CO3 nanosheets to constructure the interlayered bridge for enhanced photocatalytic activity of phenol

Promoting the charge migration and separation efficiency of Bi2O2CO3 is an appealing strategy to improve its photocatalytic performance. Herein, iodine-intercalated Bi2O2CO3 (I-Bi2O2CO3) nanosheets were prepared with the assistance of solvents...

Optimized strategies for (BiO)2CO3 and its application in the environment

Photocatalysis is a new type of technology, which has been developed rapidly for solving environmental problems such as wastewater or air pollutants in recent years. Also, the effective performance and non-secondary pollution of photocatalytic technology attract much attention from researchers. As a "sillén" phase oxide, the (BiO)₂CO₃ (BOC) is a great potential photocatalyst attributing to composed of alternate Bi₂O₂²⁺ and CO₃^2- layers, which is a benefit for transportation of electrons. Besides, BOC has attracted much attention from researchers because of its excellent characters of non-toxic, environmentally friendly, and low-cost. However, BOC has a defect on wide band gap, which is limited for the usage of visible light, so a great number of published papers focus on the modifications of BOC to improve its photocatalytic efficiency. This article mainly summarizes the modifications of BOC and its application in the environment, guiding for designing BOC-based materials with high photocatalytic activity driven by light. Moreover, the research trend and prospect of BOC photocatalyst were briefly summarized, which could lay the foundation for forming a green and efficient BOC-based photocatalytic reaction system. Importantly, this review might provide a theoretical basis and guidance for further research in this field.

Advances in Theoretical Calculation of Halide Perovskites for Photocatalysis

Photocatalysis, which includes water splitting for hydrogen fuel generation, degradation of organic pollutants, and CO2 reduction using renewable solar energy, is one of the most promising solutions for environmental protection and energy conversion. Halide perovskite has recently emerged as a new promising material for photocatalytic applications. The exploration of new efficient halide perovskite-based photocatalysts and understanding of photocatalytic reaction mechanisms can be revealed using theoretical calculations. The progress and applications of first-principles atomistic modeling and simulation of halide perovskite photocatalysts, including metal halide perovskites, halide perovskite heterojunctions, and other promising perovskite derivatives, are presented in this review. Critical insights into the challenges and future research directions of photocatalysis using halide perovskites are also discussed.

Interface engineering of heterojunction photocatalysts based on 1D nanomaterials

1D nanomaterial-based heterojunctions with unique structures and outstanding physicochemical properties are divided into several types including type II heterojunction, p–n type heterojunction, Schottky junction, Z-type heterojunction, and S-scheme heterojunction.

La-doping induced localized excess electrons on (BiO)2CO3 for efficient photocatalytic NO removal and toxic intermediates suppression

Photocatalysis technology has been extensively adopted to abate typical air pollutants. Nevertheless, it is a challenge to develop photocatalysts aiming to simultaneously improve photocatalytic selectivity and efficiency. In this study, to improve the photocatalytic selectivity and the performance of (BiO)₂CO₃ in the oxidation of NO to target products (NO₂^- /NO₃^-), we developed a novel method to construct La-doped (BiO)₂CO₃ (La-BOC) for forming localized excess electrons (Ex) on (BiO)₂CO₃ surface. The results indicate that the Ex could effectively accelerate the activation of reactants and promote charge separation and transfer. Under visible light, the gas molecules could capture the Ex and get activated to produce reactive oxygen species (ROS) with high oxidation ability, which enables complete oxidation of NO to target products instead of producing other toxic by-products. Due to the functionality of the Ex, the photocatalytic selectivity and efficiency of La-BOC have been synchronously improved. Combining experimental and theoretical methods, this work unravels the pathway of charge carriers transportation/transformation and elucidates the photocatalytic NO oxidation mechanism. The present work could provide a novel method to improve photocatalytic selectivity and activity for safe air pollutant abatement.

Construction and visible-light-photocatalysis of a novel ternary heterostructure BiOI/(001)TiO2/Ti3C2

Constructing effective heterojunctions between semiconductors and appropriate cocatalysts and exposing highly active crystal facets have been considered an effective approach to obtain efficient photocatalysts. Herein, a novel BiOI/(001)TiO₂/Ti₃C₂ (BTT) hybrid was for the first time synthesized by in situ growing (001)TiO₂ nanosheets on a 2D MXene nanomaterial (Ti₃C₂) and subsequent deposition of flower-like nanoflake BiOI on the obtained (001)TiO₂/Ti₃C₂ hybrid. The BTT hybrid exhibited excellent photocatalytic performance for degradation of Rhodamine B under visible light irradiation, with the highest degradation rate being 6.26, 1.72, and 1.35 times of that of a pure BiOI, BiOI/TiO₂ hybrid, and BiOI/Ti₃C₂ hybrid, respectively. The staggeringly enhanced photoactivity of BTT was attributed to the separation of photogenerated carriers by a multiple charge transfer channels because of the formed p-n and Schottky double junctions. This study demonstrates that (001)TiO₂/Ti₃C₂ obtained by simple hydrothermal oxidation of Ti₃C₂ can be a good cocatalyst for fabricating excellent visible-light-driven photocatalyst.

