Double Heterojunction Research Articles

Performance and mechanism of Bi2WO6/AgI/ZnFe2O4 double Z-scheme heterojunction photocatalyst for tetracycline hydrochloride degradation under visible light

Performance and mechanism of Bi2WO6/AgI/ZnFe2O4 double Z-scheme heterojunction photocatalyst for tetracycline hydrochloride degradation under visible light

Visible light-activated signal amplification PEC aptasensor for ultrasensitive zearalenone detection based on double Z-type BiOI/g-C3N4@Au/Bi2S3 heterojunctions

Zearalenone (ZEN), also known as F-2 toxin, can enter the body through the food chain and accumulate, leading to DNA break and an abnormal number of chromosomes. Therefore, it is crucial to develop a facile and sensitive method for detecting ZEN. Herein, a visible light-activated signal amplification photoelectrochemical (PEC) aptasensor for ultrasensitive detection of ZEN has been successfully constructed, exploiting the synergistic effect of the Z-type BiOI/g-C3N4/Au heterojunctions, Bi2S3 as a signal enhancer, and the remarkable affinity and specificity of aptamers. The PEC properties and electron transfer mechanism of the double Z-type heterojunctions were thoroughly investigated. When the aptamers captured the ZEN molecules, Bi2S3 and cDNA departed from the electrode, resulting in a reduction in the photocurrent signal. Therefore, the concentration of ZEN can be quantitatively analyzed by measuring the change in the photocurrent response. The constructed PEC aptasensor exhibited exceptional sensitivity and selectivity for ZEN in the concentration range of 0.1 fg⋅mL−1 ––1.0 ng⋅mL−1, with a detection limit of 0.087 fg⋅mL−1 (S/N = 3). Finally, the PEC aptasensor was successfully applied to detect ZEN in actual coix seed samples, providing some guidance for the development of PEC aptasensors for practical medicine monitoring.

Constructing artificial photosynthetic system based on graphdiyne double heterojunction to enhance REDOX capacity and hydrogen evolution efficiency

Although traditional type II heterojunction designs for artificial photosynthesis show promise for photocatalytic hydrogen production, their redox capacity is somewhat limited due to the spatial separation of hydrogen evolution and oxidation reactions at less favorable sites. To overcome this limitation, ohmic junctions based on type II heterojunctions have been designed to enhance hydrogen evolution by transferring electrons to the metal component. In this study, a copper powder graphdiyne (Cu-GDY) composite catalyst with ohmic angle contact was synthesized by coupling copper foil with hexa-hexylbenzene. Incorporating Cu-GDY into CoGdO3 results in an interleaved band structure forming a type II heterojunction at the contact interface. This configuration overcomes the issue of the unfavorable conduction band position of CoGdO3, thereby promoting charge transfer. The internal electric field created by the Fermi level difference between Cu-GDY and CoGdO3, increase in REDOX capacity is the main reason for the increase of carrier separation rate. In addition, the plasmonic properties of copper expand the active reaction sites and promote the hydrogen evolution reaction. The composite catalyst exhibits b a hydrogen production rate that is 10.5 times higher than that of the individual catalysts. This work demonstrates that the formation of two distinct contact interfaces between Cu-GDY and CoGdO3 significantly improves the electron transfer and hydrogen evolution performance.

Fabrication of double S-scheme Sr2MgSi2O7:Eu2+,Dy3+/ZnIn2S4/UiO-66-NH2 heterojunctions with photon storage effect for enhanced round-the-clock photocatalysis

