Construction Of Heterojunction Research Articles

Sub-2.5 nm monodisperse Mo2C nanoparticles on N-doped carbon: The facet engineering for boosting electrochemical hydrogen evolution

Molybdenum carbide materials have demonstrated remarkable potential in catalyzing the hydrogen evolution reaction (HER). However, further modulation of their performance through simultaneously engineering the size and surface crystal facets remains challenging. Herein, we report the successful fabrication of N-doped carbon-supported monodisperse Mo2C nanoparticles with a size of ∼2.06 nm, exhibiting co-exposed (101)/(102) facets-heterojunction, derived from annealing glycine and ammonium molybdate tetrahydrate. The optimized Mo2C/NC-Amt catalyst exhibits a low overpotentials of 128 mV to achieve the current density of 10 mA cm−2 and a small Tafel slope of 72 mV dec−1 under alkaline solution. By changing the molybdate precursor, the phase and crystal facet composition of molybdenum carbide can be effectively tuned, which provides a good platform for studying their structure-activity in HER. The theoretical calculations reveal the synergistic effect of (101)/(102) facets-heterojunction accelerates electron transfer and regulates the d band center of Mo2C, reducing the reaction barriers of intermediates in the HER process, thus significantly boosting reaction activity. This work proposes a novel insight into the rational fabrication of efficient HER catalysts through facet engineering toward heterojunction construction under the 2.5 nm region.

CuS@MoS2 p[sbnd]n heterojunction photocatalyst integrating photothermal and piezoelectric enhancement effects for tetracycline degradation

Photocatalysis is an environmentally friendly and low-cost technology for the degradation of pollutants. In addition to the construction of heterojunction which may decrease the recombination of charge carriers and extend the photo-response range, the utilization of piezoelectricity and photothermal conversion also provides the promising routes to improve the photocatalytic performance. Herein, a CuS@MoS2 heterostructure was developed to simultaneously meet the needs of these enhancement mechanisms. The formation of pn heterojunction was confirmed and the associated energy band diagram was constructed with band gaps of CuS and MoS2 as 1.56 and 1.80 eV, respectively. For the degradation of tetracycline, it was demonstrated that the inherent piezoelectric property of MoS2 surface enhanced the piezocatalytic activity by inducing an electric field to aid charge separation. The heat generated by illumination raised the photocatalytic reaction rate by supplying extra energy to carriers. The CuS@MoS2 heterostructure exhibited significantly better catalytic performance than the individual CuS or MoS2 due to the formation of pn heterojunction. Furthermore, the combination of piezoelectricity and photothermal conversion also led to a significant synergistic effect, achieving a degradation efficiency of over 95% within 30 min. As compared to the conditions under ultrasonic vibration, visible light irradiation and visiblenearinfrared light irradiation alone, the combination of visiblenearinfrared irradiation and ultrasonic vibration could lead to 96, 205 and 81% enhancement. This work provides valuable insights into the design of novel heterojunction photocatalysts integrating the piezoelectric and photothermal enhancement effects.

Construction of Cs2AgBiCl6/COF Heterojunction for Boosted Photocatalytic Thioester Oxidation.

Lead-free halide perovskites as a new kind of potential candidate for photocatalytic organic synthesis have attracted much attention recently. The rational heterojunction construction is regarded as an efficient strategy to delicately regulate their catalytic performances. Herein, a semi-conductive covalent organic framework (COF) nanosheet, C4N, is employed as the functional component to construct Cs2AgBiCl6/C4N (CABC/C4N) heterojunction. It is found that the C4N nanosheets with rich surface functional groups can serve as heterogeneous nucleation sites to manipulate the growth of CABC nanocrystals and afford close contact between each other, therefore facilitate the transfer and spatial separation of photogenerated charge carriers, as verified by in situ X-ray photoelectronic spectroscopy and Kelvin probe force microscopy. Moreover, the oxygen affinity of C4N endows the heterojunctions with outstanding aerobic reactivity, thus improving the photocatalytic performance largely. The optimal CABC/C4N heterojunction delivers a thioanisole conversion efficiency of 100% after 6h, which is 2.2 and 7.7-fold of that of CABC and C4N. This work provides a new ideal for the design and application of lead-free perovskite heterojunction photocatalysts for organic reactions.

