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TiO2 is a widely used photoelectric conversion semiconductor material. However, due to its native defects, such as the selective absorption of ultraviolet light and high recombination rate of photogenerated carriers, it exhibits poor photoelectrochemical (PEC) water splitting performance. In this study, intrinsic defect titanium vacancy and semiconductor recombination agents ZnIn2S4 were introduced into an anodization‐annealed TiO2 film (TiO2 NT) to enhance the photoanode activity. The activity‐enhanced TiO2 photoanode (ZIS@TiO2 NT‐EA) was characterized by surface analyses and photoelectrochemical measurements. Mott‐Schottky measurement indicated that the introduction of titanium vacancies into the TiO2 NT changed its semiconductor type from n to p, and significantly reduced its apparent activation energy if compared with the TiO2 NT. In addition, after the ZnIn2S4 nanoparticles were loaded on the TiO2 NT‐EA film, the carrier concentration of the ZIS@TiO2 NT‐EA was nearly 12 times higher than the pristine TiO2 NT. Due to the higher carrier separation efficiency resulting from the formation of p‐n heterojunction between TiO2 and ZnIn2S4, the photocurrent density of the ZIS@TiO2 NT‐EA reached 3.89 mA cm−2 at 1.23 V (vs. RHE), nearly 3 times higher than that of the original TiO2 NT. Amazingly, the maximum applied bias photon‐to‐current efficiency (ABPE) value of the ZIS@TiO2 NT‐EA photoanode reached 2.15 % at 0.496 V (vs. RHE), which is very competitive if compared with all the reported TiO2 film electrodes in the PEC water splitting application. The incident photon‐to current efficiency (IPCE) of the ZIS@TiO2 NT‐EA photoanode was approximately 40.9% at 300 nm, which was about 3 times higher than that of the TiO2 NT (13.6%). To understand these impressive improvements in water splitting, further analyses were conducted on the effect of the increased titanium vacancy concentration in the TiO2 lattice and the formation of p‐n junction between the TiO2 and ZnIn2S4 on the PEC behaviour, as well as on the charge transfer resistance and separation efficiency of carriers. [ABSTRACT FROM AUTHOR]

[Display omitted] • Construction of octagonal 2D nanoplates with large specific surface area exposes more active sites and accelerates mass transfer for improved OER performance. • The formation of p-n heterojunction between FeP and CoP induces the generation of embedded electric field, optimizes the electronic structure, and improves the intrinsic activity of OER. • DFT calculations confirm the existence of charge transfer at the heterojunction interface and effectively optimize the Gibbs free energy of the OER. Surface reconstruction of electrocatalysts is an effective strategy to modulate the space charge distribution to enhance the electrocatalytic activity. The p-n heterostructured FeP/CoP-2D octagonal nanoplates were successfully constructed by cation-exchange method. The space charge effect caused by the p-n heterojunction accelerated the electron transfer, optimized the electronic structure, and improved the activity of the active sites during the oxygen evolution reaction process. As a result, FeP/CoP-2D required only 247 mV overpotential to achieve a current density of 10 mA cm−2 with a Tafel slope as low as 68 mV dec-1. Density-functional theory calculations confirmed that the construction of p-n heterojunctions can enhance the adsorption of *OH in the active centers and optimize the Gibbs free energy of the OER reaction. This study provides an effective and feasible strategy for constructing p-n heterojunctions to modulate the space charge state for optimizing the OER performance of electrocatalysts. [ABSTRACT FROM AUTHOR]

Star-like BiVO4 and Cu2O nanocubes were prepared by hydrothermal method and chemical reduction, respectively, and Cu2O/BiVO4 p-n heterojunction with different mass ratios of Cu2O to BiVO4 (3:1, 1:1, 1:3) were synthesized via facile physical mixing. The as-synthesized samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflection spectroscopy (DRS) and X-ray photoelectron spectroscopy (XPS). The photocatalytic performance of the Cu2O/BiVO4 composites was evaluated by degradation of tetracycline hydrochloride (TC) under simulated solar illumination. Owing to the fast charge transfer between n-type BiVO4 and p-type Cu2O, Cu2O/BiVO4 composites exhibited superior photocatalytic activity. When the mass ratio of Cu2O to BiVO4 was 1:3, the highest degradation efficiency of TC reached 78.9% within 24 min. [ABSTRACT FROM AUTHOR]