Persistent light-emitting materials (PLMs), which have the potential to store and release light energy after light irradiation, are receiving increasing attention for their role in prolonging the lifetime of photogenerated electrons for the development of photocatalysts with round-the-clock applications. In this paper, a double S-scheme Sr2MgSi2O7:Eu2+,Dy3+/ZnIn2S4/UiO-66-NH2 (SZU) heterojunction with round-the-clock catalytic activity was prepared by hydrothermal self-assembly method. The photocatalytic performance of the SZU heterojunction for RhB(MB) degradation was significantly improved compared with the pristine ZnIn2S4 and UiO-66-NH2. The SZU heterojunction has excellent catalytic degradation performance for RhB (MB), and the removal rate of RhB (MB) reaches 72.2 % (81.7 %) after visible light irradiation for 40 (60) minutes. After the end of light, the total removal rate of RhB (MB) reached 86.7 % (96.8 %) when the catalysis continued for several hours under dark conditions, which was 14 % and 15 % higher than that under visible light irradiation, respectively. Based on the characteristics of SMS photoluminescence, combined with a large number of photocatalytic experiments, The sustained photocatalytic activity was enhanced under both daytime and darkness conditions, not only because of the production of SZU complexes, which prolonged the visible light response of ZnIn2S4, but also because of the construction of double S-scheme heterojunctions, which facilitates the light storage capacity, charge transfer, and the separation of photo-induced charge carriers and effectively promoted the photocatalytic activity of the photocatalysts. This work contributes to a deeper understanding of the design of round-the-clock photocatalysts, and provides a useful exploration for the practical application of photocatalytic technology.

Photocatalytic fuel cell based on dual Z-scheme heterojunction photoanode InVO4/g-C3N4/Bi2WO6/Ti for efficient Rhodamine B degradation and power generation

Finding suitable semiconductor materials to construct efficient photoanode is the key to improve PFC performance. In this paper, InVO4/g-C3N4/Bi2WO6/Ti composite photoanode was prepared and assembled with Cu cathode to construct PFC for rhodamine B (RhB) degradation and power generation. The InVO4/g-C3N4/Bi2WO6/Ti photoanode was characterized by XRD, FT-IR, XPS, SEM, TEM, EDS and DRS. The electrochemical properties of the PFC including polarization curves, power density, transient photocurrent, LSV and CV curves were analyzed to explore its power generation and electron transfer mechanism. The results showed that the ternary composite photoanode had stronger light absorption, smaller Eg (1.96 eV) and Rct (0.71 Ω), and higher photocurrent current density (0.16 mA cm−2) than binary and single composite photoanodes, indicating that it had higher utilization rate of excitation light energy and carrier mobility. The RhB degradation rate, Pmax, Jsc and Voc of PFC were 93.1 % (90 min), 18.02 µW cm−2, 0.223 mA cm−2 and 0.44 V, respectively. Further mechanistic studies show that the PFC has good photoexcited carrier separation and strong redox capacity due to double Z-scheme heterojunction between Bi2WO6 and InVO4 and between Bi2WO6 and g-C3N4, so as to generate more O2− and h+ to degrade RhB through N-deethylation, dealkylation and ring opening reactions. This study provides a practical approach for the development of high-efficiency double Z-scheme composite photoanode.

Photocatalytic degradation of norfloxacin antibiotic by a novel Cu-ZnO/BiOI/Bi2WO6 double Z-type heterojunction: Performance, mechanism insight and toxicity assessment

A novel double Z-type Cu-ZnO/BiOI/Bi2WO6 photocatalyst was synthesized using one-pot hydrothermal method. The effects of Bi2WO6 and Cu-ZnO contents, antibiotic concentration, catalyst dosage, solution pH value, coexisting ions, antibiotic types, mixed antibiotic types, water source and light source on the catalytic performance of the Cu-ZnO/BiOI/Bi2WO6 were investigated. Remarkably, under visible light irradiation, the removal rate of 20 mg/L norfloxacin reached 94.32 % within 120 min using the optimized Cu-ZnO/BiOI/Bi2WO6 photocatalyst, and its pseudo-first-order reaction rate constants were 5.63 and 1.80 times higher than those of BiOI and BiOI/Bi2WO6, respectively. The toxicity prediction and experimental findings indicated that the toxicity of the degraded norfloxacin (NOR) solution was notably diminished. The Cu-ZnO/BiOI/Bi2WO6 catalyst exhibited excellent salt tolerance, high reusability stability, universality and spectral response. Outstanding photocatalytic performance of Cu-ZnO/BiOI/Bi2WO6 photocatalyst is primarily due to the co-recombination of Cu-ZnO and Bi2WO6 on BiOI, which increases the surface area and active sites of the catalyst. More importantly, the double Z-type heterojunction, created through the intimate union of the semiconductor boundary within the composite catalyst, enhances the interface charge transport efficacy and the efficiency of separating photogenerated carriers. Finally, in conjunction with a diverse range of experimental methodologies, the degradation pathway of NOR through the Cu-ZnO/BiOI/Bi2WO6 composite catalyst and the electron transfer mechanism within the double Z-type heterojunction have been comprehensively elucidated. This study provides a pioneering reference for optimizing BiOI-based heterojunction catalysts and addressing antibiotic-contaminated wastewater treatment.

