Ternary Heterojunction Photocatalyst Research Articles

Constructing dual-channel carrier transport in AgBr/BiOBr/Ag3PO4 heterojunctions for enhanced photocatalytic NO removal

Efficient and stable photocatalysts are indispensable for effectively reducing nitrogen oxide (NOx) emissions. This study presents a facile method for synthesizing AgBr/BiOBr/Ag3PO4 composites and investigates their application in photocatalytic NO removal. The optimized composite exhibited notable performance, achieving 54.95 % removal of NO (approximately 568 ppb reduced to 256 ppb) under visible light irradiation, which is about 1.6 and 2.0 times higher than single Ag3PO4 (34.95 %) and BiOBr (28.01 %), respectively. Comprehensive physicochemical characterization highlighted enhancements in light absorption and the generation of reactive radicals within the AgBr/BiOBr/Ag3PO4 composite. The favorable electronic structure, characterized by well-aligned redox band positions, facilitated efficient dual carrier transport routes, thereby promoting the separation of photo-generated charge carriers. Additionally, in-situ DRIFTS analysis revealed that the composite facilitated the conversion of intermediates into nitrates during the NO purification process. This work contributes valuable insights into designing and preparing of ternary heterojunction photocatalysts with dual carrier transport channels, advancing strategies for achieving superior photocatalytic performance.

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.

Innovative synthesis of ternary heterojunction CuInS2/BiOI/Bi2MoO6 for 2,4-DCP degradation and its dechlorination performance

This study focuses on a novel ternary heterojunction catalyst for the removal of 2,4-dichlorophenol (2,4-DCP), an organic pollutant that is difficult to degrade. An efficient CuInS2/BiOI/Bi2MoO6 ternary heterojunction photocatalyst was formed by constructing a CuInS2/BiOI composite layer on a Bi2MoO6 substrate using an in-situ growth technique. The microstructure and photoelectric conversion properties of the catalysts were comprehensively resolved by systematic material characterization, including scanning electron microscopy (SEM) observation, X-ray photoelectron spectroscopy (XPS) analysis and photoelectrochemical testing. The experimental results showed that the optimized catalyst at a loading of 2.0 g/L exhibited excellent photocatalytic degradation efficiency against 20 mg/L concentration of 2,4-DCP at neutral pH, reaching 80.3 % degradation rate in 120 min. This high performance was mainly attributed to the enhanced charge-carrier separation mechanism at the heterojunction interface, which effectively enhanced the utilization and transfer rate of photogenerated electron-hole pairs and enhanced the photocatalytic activity of the catalyst. In addition, the study also deeply explored the conversion pathway of elemental chlorine in the photocatalytic system, elucidated the mechanism of 2,4-DCP degradation and dechlorination, and provided a theoretical basis for further improving the environmental adaptability and dechlorination efficiency of the catalyst. Overall, the CuInS2/BiOI/Bi2MoO6 ternary heterojunction photocatalysts proposed in this study demonstrate a broad application prospect in the purification of 2,4-DCP and other organic pollutants, and open up a new way to solve the problems of industrial wastewater treatment, which is of great environmental significance and scientific value.

Synergetic photocatalytic degradation of the tetracycline antibiotic over S-scheme based BiOBr/CuInS2/WO3 ternary heterojunction photocatalyst