The synergism of multi-electric field modulation and interfacial chemical bond bridging expedites the vectorial charge separation and migration kinetic for efficient photocatalysis over S O bonded 0D Ag 2 S/2D Bi 4 TaO 8 Cl p-n oriented heterojunction. [Display omitted] • S O bonded 0D Ag 2 S/2D Bi 4 TaO 8 Cl p-n oriented heterostructure is constructed. • Double inner electric fields deliver powerful driving forces for charge separation. • Interfacial S O bond serves as atomic-level channel for promoting charge transfer. • Oriented heterojunction shows brilliant redox activity for TC and Cr(VI) removal. • Detailed photocatalytic mechanisms, degradation pathway and toxicity were proposed. Heterojunctions have been proved to be the promising photocatalysts for hazardous contaminants removal, but the inferior interfacial contact, low carrier mobility and random carrier diffusion seriously hamper the photoactivity improvement of the conventional heterojunctions. Herein, S O chemically bonded p-n oriented heterostructure is fabricated via selectively anchoring of p-type Ag 2 S nanoparticles on the lateral facet of n -type Bi 4 TaO 8 Cl nanosheet. Such a p-n heterojunction engineering on specific facet of Bi 4 TaO 8 Cl semiconductor derives ingenious double internal electric field (IEF), which not only effectively creates the spatially separated oxidation and reduction sites, but also delivers the powerful driving forces for impactful spatial directed photocarrier transfer along the cascade path. Additionally, our experimental and theoretical analyses jointly signify that the interfacial S O bond could serve as an efficient atomic-level interfacial channel, which is conducive to encouraging the vectorial charge separation and migration kinetic. As a result, the Ag 2 S/Bi 4 TaO 8 Cl oriented heterojunction exhibits significantly enhanced visible light driven photocatalytic redox ability for tetracycline oxidation and hexavalent chromium reduction than those of single component and the traditional random/mixed heterojunctions. This study could provide a deeper insight into the synergistic effects of multi-IEF modulation and interfacial chemical bond bridging on optimizing the photogenerated carrier behaviors. [ABSTRACT FROM AUTHOR]

[Display omitted] Hollow structure hybrids have gained considerable attention for their ability to reduce CO 2 owing to their rich active sites, high gas adsorption ability, and excellent light utilization capacity. Herein, a template-engaged strategy was provided to fabricate copper sulphide@cerium dioxide (CuS@CeO 2) p-n heterojunction hollow cube photocatalysts using Cu 2 O cubes as a sacrificial template. The sequential steps of loading of CeO 2 nanolayer, sulfidation, and etching reaction facilitate the formation of CuS@CeO 2 p-n heterojunction hollow cubes. Compared with the single CuS, CeO 2 , and their physical mixture, the CuS@CeO 2 p-n heterojunction hollow cube photocatalyst expresses a higher performance toward photocatalytic CO 2 reduction under solid–gas reaction conditions due to the faster separation of photogenerated charges. The further enhanced performance of CuS@CeO 2 p-n heterojunction hollow cubes was achieved by decorating pt nanoparticles due to the fact that Pt nanoparticles had a high electron affinity and CO 2 adsorption capacity, and the highest CO and CH 4 yields of the optimized hybrid reached 195.8 μmol g-1 h−1 and 19.96 μmol g-1 h−1, respectively. This work might provide a strategy for designing and synthesizing efficient hollow heterostructured photocatalysts for solar energy conversion and utilization. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel binary CuS/NaNbO 3 -nanorod hierarchical photocatalysts were designed using a facile method. • Obvious structure–activity relationship and superior structural and chemical stability. • 40%CuS/NaNbO 3 reached an H 2 rate of 1603 µmol·g−1·h−1 (20 mg), 3.6 and 2.7 times higher than NaNbO 3 and CuS. • P N heterojunction and effect of co-catalyst promoted the charge transfer. The construction of heterojunctions is commonly regarded as an efficient way to promote the production of hydrogen via photocatalytic water splitting through the enhancement of interfacial interactions. The p-n heterojunction is an important kind of heterojunction with an inner electric field based on the different properties of semiconductors. In this work, we reported the synthesis of a novel CuS/NaNbO 3 p-n heterojunction by depositing CuS nanoparticles on the external surface of NaNbO 3 nanorods, using a facile calcination and hydrothermal method. Through the screening of different ratios, the optimum hydrogen production activity reached 1603 μmol·g−1·h−1, which is much higher than that of NaNbO 3 (3.6 times) and CuS (2.7 times). Subsequent characterizations proved semiconductor properties and the existence of p-n heterojunction interactions between the two materials, which inhibited the recombination of photogenerated carriers and improved the efficiency of electron transfer. This work provides a meaningful strategy to utilize the p-n heterojunction structure for the promotion of photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]