Ternary photocatalyst Bi5O7I/Bi2O2CO3/Ag2CO3 with double Z-scheme heterojunction for the degradation of levofloxacin under visible light: Practical application and DFT calculation

A novel double Z-scheme heterojunction Bi5O7I/Bi2O2CO3/Ag2CO3 was constructed by a simple hydrothermal calcination and one-step in-situ growth technique, demonstrating efficient levofloxacin degradation (86.9 % in 60 min). The degradation rates of the system are 1.5, 4.1, 1.3 and 1.4 times faster than those of pure Bi5O7I, Bi2O2CO3, Ag2CO3 and binary Bi5O7I/Bi2O2CO3, respectively. The method enhances the photocatalyst performance through improving the separation efficiency of electron-hole pairs (e-/h+) and the production of various free radicals in the double Z-scheme system. The generation of hydroxyl radicals (•OH), superoxide radicals (•O2–) and holes (h+) species were directly confirmed by Electron Spin Resonance test, and their contributions on the degradation of Levofloxacin follow the order of h+ > •OH > •O2–. The band structure, density of states, work function and potential sites of contaminant vulnerability in the material were determined by Density Functional Theory (DFT), which provides additional evidence for the formation of double Z-scheme heterojunction. Besides, the degradation experiment was conducted with four real surface water bodies, including lake water, river water, tap water and effluent of sewage treatment plant. The results show that the degradation rate for Levofloxacin reaches 60∼80 %. Moreover, Levofloxacin and its intermediate products were identified and their toxicity was predicted with Quantitative Structure-Activity Relationship (QSAR) modelling, which can be useful in the future for the actual design of a double Z-scheme heterojunction photocatalyst to efficiently remove pollutants under visible light irradiation.

Enhancing CO2 photoreduction efficiency with MXene-modified ZnO@Co3O4 double heterojunction

The photocatalytic reduction of CO2 into energy carriers holds significant industrial appeal, but achieving this process kinetically remains challenging due to the lack of well-designed catalysts. This study presents a novel 2D/3D nanostructured photocatalyst, developed by attaching a few-layer Ti3C2 MXene to polyethylenimine (PEI)-modified ZnO@CO3O4 nanocages, which are derived from a bimetallic zinc-cobalt ZIF. The resulting Mx-PEI-ZnO@Co3O4 catalyst achieved impressive yields of CO and CH4 at 594.37 and 42.67μmol g−1h−1, respectively, without the need for sacrificial agents and photosensitizers, and maintained remarkable stability across multiple cycles. These yields represent the highest performance for ZnO-based catalysts to date, with quantum efficiency at 380 nm reached up to 25.06 %. The unique S-scheme and Mott-Schottky junctions, along with enhanced CO2 adsorption and hydrogen-bond interactions facilitated by the conductive PEI within the Ti3C2/ZnO/Co3O4 double heterojunctions, effectively inhibit electron-hole recombination and significantly enhance CO2 photoreduction performance. This study underscores the combined benefits of double heterojunction engineering, PEI-functionalized CO2 uptake, and MXene co-catalyst integration within a single system, proposing a new approach for designing highly efficient photocatalysts for solar-driven CO2 reduction in energy-efficient fuel production.

Enhanced Photoelectrochemical Water Splitting Using NiMoO4/BiVO4/Sn-Doped WO3 Double Heterojunction Photoanodes.