The present research investigated the photodegradation capability of a ternary BiOBr/CuInS2/WO3 heterojunction against the tetracycline (TC) antibiotic. BiOBr/CuInS2/WO3 heterojunction is formed using a straightforward physical mixing method, whereas pure photocatalysts (CuInS2, WO3) were synthesized hydrothermally and BiOBr by a coprecipitation process. The Field Emission Scanning Electron Spectroscopy examination validated the nanorod and nanosheet shape of the fabricated BiOBr-CuInS2-WO3. The photodegradation capabilities of the BiOBr-CuInS2-WO3 heterojunction were superior to those of other pure photocatalysts, and it followed the S-scheme charge transfer route as indicated by the band alignments. After 120 min of light irradiation, the BiOBr/CuInS2/WO3 S-scheme ternary heterojunction obtained a photodegradation rate of 98.9 %, much greater than other pure photocatalysts. According to electron spin resonance investigations and scavenging experiments, the radicals hydroxyl radicals (•OH), hole (h+), superoxide (•O2−) play a significant role in the photodegradation of TC. The ternary heterojunction's improved light absorption, lower recombination rate, and higher photocarrier separation rate were due to the fabrication of S-scheme heterojunction. The ternary BiOBr/CuInS2/WO3 photocatalyst's photodegradation efficacy was consequently enhanced. Investigations for photocatalyst reusability demonstrated its exceptional stability, with a 93.8 % degradation rate after five catalytic cycles.

Facile synthesis of NH2-MIL-53(Al)@BiOBr@CQDs ternary heterostructure photocatalyst for degradation of ciprofloxacin in water

The construction of ternary heterojunction photocatalysts can achieve multi-gradient transfer of charges and accurate control the position of photogenerated electrons which has received increasing attention. In this paper, NH2-MIL-53(Al)@BiOBr@CQDs-10 % (ABCQDs-10 %) was prepared via a facile hydrothermal and chemical synthesis processes. Three-dimensional serration of NH2-MIL-53(Al) as a platform for irregular BiOBr nanosheets, CQDs promote interfacial contact and act as electron transport channels between BiOBr and NH2-MIL-53(Al) and constitute Z-type heterojunctions with high redox properties. ABCQDs-10 % shows the best photocatalytic removal efficiency (94.24 %) of CIP, the reaction rate constants (0.045 min−1) were 1.2 and 64 times higher than BiOBr and NH2-MIL-53(Al), respectively. The excellent degradation performance is attributed to the construction of Z-type heterojunction of NH2-MIL-53(Al)@BiOBr@CQDs which improve electron-hole separation and transfer efficiency. The main active species was •O2-. The photocatalytic activity of ABCQDs-10 % had not obvious loss after cycle experiments and the crystal structure had no significant changes, means high stable photocatalytic activity.

Rational design and construction of direct Z-scheme ternary heterojunction photocatalyst AgBr/CoWO4/Ag for efficient environmental remediation

The indiscriminate discharge of micropollutants (e.g., dyes, antibiotics, industrial additives, etc.) represents a significant risk to human health, and the removal of these substances from water bodies has become a prominent area of research within the field of environmental remediation. A simple hydrothermal-precipitation-photoreduction method was employed to synthesize novel Z-scheme heterojunction photocatalysts of AgBr/CoWO4/Ag. The catalysts demonstrated remarkable degradation capabilities with regard to a range of micropollutants present in wastewater. Of the catalysts tested, 5AgBr/CoWO4/Ag exhibited the highest degradation rates, reaching 98.58% for Rhodamine B, 86.82% for tetracycline hydrochloride, and 95.60% for 2-mercaptobenzothiazole within 60 min. In particular, the reaction kinetic rate of 5AgBr/CoWO4/Ag towards Rhodamine B degradation (k2 = 0.26278 L mg−1·min−1) is 9 times that of AgBr (k2 = 0.02953 L mg−1·min−1) and 113 times that of CoWO4 (k2 = 0.00233 L mg−1·min−1), which serves to highlight the exceptional photocatalytic activity of the material. The experimental data and subsequent analysis indicated that the enhanced photocatalytic performance can be attributed to two factors: firstly, the electron mediation by Ag nanoparticles leading to improved charge separation efficiency, and secondly, the formation of Z-scheme heterojunctions between AgBr and CoWO4. The cyclic tests provided confirmation of the excellent stability and recyclability of the AgBr/CoWO4/Ag photocatalysts. It is anticipated that this study will facilitate the development of novel methods for the degradation of refractory micropollutants and provide insights into environmental remediation, thereby contributing to the sustainable development of society.