The 2D MoS2 with superior optoelectronic properties such as high charge mobility and broadband photoresponse has attracted broad research interests in photodetectors (PD). However, due to the atomic thin layer of 2D MoS2, its pure photodetectors usually suffer from inevitable drawbacks such as large dark current, and intrinsically slow response time. Herein, a new organic material BTP‐4F with high mobility is successfully stacked with 2D MoS2 film to form an integrated 2D MoS2/organic P–N heterojunction, facilitating efficient charge transfer as well as significantly suppressed dark current. As a result, the as‐obtained 2D MoS2/organic (PD) has exhibited excellent response and fast response time of 332/274 µs. The analysis validated photogenerated electron transition from this monolayer MoS2 to subsequent BTP‐4F film, whereas the transited electron is originated from the A− exciton of 2D MoS2 by temperature‐dependent photoluminescent analysis. The ultrafast charge transfer time of ≈0.24 ps measured by time‐resolved transient absorption spectrum is beneficial for efficient electron–hole pair separation, greatly contributing to the obtained fast photoresponse time of 332/274 µs. This work can open a promising window to acquire low‐cost and high‐speed (PD). [ABSTRACT FROM AUTHOR]

Fabricating an efficient photocatalyst for solving energy and environmental pollution is challenging, especially using sunlight. Herein, a photocatalyst was developed to degrade plasticizer (Bisphenol A, BPA) and an industrial‐pollutant 2,4‐dinitrophenol (DNP) found in water bodies with sunlight. Several ZnIn2S4/B‐doped g‐C3N4 (ZIS@BCN) heterojunctions were prepared by an ultra‐sonochemical route followed by calcination. HRTEM, MS analysis, EIS, photocurrent, and synergic factor calculations were employed to confirm p‐n heterojunction. The phase purity and optical characteristics of the photocatalysts were determined by XRD, PL, and DRS UV‐Vis spectroscopy. A successful p‐n heterojunction 2 %ZIS@BCN showed better degradation efficiency than pristine ZIS (n‐type) and BCN (p‐type) semiconductors. Moreover, the best photocatalyst (2 % ZIS@BCN) exhibited maximum photo‐degradation of 83 % of BPA and 85 % of DNP under solar light illumination. The degradation pathways and involvement of reactive species were confirmed using LC–MS, trapping experiments, nitroblue‐tetrazolium, and terephthalic acid tests. The superior activity is ascribed to the successful formation of an electrical double layer (EDL) between p‐type BCN and n‐type ZIS, which minimizes the e−‐h+ recombination and thereby increases the visible light utilization efficiency. The work validates the formation of ZIS@BCN p‐n heterojunction, showing solar light‐driven photocatalytic degradation of toxic effluents found in water bodies. [ABSTRACT FROM AUTHOR]

Abstract The 2D MoS2 with superior optoelectronic properties such as high charge mobility and broadband photoresponse has attracted broad research interests in photodetectors (PD). However, due to the atomic thin layer of 2D MoS2, its pure photodetectors usually suffer from inevitable drawbacks such as large dark current, and intrinsically slow response time. Herein, a new organic material BTP‐4F with high mobility is successfully stacked with 2D MoS2 film to form an integrated 2D MoS2/organic P–N heterojunction, facilitating efficient charge transfer as well as significantly suppressed dark current. As a result, the as‐obtained 2D MoS2/organic (PD) has exhibited excellent response and fast response time of 332/274 µs. The analysis validated photogenerated electron transition from this monolayer MoS2 to subsequent BTP‐4F film, whereas the transited electron is originated from the A− exciton of 2D MoS2 by temperature‐dependent photoluminescent analysis. The ultrafast charge transfer time of ≈0.24 ps measured by time‐resolved transient absorption spectrum is beneficial for efficient electron–hole pair separation, greatly contributing to the obtained fast photoresponse time of 332/274 µs. This work can open a promising window to acquire low‐cost and high‐speed (PD).