BiOClxM1-x (M=I, Br) solid solution-coupled CdS photocatalysts for enhanced visible light-driven organic pollutants degradation with simultaneous hydrogen production

The construction of Z-scheme heterojunction stands out as one of the most effective modification methods for enhancing the performance of photocatalysts. Therefore, BiOClxM1-x (M=I, Br) solid solution-coupled CdS (BiOClxM1-x/CdS) Z-scheme photocatalysts were successfully synthesized by a hydrothermal-precipitation method. BiOCl0.8I0.2/CdS exhibited notable photocatalytic performance with a hydrogen yield of 261 μmol/g, which was 2.23, 1.56 and 1.44 times higher than that of CdS, BiOCl/CdS and BiOCl0.5Br0.5/CdS, respectively. This improvement can be attributed to two key factors: (1) the formation of BiOClxM1-x (M=I, Br) solid solution enhances visible light absorption; (2) The formation of BiOCl0.8I0.2/CdS (M=I, Br) Z-scheme heterojunctions inhibit the recombination of photogenerated carriers to prolong the lifetime of photogenerated carriers, thus increasing the utilization of the photogenerated carriers. Moreover, BiOCl0.8I0.2/CdS also showed good photocatalytic activity in ROW-DFHP (residual organic wastewater from dark fermentation for hydrogen production), with a hydrogen production rate of 42.83 μmol/g and a mineralization rate of organic pollutants of 31.73%. Cycling experiments, XRD and SEM of the samples before and after the photocatalytic reaction showed that BiOCl0.8I0.2/CdS has good stability. Furthermore, the mechanism of BiOCl0.8I0.2/CdS for the photocatalytic degradation of organic pollutants and simultaneous hydrogen production was proposed, offering a novel strategy for organic wastewater purification and hydrogen energy recovery.

In Situ Etching-Hydrolysis Strategy To Construct an In-Plane ZnIn2S4/In(OH)3 Heterojunction with Enhanced CO2 Photoreduction Performance.

The in-plane heterojunctions with atomic-level thickness and chemical-bond-connected tight interfaces possess high carrier separation efficiency and fully exposed surface active sites, thus exhibiting exceptional photocatalytic performance. However, the construction of in-plane heterojunctions remains a significant challenge. Herein, we prepared an in-plane ZnIn2S4/In(OH)3 heterojunction (ZISOH) by partial conversion of ZnIn2S4 to In(OH)3 through the addition of H2O2. This in situ oxidation etching-hydrolysis approach enables the ZISOH heterojunction to not only preserve the original nanosheet morphology of ZnIn2S4 but also form an intimate interface. Moreover, generated In(OH)3 serves as an electron-accepting platform and also promotes the adsorption of CO2. As a result, the heterojunction exhibits a remarkably enhanced performance for photocatalytic CO2 reduction. The production rate and selectivity of CO reach 1760 μmol g-1 h-1 and 78%, respectively, significantly higher than those of ZnIn2S4 (842 μmol g-1 h-1 and 65%). This work puts forward a feasible and facile approach to construct in-plane heterojunctions to enhance the photocatalytic performance of two-dimensional metal sulfides.

Construction of BaTiO3-TiO2 hollow sphere heterojunctions for enhanced microwave dynamic therapy in cancer treatment.

Cancer is one of the primary health concerns among humans due to its high incidence rate and lack of effective treatment. Currently, medical techniques to achieve the precise elimination of local cancer lesions with negligible damage to normal tissues are still intensely desired. Herein, we synthesized BaTiO3-TiO2 hollow spheres (BTHSs) for use in microwave dynamic therapy (MWDT) for cancer. Under UV irradiation, BTHSs can mediate the production of multiple reactive oxygen species (ROS), mainly 1O2, which results in a rapid photocatalytic degradation rate (97%), 1.6-fold that of commercial P25. Importantly, the ROS production process can be triggered by microwaves to effectively execute MWDT for cancer. Under microwave irradiation, BTHSs exhibit a remarkable therapeutic effect and slight cytotoxicity. In terms of mechanism, the enhanced ROS production efficiency of BTHSs can be attributed to their unique hollow structure and the formation of a type-II heterojunction by the incorporation of BaTiO3. The hollow structure increases the availability of active sites and enhances light scattering, while the BaTiO3-TiO2 heterojunction enhances the photocatalytic activity of TiO2 through charge transfer and electron-hole separation. Overall, this study provides important insights into the design and optimization of sensitizers for MWDT applications.

Supercritical CH3OH-Triggered Isotype Heterojunction and Groups in g-C3N4 for Enhanced Photocatalytic H2 Evolution.