Construction of metal-free dual S-scheme heterojunction photocatalysts by rational band alignment for efficient hydrogen evolution

Designing ternary heterojunction photocatalysts is regarded as a compelling approach to attain exceptional photocatalytic activity. However, they always suffer from poor interfacial contact and unclear charge transfer pathways. Herein, a metal-free dual S-scheme heterojunction photocatalyst comprised of black phosphorus (BP), carbon nitride (CN), violet phosphorus (VP) was designed by electrostatic self-assembly. The non-metallic feature of the BPCNVP heterostructure facilitates to form strong interfacial contact by coordinating active P sites in VP and BP with N atoms in CN. Notably, a definite dual S-scheme heterojunction configuration is achieved by rational band alignment of VP and BP, respectively, which significantly boosts the driving force for charge separation. The BPCNVP heterostructure exhibited a hydrogen evolution rate of 1669μmol h-1g−1 with excellent stability, surpassing most reported metal-free photocatalysts. This work demonstrates that the design of dual S-scheme heterojunction by metal-free materials provides valuable insights into the intricate reaction mechanism of ternary heterojunction photocatalysts.

Construction of novel Fe6W18O70/In2WO6/Ag-doped g-C3N4 ternary heterojunction photocatalyst for photodegradation of various environmental contaminants

Construction of novel Fe6W18O70/In2WO6/Ag-doped g-C3N4 ternary heterojunction photocatalyst for photodegradation of various environmental contaminants

Unveiling the potential of a g-C3N4/BiOBr/Bi2O2CO3 ternary heterojunction photocatalyst for rechargeable zinc-air battery: Visible-light-driven photo-assisted charging for bifunctional ORR and OER at the air cathode

Advancements in solar-driven energy storage technology have been achieved for rechargeable zinc-air batteries (RZABs), facilitating accelerated kinetic responses in both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In this study, we successfully synthesized a novel g-C3N4/BiOBr/Bi2O2CO3 ternary heterojunction through a facile hydrothermal process, demonstrating its efficacy as a bifunctional photocatalyst. Upon exposure to LED irradiation, this heterojunction triggers an effective separation of the photogenerated electron-hole pairs, resulting in enhanced oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performance by 46.19 % and 65.69 % respectively, compared to non-LED conditions. Interestingly, the reduction in the potential gap under LED irradiation (0.06 V), correlating with a significant 2.71 % increase in round-trip efficiency (RTE), is observed. In addition, the optimized band alignment derived from g-C3N4/BiOBr/Bi2O2CO3 ternary heterojunction for photo-assisted charging rechargeable zinc-air batteries is proposed. Insightfully, photo-enhanced charging in RZABs mechanism during the charge/discharge process through in-situ X-ray absorption spectroscopy (XAS) is monitored, confirming the large interaction between O2 adsorption and Bi 6d orbitals of g-C3N4/BiOBr/Bi2O2CO3 in the presence of LED. In conclusion, our innovative g-C3N4/BiOBr/Bi2O2CO3 ternary heterojunction underscores the significant role that visible-light-driven photocatalysts can play in enhancing the efficiency of rechargeable zinc-air batteries.

Constructing a CeFeO3/LaFeO3/ZnIn2S4 double Z-scheme heterojunction for photocatalytic atrazine degradation under visible light irradiation

The limited light absorption range and rapid recombination of interfacial charges were deemed to be the main restriction of the photocatalysts for atrazine (ATZ) degradation, and the construction of Z-scheme heterojunction was an effective strategy. Herein, a CeFeO3/LaFeO3/ZnIn2S4 (CFO/LFO/ZIS) double Z-scheme ternary heterojunction photocatalyst was fabricated by the in-situ precipitation and hydrothermal method. The photocatalytic ATZ degradation efficiency of optimized heterojunction reached 52% within 175 min under visible light irradiation, which was 3.1, 3.7 and 1.7 times higher than that of CFO, LFO and ZIS, respectively. The enhanced photocatalytic activity was due to the excellent light capture capacity and improved photogenerated charge separation in CFO/LFO/ZIS double Z-scheme heterojunction photocatalyst. Meanwhile, some environmental factors on the influence of photocatalytic ATZ degradation performance were systematically investigated. Quenching experiments confirmed that ·OH, h+ and 1O2 were the main active species during the photocatalytic ATZ degradation process. The possible photogenerated charge separation route was proposed via the analysis of the IEF effects between CFO, LFO and ZIS. Finaly, the possible ATZ degradation pathway was deduced by LC-MS measurement and toxicity assessment of the intermediates were also evaluated by the Toxicity Estimation Software Tool (TEST). This work not only provided a potential magnetic recyclable ferrate based double Z-scheme heterojunction photocatalyst for enhancing photogenerated charge separation and light absorption, but also evaluated the intermediate toxicity and related environmental factors on the activity of photocatalyst, which was facilitating the practical application for the degradation of ATZ.