• The hierarchical CuS@SnS 2 p-n heterojunction hollow cubes were fabricated. • The synergy of hollow cubes and p-n heterojunction enhanced photocatalytic CO 2 reduction. • The addition of Au nanoparticles was conducive to binding and reducing CO 2 molecules. • The synergy of p-n heterojunction and Schottky junction accelerated charge transfer and separation. During the photocatalytic CO 2 reduction process, fast charge transport, abundant active sites, and high visible light utilization in photocatalysts are key to achieving excellent CO 2 conversion efficiency. In this work, we have designed and prepared hierarchical CuS@SnS 2 p-n heterostructure hollow cubes for photocatalytic CO 2 reduction. First, a monolayer of CuS was in situ generated on the pre-prepared Cu 2 O cubes to construct core–shell Cu 2 O@CuS cubes by sulfidation of Cu 2 O cubes. The following etching process led to the formation of CuS hollow cubes. Finally, the hierarchical CuS@SnS 2 p-n heterostructure hollow cubes were obtained by growing SnS 2 nanosheets on the CuS hollow cubes. The prepared CuS@SnS 2 p-n heterostructure hollow cubes showed an improved photocatalytic CO 2 reduction activity compared with the bare CuS and SnS 2 control samples. The p-n heterojunction formed between SnS 2 and CuS as well as its hollow structure enhanced the charge carrier separation efficiency and the light absorption capacity of the hybrid catalyst. Furthermore, after the decoration of Au nanoparticles, the formed Schottky junction further discouraged the charge carrier recombination. Thus, the cooperative p-n heterojunction and Schottky junction greatly facilitated photocatalytic CO 2 reduction, and exhibiting the maximum CO and CH 4 yields of 140.1 and 77.5 μmol g−1 h−1, respectively. This work presents an efficient design of high-performance catalysts for photocatalytic CO 2 reduction. [ABSTRACT FROM AUTHOR]

Photocatalysts have focused on scientific endeavors for five decades already. Their ability to generate solar fuel via relatively environmentally benign processes brings promises of a future with increasingly sustainable energy production. A class of materials, heterojunction (HJ) semiconductors, have immense potential due to their versatility, stability, and cost‐effectiveness. In addition, meticulous engineering of p‐n HJ enables the apparition of an electric field at the junction, a supplementary driving force that drives the charge carriers to separate effectively upon illumination. Therefore, we combined n‐type carbon nitride with p‐type CuGaO2 to form a photo‐active p‐n HJ. Mechanistic insights being highly sought‐after, we then employed X‐ray photoelectron spectroscopy and X‐ray absorption spectroscopy as complementary and orbital‐specific techniques to probe the changes caused by interfacing CuGaO2 with g‐C3N4. [ABSTRACT FROM AUTHOR]

Photocatalysts have focused on scientific endeavors for five decades already. Their ability to generate solar fuel via relatively environmentally benign processes brings promises of a future with increasingly sustainable energy production. A class of materials, heterojunction (HJ) semiconductors, have immense potential due to their versatility, stability, and cost‐effectiveness. In addition, meticulous engineering of p‐n HJ enables the apparition of an electric field at the junction, a supplementary driving force that drives the charge carriers to separate effectively upon illumination. Therefore, we combined n‐type carbon nitride with p‐type CuGaO2 to form a photo‐active p‐n HJ. Mechanistic insights being highly sought‐after, we then employed X‐ray photoelectron spectroscopy and X‐ray absorption spectroscopy as complementary and orbital‐specific techniques to probe the changes caused by interfacing CuGaO2 with g‐C3N4. [ABSTRACT FROM AUTHOR]

Summary: The imidazolium salt zeolite framework (ZIFs) organometallic framework materials have the advantages of high stability and controllable structure and are excellent materials for preparing photocatalytic semiconductors. In this study, the regular dodecahedron material ZIF‐67 was used as the substrate, and the intermediate was calcined after the substrate adsorbed Co‐based metal clusters to obtain Co3O4 with a hollow double‐shell structure. Through SEM and fluorescence detection, it can be seen that the Co3O4 material obtained by this method not only has a unique spatial morphology but also shows a strong light absorption performance and a high charge transfer rate. In addition, graphite‐like phase carbon nitride (g‐C3N4), as a traditional catalyst, has been unable to move toward industrialization due to its low electron utilization and light absorption properties. So here, the composite catalyst CNCO‐x (x = 1, 2, 2, 3, 4, and 5) was prepared by simply anchoring Co3O4 and g‐C3N4 to improve the catalytic performance of g‐C3N4. The results show that the introduction of Co3O4 not only improves the electron utilization of g‐C3N4 but forms a charge transfer bridge channel (p‐n heterojunction) after contact between the two, which effectively promotes the rapid transfer of photoelectrons between the contact interfaces. Finally, when the amount of Co3O4 introduced is 15%, the amount of hydrogen produced in 5 hours can reach 0.163 mmol (3.26 mmol g−1 hour−1), which is 163 times that of pure g‐C3N4. [ABSTRACT FROM AUTHOR]