The structure tuning of bulk graphitic carbon nitride (g-C3N4) is a critical way to promote the charge carriers dynamics for enhancing photocatalytic H2-evolution activity. Exploring feasible post-treatment strategies can lead to effective structure tuning, but it still remains a great challenge. Herein, a supercritical CH3OH (ScMeOH) post-treatment strategy (250-300 °C, 8.1-11.8 MPa) is developed for the structure tuning of bulk g-C3N4. This strategy presented advantages of time-saving (less than 10 min), high yield (over 80%), and scalability due to the enhanced mass transfer and high reactivity of ScMeOH. During the ScMeOH post-treatment process, CH3OH molecules diffused into the interlayers of g-C3N4 and subsequently participated in N-methylation and hydroxylation reactions with the intralayers, resulting in a partial phase transformation from g-C3N4 into carbon nitride with a poly(heptazine imide)-like structure (Q-PHI) as well as abundant methyl and hydroxyl groups. The modified g-C3N4 showed enhanced photocatalytic activity with an H2-evolution rate 7.2 times that of pristine g-C3N4, which was attributed to the synergistic effects of the g-C3N4/Q-PHI isotype heterojunction construction, group modulation, and surface area increase. This work presents a post-treatment strategy for structure tuning of bulk g-C3N4 and serves as a case for the application of supercritical fluid technology in photocatalyst synthesis.

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.

Metal Sulfide‐Based Nanoarchitectures for Energetic and Environmental Applications

Despite their numerous excellent properties, metal sulfides are not particularly efficient at converting energy and purifying the environment, which limits their further applications. Fortunately, the energy conversion and environmental purification efficiencies of these materials have experienced notable advancements in recent years, accompanied by an improved understanding of their underlying mechanisms. Herein, progress in experimental researches in recent years on the engineering of single component metal sulfides by controlling morphology, construction of heterojunctions, and incorporating elements is reviewed. Methods to design and prepare metal sulfide‐based composites by building binary or ternary heterojunctions of metal sulfide/semiconductor/conductor are also discussed in detail. These materials are used in energy conversion and environmental purification systems, where they act as photocatalytic materials not only to split water, reduce carbon dioxide or nitrogen, but also to degrade pollutants (organic and inorganic) in water and gas. Finally, it is concluded by summarizing the research frontiers of metal sulfide nanomaterials in energy and environmental applications, as well as proposing potential challenges and future research directions. This work may contribute to a better understanding of metal sulfide nanocomposites and provide clues for the fabrication of more efficient metal sulfide‐based nanostructures for clean energy production and environmental remediation.

The construction of Cs3MoxSbyBr9/BiVO4 S-scheme heterojunction photocatalyst for efficient photocatalytic N2 fixation

Synergistic nitrogen (N2) reduction with water (H2O) oxidation is meaningful but challenging owing to the inertness of the N2 molecule and the sluggish kinetics of H2O oxidation. Herein, a simutaneous-promotion strategy of redox capacities is presented for constructing a lead-free Cs3Sb2Br9-based S-scheme heterojunction, by decorating Mo-functionalized Cs3Sb2Br9 nanocrystals (Cs3MoxSbyBr9) on BiVO4 nanosheet through an in-situ plane-to-point growth manner. The Mo-functionalization for Cs3Sb2Br9 enables the regulation of the d-band center position, greatly improving surface reaction kinetics for N2 reduction. Furthermore, the construction of the S-scheme heterojunction enhances the driving force for H2O oxidation and spatial charge separation of photocatalysts. As anticipated, the resultant Cs3MoxSbyBr9/BiVO4 exhibits an excellent photocatalytic N2 reduction activity under ambient atmosphere, achieving ammonia (NH3) production at a rate of 300 ± 5 μmol g−1 h−1 under simulated sunlight illumination (100 mW cm−2), which is nearly 20-fold higher than that of pristine Cs3Sb2Br9.