Magnetically Recoverable TiO2/SiO2/γ-Fe2O3/rGO Composite with Significantly Enhanced UV-Visible Light Photocatalytic Activity

In this paper, we report the preparation of a new composite (TiO₂/SiO₂/γ-Fe₂O₃/rGO) with a high photocatalytic efficiency. The properties of the composite were examined by different analyses, including X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), photoluminescence (PL), UV-Visible light diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy (FTIR), Raman, vibrating-sample magnetometer (VSM), and nitrogen gas physisorption (BET) studies. The photocatalytic efficiency of the proposed composite was evaluated by the degradation of methylene blue under UV and visible light, and the results were compared with titanium dioxide (TiO₂), where degradation increased from 30% to 84% and 4% to 66% under UV and visible light, respectively. The significant increase in photocatalytic activity may be explained by the higher adsorption of dye on the surface of the composite and the higher separation and transfer of charge carriers, which in turn promote active sites and photocatalytic efficiency.

Evaluation and prospects of nanomaterial-enabled innovative processes and devices for water disinfection: A state-of-the-art review

This study provided an overview of established and emerging nanomaterial (NM)-enabled processes and devices for water disinfection for both centralized and decentralized systems. In addition to a discussion of major disinfection mechanisms, data on disinfection performance (shortest contact time for complete disinfection) and energy efficiency (electrical energy per order; E_EO) were collected enabling assessments firstly for disinfection processes and then for disinfection devices. The NM-enabled electro-based disinfection process gained the highest disinfection efficiency with the lowest energy consumption compared with physical-based, peroxy-based, and photo-based disinfection processes owing to the unique disinfection mechanism and the direct mean of translating energy input to microbes. Among the established disinfection devices (e.g., the stirred, the plug-flow, and the flow-through reactor), the flow-through reactor with mesh/membrane or 3-dimensional porous electrodes showed the highest disinfection performance and energy efficiency attributed to its highest mass transfer efficiency. Additionally, we also summarized recent knowledge about current and potential NMs separation and recovery methods as well as electrode strengthening and optimization strategies. Magnetic separation and robust immobilization (anchoring and coating) are feasible strategies to prompt the practical application of NM-enabled disinfection devices. Magnetic separation effectively solved the problem for the separation of evenly distributed particle-sized NMs from microbial solution and robust immobilization increased the stability of NM-modified electrodes and prevented these electrodes from degradation by hydraulic detachment and/or electrochemical dissolution. Furthermore, the study of computational fluid dynamics (CFD) was capable of simulating NM-enabled devices, which showed great potential for system optimization and reactor expansion. In this overview, we stressed the need to concern not only the treatment performance and energy efficiency of NM-enabled disinfection processes and devices but also the overall feasibility of system construction and operation for practical application.

(002) Oriented Bi2O2CO3 Nanosheets with Enhanced Photocatalytic Performance for Toluene Removal in Air

Layer-structured Bi2O2CO3 is a novel photocatalyst for eliminating environmental pollutants. In this work, Bi2O2CO3 nanosheets were synthesized by hydrothermal methods, followed by annealing in nitrogen. (002) oriented Bi2O2CO3 nanosheets were obtained and characterized by XRD, SEM, XPS, BET and UV-Vis diffuse reflectance spectra. Photocatalytic properties were investigated by toluene removal in air, with the assistant of Bi2O2CO3 nanosheets under artificial irradiation. Our results show that Bi2O2CO3 annealed in nitrogen exhibited high full-light-driven photocatalytic activity for toluene photocatalytic decomposition, which may be ascribed to facet orientation evolution during the annealing process and enhanced efficient charge separation. The sample annealed at 150 °C for 8 h (BOC-150-8 h) showed high stability and the highest toluene removal rate, which was up to 99%. The final degradation products were detected by gas chromatography–mass spectrometer (GC-MS) and CO2 was verified to be the primary product. Photocatalytic mineralization of toluene in air over Bi2O2CO3 was proposed. This work may provide a foundation for application of annealed Bi2O2CO3 in indoor air purification.