A facile synthesis of metal vanadate incorporated with metal oxide/rare earth metal oxide composite for photocatalytic application

In this work (Ag2O/BiVO4) binary and (Ag2O/BiVO4/Eu2O3) ternary heterojunction photo-catalysts have been synthesized through a hydrothermal technique for the purpose of photocatalytic degradation of hazardous dyes. The facile synthesized composites of (Ag2O/BiVO4) and (Ag2O/BiVO4/Eu2O3)have been prepared using a hydrothermal process. The synthesized composites used to degrade the Methylene blue and Congo-red dyes under sunlight. The X-ray diffraction confirms the crystalline structure of synthesized composites. The calculated crystalline sizes for (Ag2O/BiVO4) and (Ag2O/BiVO4/Eu2O3) are 9.9 nm and 2.84 nm respectively. The morphology of samples has been analyzed by SEM while the absorption spectrum and bonding of molecules were observed using FTIR in the range of 600–4000 cm−1. The elemental percentage of synthesized material is determined by using EDX spectroscopy and UV spectroscopy used to study optical properties. Using Tauc plot calculated band gap of (Ag2O/BiVO4)is 1.84 eV and (Ag2O/BiVO4/Eu2O3) is 1.65 eV. The degradation efficiency of composites(Ag2O/BiVO4) (Ag2O/BiVO4/Eu2O3) towards a dye MB is 38% and 41% respectively, while these composites were found to degrade the dye CR 82% and 99%respectively in the exposure of sunlight. Both synthesized composites showed excellent %age degradation toward acidic dye (CR). The outcomes of synthesized composites indicates that suitable optical absorption, better segregation of charge carries and reduction of electron-hole recombination these factor effectively contribute to enhance photocatalytic activity towards acidic dye CR.

G-C3N4 as ballistic electron transport “Tunnel” in CsPbBr3-based ternary photocatalyst for gas phase CO2 reduction

Perovskite CsPbBr3 quantum dot shows great potential in artificial photosynthesis, attributed to its outstanding optoelectronic properties. Nevertheless, its photocatalytic activity is hindered by insufficient catalytic active sites and severe charge recombination. In this work, a CsPbBr3@Ag-C3N4 ternary heterojunction photocatalyst is designed and synthesized for high-efficiency CO2 reduction. The CsPbBr3 quantum dots and Ag nanoparticles are chemically anchored on the surface of g-C3N4 sheets, forming an electron transfer tunnel from CsPbBr3 quantum dots to Ag nanoparticles via g-C3N4 sheets. The resulting CsPbBr3@Ag-C3N4 ternary photocatalyst, with spatial separation of photogenerated carriers, achieves a remarkable conversion rate of 19.49 μmol·g−1·h−1 with almost 100 % CO selectivity, a 3.13-fold enhancement in photocatalytic activity as compared to CsPbBr3 quantum dots. Density functional theory calculations reveal the rapid CO2 adsorption/activation and the decreased free energy (0.66 eV) of *COOH formation at the interface of Ag nanoparticles and g-C3N4 in contrast to the g-C3N4, leading to the excellent photocatalytic activity, while the thermodynamically favored CO desorption contributes to the high CO selectivity. This work presents an innovative strategy of constructing perovskite-based photocatalyst by modulating catalyst structure and offers profound insights for efficient CO2 conversion.