Photocatalytic activation of sodium percarbonate by C3N5/C2N3 homojunction for rapid water purification: Efficient electron transfer of built-in electric field

The sodium percarbonate (SPC) activation by photogenerated electron from metal-free semiconductors is a potential advanced oxidation process in water treatment. C2N3, a novel CxNy material, was used to construct a nonmetallic homojunction catalyst via loading C3N5. The C3N5/C2N3 homojunction catalyst was used to photocatalytic activate SPC to degrade acetaminophen (AP), sulfamethoxazole, tetracycline, oxytetracycline and acyclovir. The CN-2/SPC/Vis system can completely remove AP within 20 min at 15 °C, and achieve excellent removal rate in a wide pH range. Its reaction rate constant was 24 times higher than that of C3N5/C3N4/SPC/Vis system. The CN-2/SPC/Vis system showed outstanding removal efficiency in tap and lake water. Notably, CN-2 was prepared as a photocatalytic suspension sponge and exhibited superior practicability in secondary effluent simulation experiment. CN-2 sponge can completely degrade AP within 50 min. The dominant active species for AP removal were h+, •O2− and 1O2. DFT calculations and electrochemical experiments demonstrated that the built-in electric field of nonmetallic homojunction accelerated the carrier separation, and more photogenerated electrons activated SPC to generate ROS. This work provides new insights into the construction of heterojunction in photocatalytic system and reveals the application potential of homojunction in wastewater purification.

In situ synthesis of three-dimensional flower-like TiO2/WO3 heterojunction: Enhanced visible photocatalytic properties and theoretical calculations

The construction of heterojunction photocatalysts is an excellent strategy for treating wastewater. Herein, a three-dimensional nanoflower-like TiO2/WO3 heterojunction photocatalyst was synthesized in situ on the surface of pure Ti substrate by plasma electrolyte oxidation (PEO) combined with a subsequent process, and the abundant network topology and lattice defects improved the adsorption performance of the photocatalyst. The construction of Z-scheme heterojunction not only promotes the separation of photogenerated carriers, but also enhances the light absorption ability and greatly improves the photocatalytic performance of photocatalysts. Under the synergistic effect of adsorption and photocatalysis, the degradation rate of MB reached 86.2 % in 2 h, which was significantly higher than that of the single-component photocatalyst. Finally, the synthesis of TiO2/WO3 heterojunction photocatalysts by this process and the reaction mechanism of heterojunction photocatalysts for the degradation of organic dyes were illustrated by combining experiments and DFT calculations. In conclusion, this study opens up a new process for synthesizing Z-scheme heterojunction photocatalysts, which brings new insights for photocatalytic treatment of water pollution.

Modification strategies and applications of Mn–Cd–S solid solution-based photocatalysts

Semiconductor photocatalyzed energy production and environment treatment have received a lot of attention. Mn–Cd–S solid solutions (MnxCd1−xS) with tunable band structure, suitable redox capacity, and visible light response is recognized as one of the most promising photocatalysts for practical applications. However, low separation efficiency of photogenerated carriers and sluggish reaction kinetics restricts its photocatalytic activity. This review discusses the advantages and drawbacks of MnxCd1−xS for photocatalysis in terms of electronic band structure and surveys the modification strategies of photocatalytic activity, including modulation of Mn/Cd ratio, morphology/structure regulation, defect engineering, construction of heterojunction, loading cocatalysts, and integration of multiple strategies. Then, the progress in photocatalytic water splitting to hydrogen, carbon dioxide reduction, and pollutant degradation using MnxCd1−xS-based materials are summarized. Finally, it is concluded by outlining the challenges and opportunities for developing efficient photocatalysts based on MnxCd1−xS.

Novel high entropy alloy/NiAl2O4 photocatalysts for the degradation of tetracycline hydrochloride: Heterojunction construction, performance evaluation and mechanistic insights

Novel NiAl2O4 (NAO)/high entropy alloy (HEA) (Ti), NAO/HEA (Mn) and NAO/HEA (Mo) heterojunction photocatalysts with high photocatalytic activity for the degradation of tetracycline hydrochloride (TC) under simulated sunlight irradiation were synthesized by the polyacrylamide gel method combined with a low temperature sintering technique. The effects of environmental parameters, including drug concentration, catalyst content and pH value, on the photocatalytic activity of NAO/HEA photocatalysts were investigated in detail on the basis of the response surface methodology (RSM) and experimental results. The optimal initial TC concentration, catalyst content, and pH were 100 mg/L, 1 g/L, and 5, respectively. The photocatalytic activity of NAO/HEA photocatalyst (84.6 %) was significantly improved compared to the degradation percentage of HEA (Ti) photocatalyst (36.5 %). The roles of active free radicals including h+, •O2−, •OH and oxygen vacancy in photocatalysis were verified using multiple characterization methods. In-depth analysis was conducted on the degradation pathway of TC, the safety of degradation intermediates, and the photocatalytic mechanism of NAO/HEA (Ti) photocatalyst. The Z - scheme heterojunction can significantly improve the transport efficiency of photogenerated carriers and inhibit the recombination rate of electron hole pairs in the system, which provides a new idea for exploring the application of new HEA - based heterojunction photocatalysts in the field of photocatalysis.