Surface enhanced Raman scattering (SERS) based on chemical mechanism (CM) attracts tremendous attention for great selectivity and stability. However, low enhancement factor (EF) limits its practical applications for trace detection. Here, a novel sponge‐like Cu‐doping SnO2‐NiO p‐n semiconductor heterostructure (SnO2‐NiOx/Cu), was first created as a CM‐based SERS substrate with a significant EF of 1.46×1010. This remarkable EF was mainly attributed to the enhanced charge‐separation efficacy of p‐n heterojunction and charge transfer resonance resulted from Cu doping. Moreover, the porous structure enriched the probe molecules, resulting in further SERS signals magnification. By immobilizing CuPc as an inner‐reference element, SnO2‐NiOx/Cu was developed as a SERS nose for selective recognition of multiple lung cancer related VOCs down to ppb level. The information of VOCs was recorded in a barcode, demonstrating practical potential of a desktop SERS device for biomarker screening. [ABSTRACT FROM AUTHOR]

The rational design of durable and nonprecious nanocomposite photocatalysts with efficient charge separation and abundant active sites is still a grand challenge for photocatalytic hydrogen production from water reduction. Herein, a novel ternary nanocomposite, MoO 2 decorated Mn 0.5 Cd 0.5 S/Cu 2 O p-n heterojunction has been constructed via a facile two-step route employing the energy band engineering theory. Impressively, the optimized ternary Mn 0.5 Cd 0.5 S/Cu 2 O/MoO 2 nanocomposite displays a robust photocatalytic H 2 -evolution rate of 733.24 μmol h−1 under simulated solar light irradiation, more 4.2 times higher than pure Mn 0.5 Cd 0.5 S. The results demonstrated that the p-n heterojunction formed between n-type Mn 0.5 Cd 0.5 S and p-type Cu 2 O could markedly promote the interfacial charge transfer/separation through the internal electric field, whereas the MoO 2 cocatalyst with low overpotential could effectively collect photoinduced electrons and dramatically facilitate the H 2 -evolution kinetics. Moreover, both Cu 2 O and MoO 2 could improve the light-harvesting ability of pristine Mn 0.5 Cd 0.5 S, further contributing to the boosted hydrogen generation activity. [Display omitted] • MoO 2 decorated Mn 0.5 Cd 0.5 S/Cu 2 O p-n heterojunction synthesized for H 2 -production. • Multichannel charge-carrier transfer between Mn 0.5 Cd 0.5 S, Cu 2 O and MoO 2 discussed. • High H 2 -production rate achieved over composite, 4.2 folds higher than Mn 0.5 Cd 0.5 S. [ABSTRACT FROM AUTHOR]

Electron density modulation is of great importance in an attempt to achieve highly active electrocatalysts for the oxygen evolution reaction (OER). Here, the successful construction of CuO@CoOOH p‐n heterojunction (i.e., p‐type CuO and n‐type CoOOH) nanoarray electrocatalyst through an in situ anodic oxidation of CuO@CoSx on copper foam is reported. The p‐n heterojunction can remarkably modify the electronic properties of the space‐charge region and facilitate the electron transfer. Moreover, in situ Raman study reveals the generation of SO42− from CoSx oxidation, and electron cloud density distribution and density functional theory calculation suggest that surface‐adsorbed SO42− can facilitate the OER process by enhancing the adsorption of OH−. The positively charged CoOOH in the space‐charge region can significantly enhance the OER activity. As a result, the CuO@CoOOH p‐n heterojunction shows significantly enhanced OER performance with a low overpotential of 186 mV to afford a current density of 10 mA cm−2. The successful preparation of a large scale (14 × 25 cm2) sample demonstrates the possibility of promoting the catalyst to industrial‐scale production. This study offers new insights into the design and fabrication of non‐noble metal‐based p‐n heterojunction electrocatalysts as effective catalytic materials for energy storage and conversion. [ABSTRACT FROM AUTHOR]