Synthesis and characterization of Fe2SiO4/Fe2O3/g-C3N4 ternary heterojunction photocatalyst with enhanced photocatalytic activity under visible light

Ultrasonic-assisted co-precipitation is used for the first time to prepare Z-scheme Fe2SiO4/Fe2O3/g-C3N4 ternary heterojunction photocatalysts. Their morphology, crystal structure, specific surface area, optical properties, composition, and photocatalytic behavior have been thoroughly examined. When compared to single-component and binary Fe2SiO4/Fe2O3 heterojunction photocatalysts, ternary Fe2SiO4/Fe2O3/g-C3N4 heterojunction photocatalysts exhibit the most profitable performance for degradation of erythrosine under simulated light. It is likely that this is due to the high rate of separation migration of photoexcited charge carriers, the formation of Z-scheme heterojunction, and the specific surface area. Based on the results of active species trapping experiments, a possible Z-scheme mechanism could explain the significantly reduced photocatalytic rate of ternary heterojunction photocatalysts. It has been demonstrated that superoxide radicals play a significant role in the photodegradation process. A kinetic analysis revealed that the higher efficiency (97.9%) was associated with a higher rate constant (k = 0.0345 min‒1). A Fe2SiO4/Fe2O3/g-C3N4 nanocomposite is an excellent choice for large-scale applications because of its exceptional stability and recyclability.

Rational design of a g-C3N4/CdS/MIL-125 (Ti)-derived TiO2 ternary heterojunction as a highly efficient photocatalyst for wastewater treatment under visible-light irradiation

A highly efficient g-C3N4/CdS/TiO2 ternary heterojunction photocatalyst with a hollow structure has been fabricated using a step-by-step self-assembly strategy.

Construction of a visible light responsive dual Z-scheme NH2-MIL-101(Fe)/CdS/g-C3N4 ternary heterojunction photocatalyst for efficient CO2 photoreduction to methanol

The photocatalytic CO2 reduction reaction using various semiconductors is exceedingly difficult due to the recombination of photo-exited electron-hole (e−, h+), inefficient irradiated light utilization, and lower adsorption capacity of CO2. An efficient design of the photocatalyst system is required to address this issue. The metal–organic frameworks (MOFs), particularly NH2-MIL-101(Fe) (NML-101(Fe)), have demonstrated exceptional efficiency in CO2 adsorption, and reduction because of its large surface area, efficient charge separation capacity, and ligand-to-metal charge transfer effect (LMCT). The synergistic effect of semiconductors CdS, g-C3N4 (GCN), and metal–organic framework on efficient photocatalytic CO2 conversion to CH3OH was investigated here. The successful synthesis and design of a dual Z-scheme NML-101(Fe)/CdS/GCN (NMCG(X)) ternary hetero-nanostructured system (THS) was demonstrated, in which CdS nanoparticles and NML-101(Fe) are deposited on the surface of GCN to form a dual Z-scheme mechanism with excellent photocatalytic performance. After 8 h of visible light irradiation, NMCG8 nanocomposites containing 37.5 % GCN, 25 % CdS, and 37.5 % NML-101(Fe) exhibit 1.53 times higher methanol production (53.89 µmolg−1) than pure NML-101(Fe) (35.11 µmolg−1). The efficient reduction of CO2 was largely attributed to the systematic transportation of photo-exited e− and h+ mediated by the dual Z-scheme mechanism, as demonstrated by PL spectra, electrochemical impedance spectra (EIS) studies, and Transient photocurrent response testing.