Efficient photoelectrochemical (PEC) water splitting systems in photoelectrodes are primarily challenged by electron-hole pair recombination. Constructing a heterostructure is an effective strategy to overcome this issue and to enhance PEC efficiency. In this study, we integrated NiMoO4, known for its proper electrocatalytic conductivity, into a BiVO4/Sn-doped WO3 heterojunction using solution-based hydrothermal and spin-coating methods, forming an innovative double heterojunction concept. The resulting NiMoO4/BiVO4/Sn:WO3 triple-layer heterojunction photoanode exhibits a photocurrent density of 2.06 mA cm-2 in a potassium borate buffer (KBi) electrolyte at 1.23 V vs RHE, outperforming the bilayer BiVO4/Sn:WO3 heterojunction (1.45 mA cm-2) and Sn:WO3 photoanodes (0.55 mA cm-2) by approximately 1.4 and 3.7 times, respectively. Remarkably, the NiMoO4/BiVO4/Sn:WO3 double heterojunction photoanode exhibits notable stability, showing only an approximate 30% reduction in initial photocurrent density after 10 h of measurement in the KBi electrolyte without a hole scavenger. This stability is attributed to the excellent corrosion resistance of the thin NiMoO4 layer, effectively protecting the bilayer BiVO4/Sn:WO3 heterojunction photoanode from photocorrosion. Our findings show how this novel double heterojunction, established through simple and cost-effective solution-based methods, offers a promising approach to enhancing PEC water splitting applications.

MoS2/CuS/g-C3N4 double S-scheme with charge storage ability for efficient photocatalytic H2 production

The photocatalytic H2 production technology exhibits promising potential in addressing the challenges of environmental pollution and energy crisis. In this work, CuS particles decorated MoS2 seaweed spheres (MoS2/CuS) were synthesized through a hydrothermal method, then they are loaded on the surface of g-C3N4 nanosheets using a solvent evaporation strategy to form MoS2/CuS/g-C3N4 double S-scheme heterojunction. The investigation reveals the H2 production rate of 25 wt% MoS2/CuS/g-C3N4 can reach up to 1438 μmol·g-1·h-1, which is 14.8-fold of g-C3N4 (97 μmol·g-1·h-1). Further studies indicate that the introduction of MoS2/CuS can broaden the light absorption range, increase electrochemical specific surface area, reduce the activation energy for H2 production and increase hydrophilicity of the composite. Especially, CuS can suppress carrier recombination effectively through its electron storage and release ability. Based on the experimental and theoretical analysis of band structures, the charge transfer in MoS2/CuS/g-C3N4 shares optimized double S-scheme charge transfer pathways with a dual reduction site, leading to an enhanced H2 evolution kinetics. This work offers valuable insights for the advancement of novel double S-scheme heterojunctions, showcasing their potential in energy storage and photothermal enhancement effects.

Enhanced photocatalytic degradation of organic dyes by dual heterojunction of ZnO/NiWO4/V2C MXene

Multiphase composite catalysts can be designed for efficient photocatalytic treatment of organic pollutants in wastewater. Herein, the multiphase ZnO/NiWO4/V2C composite catalysts with dual heterojunction and hierarchically assembled nanoflower structures were constructed via a facile two-step hydrothermal and electrostatic self-assembly method. Utilizing NiWO4 and V2C as co-catalysts, these catalysts effectively degraded cationic dyes, methylene blue (MB) and rhodamine B (RhB) under visible light irradiation. The ZnO/NiWO4/V2C catalyst exhibited higher photocatalytic activity than ZnO in the degradation of MB and RhB, with rate constants of 0.0194 min−1 (a 7.43-fold enhancement) and 0.0176 min−1 (a 3.13-fold enhancement). The higher activity can be attributed to the construction of the double heterojunction using NiWO4 and V2C, which can facilitate efficient electron transport, improve charge separation efficiency, and provide more active sites. After four cycles, the ZnO/NiWO4/V2C catalyst still maintained good stability. Consequently, this work can offer a promising approach for environmental pollution treatment.