In this research work, p-n heterojunction Cu 2 SnS 3 /Ti3+-TiO 2 photocatalysts were synthesized by using a facile hydrothermal method to degrade tetracycline and produce hydrogen energy. The properties of Cu 2 SnS 3 /Ti3+-TiO 2 was analyzed by using XRD, SEM, TEM, HRTEM, BET, PL and UV–vis characterization. The HPLC-MS and TOC analyzer systems were used to analyze the intermediate products during the photocatalysis deprivation and total organic carbon. The characterizations showed that the addition of self-doped Ti3+ and Cu 2 SnS 3 into TiO 2 enhanced the material's crystallinity, increased the absorption region from 450 nm to 750 nm, increased the surface area of the material from 234 to 583 m2/g and reduced the recombination of charge carriers. Under visible light irradiation, Cu 2 SnS 3 /Ti3+-TiO 2 exhibited excellent degradation performance and stability. The increase in the efficiency of the material is due to the creation of an internal electric field induced by the p-n heterojunction and reduction in the bandgap of the material, which efficiently reduced the rate of recombination, increased the surface area for light absorption and increased the transfer of charge carriers. The Cu 2 SnS 3 /Ti3+-TiO 2 photocatalyst degraded 100 % tetracycline and produced 510 μmol/hg hydrogen energy. The Cu 2 SnS 3 /Ti3+-TiO 2 composite exhibited good stability even after six cycles Cu 2 SnS 3 /Ti3+-TiO 2 degraded 98–99 % TC under visible light irridiation. The efficiency of Cu 2 SnS 3 /Ti3+-TiO 2 was also analyzed in the outdoor environment, confirming that this material can be effectively used in practical applications. [ABSTRACT FROM AUTHOR]

Cu 2 O nanoparticles have been anchored on the surface of Bi 4 O 5 Br 2 hollow nanocubes, and the resulting composites have been tested for the photocatalytic degradation of organic dyes under visible light. The as-synthesized composites are composed of Bi 4 O 5 Br 2 in the monoclinic phase and Cu 2 O in the cubic phase, both of which respond to visible light. The optimized Bi 4 O 5 Br 2 /Cu 2 O composite can decompose 95% of initial RhB and 99% of initial MB after 80 min illumination, which is significantly higher than those obtained on bare Bi 4 O 5 Br 2 and Cu 2 O photocatalysts. The charge transfer and separation dynamics in the Bi 4 O 5 Br 2 /Cu 2 O composite photocatalysts under excitation are proved to be superior compared to bare Bi 4 O 5 Br 2 in the electrochemical measurements. The enhanced performance of the Bi 4 O 5 Br 2 /Cu 2 O composite is attributed to the p-n junction formed between Bi 4 O 5 Br 2 and Cu 2 O, which inhibits charge recombination and facilitates effective charge separation. Lastly, it has been proved in the scavenger tests that superoxide radical is the most crucial active species in the photocatalytic degradation of RhB. [ABSTRACT FROM AUTHOR]

Abstract Methicillin‐resistant Staphylococcus aureus (MRSA) biofilm infections after orthopedic implant increase the risk of failure and potentially cause amputation of limbs or life‐threatening sepsis in severe cases. Additionally, satisfactory bone‐implant integration is another important indicator of an ideal implant. Here, an antibiotic‐free antibacterial nanofilm based on oxide perovskite‐type calcium titanate (CTO)/fibrous red phosphorus (RP) on titanium implant surface (Ti‐CTO/RP) in which the P–N heterojunction and internal electric field are established at the heterointerface, is designed. Near‐infrared light‐excited electron–hole pairs are effectively separated and transferred through the synergism of the internal electric field and band offset, which strongly boosts the photocatalytic eradication of MRSA biofilms by reactive oxygen species with an efficacy of 99.42% ± 0.22% in vivo. Additionally, the charge transfer endows the heterostructure with hyperthermia to assist biofilm eradication. Furthermore, CTO/RP nanofilm provides a superior biocompatible and osteoconductive platform that enables the proliferation and osteogenic differentiation of mesenchymal stem cells, thus contributing to the subsequent implant‐to‐bone osseointegration after eradicating MRSA biofilms.

Methicillin‐resistant Staphylococcus aureus (MRSA) biofilm infections after orthopedic implant increase the risk of failure and potentially cause amputation of limbs or life‐threatening sepsis in severe cases. Additionally, satisfactory bone‐implant integration is another important indicator of an ideal implant. Here, an antibiotic‐free antibacterial nanofilm based on oxide perovskite‐type calcium titanate (CTO)/fibrous red phosphorus (RP) on titanium implant surface (Ti‐CTO/RP) in which the P–N heterojunction and internal electric field are established at the heterointerface, is designed. Near‐infrared light‐excited electron–hole pairs are effectively separated and transferred through the synergism of the internal electric field and band offset, which strongly boosts the photocatalytic eradication of MRSA biofilms by reactive oxygen species with an efficacy of 99.42% ± 0.22% in vivo. Additionally, the charge transfer endows the heterostructure with hyperthermia to assist biofilm eradication. Furthermore, CTO/RP nanofilm provides a superior biocompatible and osteoconductive platform that enables the proliferation and osteogenic differentiation of mesenchymal stem cells, thus contributing to the subsequent implant‐to‐bone osseointegration after eradicating MRSA biofilms. [ABSTRACT FROM AUTHOR]