Enhanced visible light-active CeO2/CuO/Ag2CrO4 ternary heterostructures based on CeO2/CuO nanofiber heterojunctions for the simultaneous degradation of a binary mixture of dyes

CeO₂/CuO/Ag₂CrO₄ composite is fabricated using an electrospinning and precipitation. Also, composite can photodegrade RB and MB under visible light irradiation. CeO₂/CuO/Ag₂CrO₄ can enhanced photocatalytic activity due to formed heterojunction.

Constructing a new Z-scheme multi-heterojunction photocataslyts Ag-AgI/BiOI-Bi2O3 with enhanced photocatalytic activity

The series Ag-AgI/BiOI-Bi₂O₃ visible-light-driven photocataslyts were successfully synthesized by solvothermal method. The as-synthesized samples were systematically characterized by XRD, SEM, TEM, EDS, BET, XPS, FR-IR, UV-vis DRS, photoelectrochemical measurements and EPR. The formation mechanism of the new composite photocataslyts was investigated and the simulate formation process had been illustrated. The photocatalytic properties of the samples were evaluated by degradation of methyl orange under visible-light irradiation. The results shown that the 30% Ag-AgI/BiOI-Bi₂O₃ photocataslyts possessed the best photocatalytic activity and the kinetics reaction models were followed pseudo-first-order kinetics. The enhanced photocatalytic performance could be attributed to the effective separation and transfer of electron-hole pairs resulting by the deposing of Ag-AgI nanoparticles and Bi₂O₃. The photocatalytic mechanism was deduced by trapping experiments and EPR, and the results demonstrated that h⁺, OH, O₂^- radicals played different roles in the degradation. Furthermore, a new Z-scheme multi-heterojunction mechanism was proposed basing on the results of trapping experiments and EPR.

Recent Developments in the Photocatalytic Treatment of Cyanide Wastewater: An Approach to Remediation and Recovery of Metals

For gold extraction, the most used extraction technique is the Merrill-Crow process, which uses lixiviants as sodium or potassium cyanide for gold leaching at alkaline conditions. The cyanide ion has an affinity not only for gold and silver, but for other metals in the ores, such as Al, Fe, Cu, Ni, Zn, and other toxic metals like Hg, As, Cr, Co, Pb, Sn, and Mn. After the extraction stage, the resulting wastewater is concentrated at alkaline conditions with concentrations up to 1000 ppm of metals. Photocatalysis is an advanced oxidation process (AOP) able to generate a photoreaction in the solid surface of a semiconductor activated by light. Although it is well known that photocatalytic processes can remove metals in solution, there are no compilations about the researches on photocatalytic removal of metals in wastewater with cyanide. Hence, this review comprises the existing applications of photocatalytic processes to remove metal and in some cases recover cyanide from recalcitrant wastewater from gold extraction. The use of this process, in general, requires the addition of several scavengers in order to force the mechanism to a pathway where the electrons can be transferred to the metal-cyanide matrices, or elsewhere the entire metallic cyanocomplex can be degraded by an oxidative pathway.

Heterostructural design of I-deficient BiOI for photocatalytic decoloration and catalytic CO2 conversion

I⁻ vacancies in BiOI play a major role in governing the photocatalysis and catalysis.

Anoxic photocatalytic treatment of synthetic mining wastewater using TiO2and scavengers for complexed cyanide recovery

A new pathway for selective photocatalytic reduction using a combination of scavengers for gold mining wastewater treatment.

Synthesis of nanocrystalline strontium titanate by a sol–gel assisted solid phase method and its formation mechanism and photocatalytic activity

Strontium titanate (SrTiO₃) with a perovskite structure is widely applied to hydrogen production by photolysis water splitting.

Intensive photocatalytic activity enhancement of Bi5O7I via coupling with band structure and content adjustable BiOBrxI1-x

Band structure and component content are the key factors for determining the activity of semiconductor heterojunction. In this study, a novel Bi₅O₇I/BiOBr_xI_1-x heterostructure was synthesized by a simple hydrobromic (HBr) acid etching method through transforming partial of Bi₅O₇I to I^- ion doped BiOBr (BiOBr_xI_1-x) at room temperature without adding extra dopant. Both the band structure and component content of Bi₅O₇I/BiOBr_xI_1-x alter with the additive HBr acid. The Bi₅O₇I/BiOBr_xI_1-x (S3.0) sample exhibits the best photocatalytic activity, 6 times higher than that of pure Bi₅O₇I, for the degradation of methyl orange under visible-light (λ > 420 nm). The activity enhancement of Bi₅O₇I/BiOBr_xI_1-x is primarily ascribed to the improved separation efficiency of photocharges, originated from the adjustable band structure and component content. The significant findings of this paper provide a facile way to construct highly efficient semiconductor heterojunction via playing the synergetic effect of adjustable band structure and component content for purifying organic pollutants in wastewater.