A novel persulfate activation strategy by double Z-scheme Bi2O3/CuBi2O4/BiOBr heterojunction: Non-radical dominated pathway for levofloxacin degradation

Persulfate advanced oxidation technology (PS-AOPs) is known as a novel wastewater treatment method. Considering the poor self-stability of Bi2O3/CuBi2O4, we synthesized Bi2O3/CuBi2O4/BiOBr ternary composite material and established the non-radical pathway-dominated peroxymonosulfate (PMS) activation system. The study indicated that BiOBr promoted electron migration on the material surface. Bi2O3/CuBi2O4/BiOBr/Vis/PMS system exhibited excellent catalytic performance (86.83 % within 100 min), significantly higher than Bi2O3/CuBi2O4 (63.19 %) and BiOBr (60.35 %). Furthermore, it has strong catalytic activity and adaptability to various environmental conditions. By quenching experiments and EPR analysis, O2−∙ and 1O2 were the main active species. Finally, possible degradation pathways and intermediates were predicted through liquid mass spectrometer (LC-MS), and toxicity analysis was conducted on levofloxacin (Lev) and intermediates. The degradation mechanism may be attributed to the construction of double Z-scheme heterojunction, photogenerated electron transfer and ROS generation through the redox cycle of Cu2+/Cu+ and Bi5+/Bi3+.

Synthesis of MoS2@MoO3/(Cu+/g-C3N4) ternary composites with double S-scheme heterojunction for peroxymonosulfate activation exposing to visible light

The construction of semiconductor heterojunction is an effective way for charge separation in photocatalytic degradation of pollutants. In this study, a novel MoS2@MoO3/(Cu+/g-C3N4) ternary composites (MMCCN) was prepared via a simple calcination method. The as-prepared composites exhibited exceptional performance in activating peroxymonosulfate (PMS) for the degradation of rhodamine B (RhB). The activity testing results indicated that 99.41 % of RhB (10 mg·L−1, 10 mL) was effectively removed by the synergistic effect of composites photocatalyst (0.1 g·L−1) and PMS (0.1 g·L−1) under visible light irradiation for 40 min. Its reaction rate constant exceeded that of Cu+/g-C3N4, MoO3 and MoS2 by a factor of 3.56, 17.30 and 11.73 times, respectively. The crystal structure, band gap and density of states (DOS) of the semiconductors were calculated according to the density functional theory (DFT). Free radical trapping tests and electron spin resonance spectroscopy validated that 1O2, O2− and h+ are primary reactive species participating in the decomposition of RhB. The ternary composites demonstrated good stability and maintained excellent degradation efficiency even across four reaction cycles. Furthermore, the activation mechanism and the intermediates produced during the decomposition course of RhB by MMCCN/PMS/vis system were analyzed and elucidated. A double S-scheme heterojunctions was responsible for efficient separation of photo-induced electron-hole pairs. This work presents a novel method in the construction of double S-scheme heterojunctions for PMS activation which is expected to find wide applications in wastewater treatment and environmental remediation.

Temperature Dependence of Reaction Kinetics in a Hybrid GaAs Solar-Fuel Cell Device.

The recently proposed single-electrode fuel cell (SEFC) is based on the chemovoltaic effect in a semiconductor p-n junction and as a hybrid device also allows operation as a photovoltaic cell. This study investigates the temperature dependence of the chemovoltaic effect in GaAs/GaInP p-n double heterojunction SEFC devices in the presence of both liquid and vapor methanol as a fuel. The experimental results reveal that increasing the temperature from room temperature to around 45 °C significantly enhances the fuel cell's performance by accelerating the electrochemical oxidation and reduction reactions injecting electrons and holes into the semiconductor bands. However, further increase in the fuel temperature, nearing the boiling point of methanol, leads to adverse effects on the cell's performance when submerged in the liquid fuel but still shows moderate improvement when operating with the vapor-phase fuel. These results provide insight into the kinetics of the chemovoltaic effect in a hybrid solar-fuel cell device.

High-Visible Light Response AgNbO3/Bi2MoO6/PANI Double Z-Scheme Heterojunction Photocatalytic Degradation of Antibiotics.