Developing a highly desirable multicomponent photocatalytic system for environmental remediation and water splitting is needed for current societal development. A visible active B-rGO/ZnFe 2 O 4 photocatalyst was synthesized through the hydrothermal process, further magnify its electronic properties, the binary hybrid is modified with polypyrrole. The designed ternary hybrid utilizes the combining benefits of photo-sensitizer and interfacial charge transfer mechanism that ultimately boost its photocatalytic efficiency. The establishment of interfacial p-n heterojunction via band-bending mechanism between B-rGO (BG) nanosheets and ZnFe 2 O 4 (ZnF) nanoparticles was validated from photo-density in the opposite direction and upturned V-shaped Mott-Schottky plots. It was observed that 2BG/ZnF@20PPY exhibits the best activity i.e., 100% reduction of 50 ppm Cr (VI) in 45 min and H 2 -production of 598 μmolh−1. Effective charge separation in 2BG/ZnF@20PPY is well supported by PL, TRPL, EIS, transient-photocurrent, and donor density calculations. The strong contact among the constituents in 2BG/ZnF@20PPY is well-correlated with XPS and Raman characterization. Photocatalyst is a new emerging green technology that utilizes photons to deal with organic and inorganic pollutants along with pathogenic biological organisms. This schematic representation displays the flow of electrons and photo-reduction of a lethal metal like Cr (VI) to Cr (III) and H 2 evolution along with dis-infection of most occurring pathogenic bacteria (E. coli) by 2BG/ZnF@20PPY photocatalyst. [Display omitted] • An approach to synthesize 2BG/ZnF@20PPY for Cr (VI) and H 2 O reduction. • 2BG/ZnF@20PPY was synthesized hydrothermally followed by polymerization. • The anodic and cathodic current of 2BG/ZnF was improved after the addition of PPY. • The sensitizer in p-n heterojunction facilitates charge anti-recombination process. • The 2BG/ZnF@20PPY shows highest activity compared to n-type ZnF and p-type B-rGO. [ABSTRACT FROM AUTHOR]

Schottky junction and p-n heterojunction are widely employed to enhance the charge transfer during the photocatalysis process. Herein, Cu and Cu 3 P co-modified TiO 2 nanosheet hybrid (Cu–Cu 3 P/TiO 2) was fabricated using an in situ hydrothermal method. The ternary composite achieved the superior H 2 evolution rate of 6915.7 μmol g−1 h−1 under simulated sunlight, which was higher than that of Cu/TiO 2 (4643.4 μmol g−1 h−1) and Cu 3 P/TiO 2 (6315.8 μmol g−1 h−1) and pure TiO 2 (415.7 μmol g−1 h−1). The enhanced activity can be attributed to the collaboration effect of Schottky junction and p-n heterojunction among Cu/TiO 2 and Cu 3 P/TiO 2 , which can harvest the visible light, reduce the recombination of charge carriers and lower the overpotential of H 2 evolution, leading to a fast H 2 evolution kinetics. This work develops a feasible method for the exploration of H 2 evolution photocatalyst with outstanding charge separation properties. [Display omitted] • Cu and Cu 3 P co-modified TiO 2 nanosheet was fabricated via in situ hydrothermal method. • The Schottky junction and p-n heterojunction work together to enhance the H 2 evolution efficiency. • Low recombination rate of electron-hole pairs is achieved by the dual heterojunction. • The charge transfer pathway was revealed by radical trapping test using TA and NBT as indicator. [ABSTRACT FROM AUTHOR]