Construction of Z-scheme heterojunction ZIF-8-decorated ZnO/SiO2 for enhanced visible-light photocatalytic removal of organic pollutants and reduction of Cr (VI)

The zeolitic imidazolate framework-8 (ZIF-8) demonstrates promising photocatalytic activity in wastewater treatment. Nevertheless, limited visible light utilization and arduous recyclability hinder its practical application. Herein, we fabricated ZIF-8 decorated zinc oxide/silica (ZnO/SiO2) hollow spheres by an in-situ strategy. This composite effectively photocatalytically degrades organic dyes and reduces Cr (VI) under the simulated sunlight. Results reveal that Z-scheme heterojunction construction between ZIF-8 and ZnO/SiO2 is formed and facilitates the effective separation and transport of electrons and holes, leading to nearly complete methylene blue (MB) degradation, 88.7 % of rhodamine B (RhB) removal, and 41.8 % Cr (VI) reduction within 30 min. Notably, the ZIF-8/ZnO/SiO2 composite exhibits enhanced visible-light utilization attributed to its reduced band gap (3.04 eV), thereby improving MB degradation compared to using solely ultraviolet light. Furthermore, the composite demonstrates remarkable reusability and stability, achieving over 99 % removal rate for MB after four photocatalysis cycles with minimal structural and morphological changes. This work demonstrates the remarkable photocatalytic activity ZIF-8/ZnO/SiO2 with its improved visible-light response, highlighting the potential of using modified ZIF-8 materials as promising and sustainable catalysts for wastewater treatment.

Hollow heterojunction with dual-vacancy engineering to boost photocatalytic performance for photoreduction of CO2 coupled with selective oxidation of benzyl alcohol to benzaldehyde

CO2 photoreduction into chemical fuels is hopeful and sustainable for a carbon–neutral future. Herein, a bifunctional dual-vacancy-modified hollow heterojunction photocatalyst is ingeniously designed for CO2 photoreduction to CO coupling with selective oxidation of benzyl alcohol to benzaldehyde. Synergistic catalysis effect resulted from hollow heterostructures, TiO2 with O vacancies (TiO2-x) and Zn0.3-xCd0.7S with Zn vacancies (ZCS) leads to excellent photoreduction and photoxidation performances. The optimized sample (TiO2-x/ZCS hollow sphere) exhibits highest photocatalytic activity of all the obtained samples. The yields of CO and benzaldehyde are 105 and 323.5 μmol g–1h−1, respectively. The construction of Z-scheme heterojunction realizes the spatial separation of redox reaction sites, and the dual-vacancy distributed on the heterojunction enhance the interfacial reactivity. Additionally, density functional theory calculation and in-situ technology reveal that Zn vacancy in ZCS and O vacancy in TiO2-x function as active sites for the binding and activation of *COOH and *PhCH2O-, respectively, thereby stabilizing the crucial step in the formation of intermediates such as CO and benzaldehyde. This work enhances the utilization of photogenerated carrier, and affords a new opportunity to design hollow heterojunction with dual-vacancy engineering to boost photocatalytic performance for coupling reaction system.

Promoting charge separation in CuInS2/CeO2 photocatalysts by an S-scheme heterojunction for enhanced photocatalytic H2 production

Low charge separation efficiency significantly hampers the performance of photocatalytic hydrogen production. Constructing heterojunctions emerges as a crucial strategy to enhance photocatalytic activity by improving charge separation. An S-scheme heterojunction not only effectively separates the photogenerated charge in composite photocatalysts but also preserves optimal redox capabilities. This study presents the first report of CuInS2/CeO2 (CIS/CeO2) and demonstrates how charge separation within CIS/CeO2 to enhance photocatalytic hydrogen production through the construction of an S-scheme heterojunction. The UV–visible-driven hydrogen production rate of CIS/CeO2 is 4.6 and 9.4 times higher than that of CIS and CeO2 alone, respectively. The improved photocatalytic performance primarily stems from enhanced charge separation promoted by the S-scheme heterojunction. The charge transfer pathway was confirmed as an S-scheme mechanism through a combination of band structure experiments, density functional theory (DFT) calculations on work function, internal electric field, and charge differential density distribution, alongside electron paramagnetic resonance (EPR) experiments. Multiple perspectives were employed to elucidate the reasons behind facilitating efficient charge separation. This research provides valuable insights for advancing photocatalytic performance.