In this study, a novel AgNbO3/Bi2MoO6/PANI double Z-scheme heterojunction photocatalyst was created via a solvothermal method, and the method investigates its photocatalytic degradation performance toward norfloxacin (NOR) and other antibiotics. When the content of AgNbO3 is 5 wt % and the content of PANI is 1 wt %, the rate of degradation of AgNbO3/Bi2MoO6/PANI on NOR under visible light is 95.56%, the rate of removal of total organic carbon is ∼57.45%, and its pseudo-first-order reaction rate constant is 0.01878 min-1, which surpasses those of AgNbO3, Bi2MoO6, and AgNbO3/Bi2MoO6 by factors of 14.22, 2.46, and 1.35, respectively. At the same time, the AgNbO3/Bi2MoO6/PANI photocatalyst still showed good stability after three cycles. The results demonstrated that the augmented photocatalytic performance of AgNbO3/Bi2MoO6/PANI can be attributed to the formation of a double Z-scheme heterojunction and the incorporation of PANI with excellent conductivity, resulting in the higher efficiency of migration of charge carriers while retaining strong redox ability. This work affords a high-efficiency and environmentally friendly reference for the development of a Bi2MoO6-based heterojunction photocatalyst and its application in the purification of antibiotics in water.

Construction of g-C3N4@Bi-MOF@BiOCl double Z-type heterojunctions for photodegradation of antibiotics under visible light irradiation: Mechanism, pathway, and toxicity assessment

In this study, flower-like microspheres dispersed double Z-type heterojunction g-C3N4@Bi-MOF@BiOCl photocatalysts were prepared using Bi-MOF as the structural template. The photocatalyst showed good degradation ability for both tetracycline antibiotics under simulated sunlight irradiation, as well as stable recyclability and total organic carbon mineralization (TOC). This excellent photocatalytic activity was mainly attributed to the formation of double Z-type heterojunctions that accelerated charge separation and transfer and drove stronger redox capacity. In addition, the effects of conditions such as catalyst dosage, initial concentration of tetracycline hydrochloride (TC) and initial pH (3–11) value of the solution on the photocatalytic reaction were investigated. The results of free radical trapping experiments and ESR analyses indicated that O2−, h+ and OH were the active free radicals that could not be neglected for the degradation of tetracycline hydrochloride (TC), and a possible degradation mechanism was further proposed. Finally, the possible pathways for degradation of the intermediates were rationally deduced by gas chromatography (GC–MS) and evaluated by ecotoxicity analysis based on the utilization rate (T.E.S.T.) of the intermediates produced. This study provides an effective idea for the rational design and synthesis of highly efficient dual Z-type photocatalysts for antibiotic contamination in water-polluted environments.

Rational design double S-scheme heterosystem based Photo-Electrocatalytic membrane device for continuous phytotoxin remediation

Today, the escalating contamination of water sources with phytotoxins poses a significant danger to both ecosystems and human health. Consequently, the implementation of advanced and sustainable remediation technologies becomes imperative for the effective removal of toxins. This study introduces a pioneering method for continuous phytotoxin remediation by integrating a photoelectrocatalytic membrane reactor, which utilizes a ZnCdFeSe heterojunction photocatalyst with a double S-scheme, is derived from the ZnCd prussian blue analog. This design capitalizes on the unique electronic structure and synergistic effects of the catalyst enabling efficient photo-electrocatalysis in the device. The proposed system attains an impressive phytotoxin rejection efficiency of 98.39%, accompanied by enhanced membrane permeation and anti-fouling performance. The obtained results are noteworthy for an emerging process that combines the simultaneous degradation and separation of toxic species, enabling prolonged and uninterrupted remediation processes. Experimental and density function theory (DFT) results demonstrate that, under optimal conditions, the well-stabilized double S-scheme ZnCdFeSe heterojunction achieves a mineralization rate of 85.67%. Even after six cycles of the photocatalytic membrane, the removal rate of ricin remains high at 78.96%, indicating the membrane’s commendable reusability and stability. This research not only contributes to the advancement of innovative environmental remediation strategies but also provides valuable insights for designing and optimizing photoelectrocatalytic systems for the persistent removal of toxins in water treatment applications.