Hydrothermal carbonization carbon induced synthesis of flower-like C/Bi/BiOI heterojunction with heightened photocatalytic Cr(VI) reduction

Modification with metallic Bi and formation heterojunction with carbon material are considered as the compelling strategies to address the shortcoming of bismuth oxyhalide in photocatalytic Cr(VI) reduction. However, the simultaneous and in-situ synthesis of metallic Bi and hydrothermal carbonization carbon (HC) on BiOI to fabricate a ternary heterojunction photocatalyst remains a challenge yet, and the synergistic mechanism between the localized surface plasmon resonance (LSPR) effect and HC is still indistinct. Herein, a ternary heterojunction photocatalyst comprising metallic Bi, HC, and flower-like BiOI was designed and synthesized through the in-situ induction of HC. During the solvothermal synthesis, a portion of Bi3+ was reduced to metallic Bi nanoparticles, and simultaneously gauzy HC was formed. In the ternary heterojunction, the metallic Bi nanoparticles displayed strong LSPR effect, and the coated HC was conducive to transferring photogenerated electrons and enriching Cr(VI). Due to the synergistic effect of metallic Bi and HC, multiple channels for photogenerated carrier transfer were constructed. Deriving from the excellent light-harvesting, accelerated transfer/separation, and restrained recombination of photogenerated carriers, the ternary heterojunction of flower-like C/Bi/BiOI showed superior photocatalytic Cr(VI) reduction. The reaction rate constant of photocatalytic Cr(VI) reduction was about 26 times higher than that of BiOI.

Recent updates on g-C3N4/ZnO-based binary and ternary heterojunction photocatalysts toward environmental remediation and energy conversion

Background: The utilization of photocatalytic materials has garnered significant consideration due to their distinctive properties and diverse applications in environmental remediation and energy conversion. In photocatalysis, several wide and narrow band gap photocatalysts have been discovered. Amongst several photocatalysts, g-C3N4 photocatalyst is becoming the interest of the research community due to its unique properties. But as a single photocatalyst, it is inherited with certain confines for instance higher photocarrier recombination rate, lower quantum yield, low specific surface area, etc. However, the heterojunction formation of g-C3N4 with other wide band gap photocatalysts (ZnO) has improved its photocatalytic properties by overcoming its limitations.
 Methods: The synergistic interaction amid g-C3N4 and ZnO photocatalysts enhanced optoelectrical properties superior mechanical strength and improved photocatalytic activity. The nanocomposite exhibits excellent stability, high surface area, efficient separation, and migration of photocarriers, which are advantageous for applications in photocatalytic energy conversion and environmental remediation. The g-C3N4-ZnO nanocomposite represents a material comprising g-C3N4 and ZnO photocatalysts which exhibit a broad absorption range, efficient electron-hole separation, and strong redox potential. The combination of these two distinct materials imparts enhanced properties to the resulting nanocomposite, making it suitable for various applications. Henceforth, current review, we have discussed the photocatalytic properties of g-C3N4 and ZnO photocatalysts and modification strategies to improve their photocatalytic properties.
 Significant Findings: This article offers an inclusive overview of the g-C3N4-ZnO-based nanocomposite, highlighting its photocatalytic properties and potential applications in several pollutant degradation and energy conversion including hydrogen production and CO2 reduction.

Dual Z‐scheme ternary heterojunction photocatalyst with enhanced visible‐light photocatalytic degradation of organic pollutants

AbstractPhotocatalysis technology driven by solar energy is considered to be promising for solving energy crisis and environmental problems. Graphitic carbon nitride has been widely researched in the photocatalysis field due to its suitable band positions, non‐toxicity, easy synthesis, high stability, and low cost. However, the slow separation and rapid recombination of photogenerated carriers, the poor visible light response and the low specific surface area seriously limit the photocatalytic activity of g‐C3N4. Here, firstly, g‐C3N4 nanosheets with a large specific surface area of 152.2 m2 g−1 which provide more surface‐active sites for photocatalysis were prepared by secondary calcination method. Next, MoS2 and metal–organic framework (MIL‐101(Cr)) were tightly bonded on g‐C3N4 nanosheets to form ternary g‐C3N4/MoS2/MIL‐101(Cr) heterojunction photocatalyst. In which, a ternary dual Z‐scheme heterojunction photocatalyst composed of g‐C3N4, MoS2, and MIL‐101(Cr) was constructed to facilitate the separation and the migration of photogenerated charges. At the same time, MoS2 enhanced the visible light response of the ternary photocatalyst. The optimal ternary photocatalyst displayed the highest activity for methyl orange degradation (degradation efficiency of 98% in 60 min) under visible light irradiation. Finally, a photocatalytic mechanism of a dual Z‐scheme electron transfer channel and h+‐·O2− double oxidation sites were proposed and discussed.