Modulating band structure of g-C3N4 by doping oxygen to transform FeCo2O4/g-C3N4 heterojunction from type-II to S-scheme for enhancing photo-Fenton-like reaction

Constructing S-scheme heterojunctions is a highly prevalent approach in enhancing the activation efficiency of peroxymonosulfate (PMS). However, the two semiconductors that have the potential to form S-scheme heterojunction (such as FeCo2O4 and carbon nitride) typically tend to form type-II heterojunction. In this study, through oxalic acid assisted oxygen atom doping in carbon nitride, followed by the utilization of oxygen-doped carbon nitride (O-CN) as precursors in combination with cobalt chloride and iron chloride, the final synthesis of a novel composite catalyst is achieved. The introduction of oxygen atoms into the graphite carbon nitride can lead to an overall reduction in the band structure, facilitating the controlled transformation of a type-II heterojunction to an S-scheme heterojunction. This transformation is confirmed through density functional theory (DFT) calculations and electron spin resonance (ESR) tests. In the photo-Fenton-like system, the 15% FeCo2O4/Oxygen doped-C3N4 (FCOCN) catalyst demonstrated a remarkable degradation efficiency of 93.5% for tetracycline hydrochloride (TCH). This efficiency surpassed that of O-CN (47.8%) and FeCo2O4 (60.3%). Furthermore, the degradation efficiency of the 15% FCOCN catalyst was significantly higher than that of photocatalysis (2.04 times greater) and Fenton-like treatment (1.11 times greater). Remarkably, within a short period of 14min, the emerging contaminants, including sulfamethoxazole (SMX), bisphenol A (BPA), and carbamazepine (CBZ), were completely degraded. Atrazine (ATZ) showed a remarkable degradation rate of 77.1%. This study offers valuable insights into the construction of S-scheme heterojunction through the manipulation of band structure in type-II heterojunction by oxygen doping.

TiO2–Cu7S4 modified with a carbazole-based conjugated porous polymer for adsorption and photocatalytic degradation of bisphenol A

Adsorption-photocatalytic degradation of organic pollutants in water is an advantageous method for environmental purification. Herein, a feasible strategy is developed to construct a novel dual S-scheme heterojunctions Cu7S4–TiO2-conjugated polymer with a donor–acceptor structure. There are abundant adsorption active sites for adsorption in the porous structure of the composites, which can rapidly capture pollutants through hydrogen bonding and π-π interactions. In addition, the dual S-scheme heterojunctions effectively improve carrier separation while maintaining a strong redox ability. Thus, the optimized 1.5% CST-130 catalysts can adsorb 71% of 20 ppm BPA in 15 min and completely remove it within 30 min with high adsorption capacity and photodegradation efficiency. Therefore, this study provides a new inspiration for synergistic adsorption and degradation of BPA and the construction of dual S-scheme heterojunction.

In situ construction of core-shell NiFe-LDH@ZnIn2S4 direct Z-scheme heterojunction for facilitating photocatalytic H2 evolution

The development of photocatalysts with non-noble metals and the effective separation of photoexcited carriers is a significant strategy for accelerating surface reaction kinetics and promoting water splitting to produce H2. Herein, an exquisite core-shell NiFe-LDH@ZnIn2S4 heterojunction photocatalyst was constructed by in situ decoration of ultrathin ZnIn2S4 nanosheets on the surface of the flower-like NiFe-LDH microsphere. The synthesized 3D hierarchical NiFe@ZIS-25 composite exhibits enhanced photocatalytic H2 evolution activity, reaching 9.12mmol·h-1·g-1, which is 2.52-fold higher than pure ZnIn2S4. The significant improvement in H2 evolution performance could be attributed to the hierarchical core-shell structure of the NiFe@ZIS-25 photocatalyst, which enhanced the light capture ability. In addition, the interfacial coupling effect of ZnIn2S4 and NiFe-LDH is beneficial to the migration of carriers. More importantly, the construction of Z-scheme heterojunction efficiently promotes the fast translation of photogenerated carriers while preserving a stronger reduction potential to achieve H2 evolution. This work elucidates a rational strategy to develop efficient photocatalysts with hierarchical core-shell structures for water splitting.