In situ proof construction of GDY/NiWO4/CdS double S-scheme heterojunction: Improving charge transfer and promoting photocatalytic activity

In the field of photocatalysis, the inherent properties of catalysts are a hard condition that affects catalytic performance, and constructing heterojunctions is a common method to improve catalyst defects and enhance catalyst performance. This article makes effective use of the outstanding stability and unique electronic structure of graphdiyne, along with its excellent semiconductor properties comparable to silicon. It uses these properties to attach rod-shaped CdS and microspherical NiWO4 onto sheet-like graphdiyne, creating an S-scheme heterojunction. With the construction of S-scheme heterojunctions and the special contact methods between the three, the physical potential barrier and the distance of electron transfer are reduced. Furthermore, the combined impact of NiWO4 and graphdiyne works to inhibit the photo corrosion of CdS, enhance its electron transfer capabilities, decrease electron-hole recombination efficiency, and boost hydrogen evolution sites. This maximizes the redox potential during catalysis, leading to exceptional stability and efficiency of the composite catalyst. This study opens up a new avenue for leveraging the superior properties of graphdiyne and advancing sustainable practices.

Co2-Fe8-BTC/g-C3N4/Bi2O3/Ti photoanode for visible light responsive photocatalytic fuel cell degradation of rhodamine B and electricity generation

The Co2-Fe8-BTC/g-C3N4/Bi2O3/Ti photoanode with the double Z-type heterojunction was produced by hydrothermal technique and to assemble visible light responsive photocatalytic fuel cell (PFC) with Cu cathode. The synthesized photoanode was characterized by SEM, FT-IR, XPS, XRD and UV–vis DRS analysis. The maximum photocurrent density, maximum power density, and rhodamine B degradation rate of the PFC were 0.53 mA·cm-2, 33.56 μW·cm-2, and 96.89 % (60 min), respectively, which were much higher than these of PFCs with g-C3N4/Bi2O3/Ti photoanode (0.19 mA·cm-2, 11.64 μW·cm-2, 55.37 %, respectively) and Bi2O3/Ti photoanode (0.15 mA·cm-2, 6.63 μW·cm-2, 41.67 %, respectively). The electricity generation performance and rhodamine B degradation of this PFC system is greatly enhanced by the double Z-type heterojunctions of the photoanode among Co2-Fe8-BTC, g-C3N4 and Bi2O3, which accelerates the isolation of photogenerated carriers, and also retains good redox capability, thus obtaining high photocatalytic activity. This work can serve as reference for the design and heterojunction construction of high-efficiency photoanode of PFC with visible light response.

Integration of Bi nanoparticles with brown TiO2 co-modified by Bi2Fe4O9 and BiFeO3: Double S-scheme photocatalysts towards degradation of pollutants

Recently, plasmonic photocatalysts fabricated using non-noble element of Bi have presented promising performances to tackle environmental and energy issues. Herein, we integrated Bi nanoparticles with brown TiO2 (denoted as TOX) co-modified by Bi2Fe4O9/BiFeO3 components to fabricate double S-scheme plasmonic photocatalysts through a one-pot hydrothermal route. The results showed that the optimum TOX/Bi2Fe4O9/BiFeO3/Bi photocatalyst decomposed tetracycline about 36.1, 7.05, and 5.13 times superior than TOX, Bi2Fe4O9/BiFeO3, and TOX/Bi2Fe4O9/BiFeO3 samples, respectively. More importantly, the resulting plasmonic photocatalyst exhibited superior photodegradation activities against the removal of other antibiotics such as azithromycin and amoxicillin, and dyes such as methylene blue, malachite green, and rhodamine B upon visible light. The extraordinary performance of rationally designed plasmonic photocatalyst was devoted to more harnessing of visible light and boosting charge segregation among the components facilitated by double S-scheme heterojunctions. The scavenging studies exhibited the formation of •OH, •O2−, and h+ reactive species over TOX/Bi2Fe4O9/BiFeO3/Bi nanocomposite under visible light. Considering the high stability, facile fabrication procedure, excellent biocompatibility, and impressive performance of TOX/Bi2Fe4O9/BiFeO3/Bi photocatalyst in destroying a wide range of contaminants in water, it is inferred that other impressive plasmonic photocatalysts-based on Bi can be designed and developed for effectively addressing the environmental issues upon visible light.