Construction of a novel double S-scheme heterojunction CeO2/g-C3N4/Bi2O4 for significantly boosted degradation of tetracycline: Insight into the dual charge transfer mode

Constructing dual S-scheme heterojunction, as one kind of new strategy for the reinforcement of photocatalytic property, shows significant advantages in facilitating the migration of photoinduced charges and achieving high redox potentials. Herein, a novel double S-scheme heterojunction CeO2/g-C3N4/Bi2O4 was designed and synthesized successfully. The photodegradation of tetracycline (TC) over CeO2/g-C3N4/Bi2O4 was carried out under the irradiation of visible light. The double S-scheme interfacial charge transmission mode of CeO2/g-C3N4/Bi2O4 was investigated according to Fermi level, band structure, and the in-depth analysis of in situ irradiated X-ray photoelectron spectroscopy (ISI-XPS) and electron spin resonance (ESR) spectra. The CeO2/g-C3N4/Bi2O4 exhibits excellent catalytic activity with a high TC removal efficiency of 94 % and a remarkable mineralization efficiency of 51 %. The rate constant (0.05811 min−1) of TC degradation for CeO2/g-C3N4/Bi2O4 is 12.9, 7.8, 4.3, 2.2, and 3.1 times those for g-C3N4, CeO2, Bi2O4, g-C3N4/Bi2O4 and CeO2/g-C3N4, separately. The prominently boosted activity may be due to two factors. Firstly, the successful creation of the double S-scheme electron migration channel greatly boosts the transmission of photogenerated carriers, represses the recombination of electrons with holes, and ensures the strongest redox potential of CeO2/g-C3N4/Bi2O4. Secondly, the introduction of Bi2O4 with excellent visible-light absorption broadens the optical absorption region of CeO2/g-C3N4/Bi2O4. Additionally, the influence of the typical environmental factors (pH, inorganic anions, cations, and natural humus) on the photodegradation of TC was explored. The three probable pathways for TC degradation were inferred via analyzing intermediates. The current work offers a novel outlook for enhancing the activity of ternary heterojunction photocatalysts applied in environmental restoration.

Construction of dual Z-scheme g-C3N4/BiVO4 (0 4 0)/In2S3 photocatalyst for efficient photocatalytic degradation and sterilization under solar light irradiation

A novel ternary heterojunction photocatalyst, g-C3N4/BiVO4/In2S3, is synthesized via a hydrothermal method, exhibiting superior photocatalytic activity in tetracycline (TC) degradation and Escherichia coli (E. coli) inactivation. The first-order kinetic constant of TC degradation by MCN/BVO/InS-1 under simulated solar light is 3.6, 1.8, 2.9 and 1.4 times that of MCN, BVO, InS, and MCN/BVO, respectively. More than 90 % of E. coli can be inactivated within 60 min by MCN/BVO/InS composite. After three consecutive cycles of experiments, the prepared photocatalyst showed continuous excellent stability. In this system, superoxide radicals (∙O2-) dominate TC degradation, while photogenerated h+ is key in E. coli inactivation. TC degradation pathways are analyzed by LC-MS/MS and theoretical calculations. A dual Z-scheme electron transfer mechanism is proposed. Furthermore, the ecotoxicity of TC and its degradation intermediates is examined through the application of the Toxicity Estimation Software Tool (T.E.S.T.) and Quantitative Structure-Activity Relationship (QSAR) model. The findings of the MCN/BVO/InS photocatalyst could provide insights for designing and optimizing novel photocatalytic systems with broader applications in the remediation of waterborne contaminants.