The design of p-n heterojunction photocatalysts to overcome the drawbacks of low photocatalytic activity that results from the recombination of charge carriers and narrow photo-response range is promising technique for future energy. Here, we demonstrate the facile hydrothermal synthesis for the preparation of Bi 2 O 3 /MoS 2 p-n heterojunction photocatalysts with tunable loading amount of Bi 2 O 3 (0–15 wt%). The structure, surface morphology, composition and optical properties of heterostructures were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV–visible absorption spectroscopy, Brunauer-Emmett-Teller (BET) surface area, photoluminescence (PL), electrochemical impedance spectroscopy (EIS). Compare to pure Bi 2 O 3 and MoS 2, the Bi 2 O 3 /MoS 2 heterostructures displayed significantly superior performance for photocatalytic hydrogen (H 2) production using visible photo-irradiation. The maximum performance for hydrogen evolution was achieved over Bi 2 O 3 /MoS 2 photocatalyst (10 μmol h−1g−1) with Bi 2 O 3 content of 11 wt%, which was approximately ten times higher than pure Bi 2 O 3 (1.1 μmol h−1g−1) and MoS 2 (1.2 μmol h−1g−1) photocatalyst. The superior performance was attributed to the robust light harvesting ability, enhanced charge carrier separation via gradual charge transferred pathway. Moreover, the increased efficiency of Bi 2 O 3 /MoS 2 heterostructure photocatalyst is discussed through proposed mechanism based on observed performance, band gap and band position calculations, PL and EIS data. • Synthesis of Bi 2 O 3 /MoS 2 p-n heterostructure via hydrothermal method. • The Bi 2 O 3 /MoS 2 photocatalyst showed enhanced H 2 production activity. • The p-n heterostructure promotes the charge transfer and separation. [ABSTRACT FROM AUTHOR]

The novel p-n heterojunction B4C/g-C3N4 photocatalysts were built via ultrasonic dispersion, and solvent evaporation approaches. The properties of the photocatalysts were studied by characterization. The photocatalytic performance of materials was investigated by degradation of Rhodamine B (RhB) and tetracycline (TC). The B4C/g-C3N4 (1/6) showed the best photocatalytic performance for the degradation of RhB (96%, in 70 min). Its degradation rate was 32 % higher than that of single g-C3N4. Besides, 92% TC could be degraded by B4C/g-C3N4 (1/6) in 210 min. Compared with the pure g-C3N4, the photocatalytic activity of the B4C/g-C3N4 composites was improved significantly. On the one hand, the modification of B4C enhanced the light absorption capacity. On the other hand, the formed p-n hetero-junction between B4C and g-C3N4 enhanced the charge transfer rate and inhibited the recombination of photogenerated electrons and holes. Therefore, the composites could generate a lot of active species to degrade aqueous pollutants. In addition, the materials exhibited excellent stability in recycling tests. This study provides novel p-n heterojunction photocatalysts for degradation pollutants. [ABSTRACT FROM AUTHOR]

The threats posed by heavy metal ions and antibiotics present in natural aqueous environments have been a serious cause of concern across the globe. The synchronous elimination of these contaminants through visible light responsive semiconductor mediated photocatalysis is a suitable strategy to solve this problem. However, designing proficient photocatalysts for the said purpose is a crucial task. Herein, hierarchical 3D/2D architectures of Bi 4 O 5 I 2 /g-C 3 N 4 p-n type direct Z -scheme heterojunction photocatalysts (BOCNs) were fabricated by a two-step solvothermal-calcination approach. The characterisation of BOCNs by XRD, FTIR, XPS, SEM, TEM, HRTEM, LSV and MS techniques corroborated the robust heterojunction formation between Bi 4 O 5 I 2 and g-C 3 N 4. The presence of g-C 3 N 4 and application of high treatment temperature (400 °C) assisted the formation of Bi O C bond which is responsible for the development of an intimate interfacial interaction in BOCN. The heterostructured photocatalyst (BOCN3) demonstrated higher rate constant (k Cr(VI)/synchronous) of 0.068 min−1 for Cr(VI) detoxification and that (k TCH/synchronous) of 0.075 min−1 for TCH degradation synchronously with respect to the reported values. The determined rate constants are about 1.8 folds greater than those were observed in isolated systems. The expedited photocatalytic activity can be ascribed to its wide visible light response, minimum charge recombination rate and increased redox ability. These are resulted from the synergistic effect of hierarchical 3D/2D architecture construction, existence of strong Bi O C interfacial bond, p-n heterojunction formation and prevalence of direct Z -scheme charge transfer principle. The synchronous elimination of Cr(VI) and TCH over BOCN3 up to the fifth consecutive cycle without any appreciable change in photoactivity signified its enhanced stability and reusability. The plausible mechanism for the spectacular photocatalytic performance of BOCN3 was proposed. [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel p-n heterojunction composite photocatalyst BaSnO 3 /TiO 2 with anatase/rutile/brookite structure was fabricated. • 5%BaSnO 3 /TiO 2 (Ba/Ti molar ratio=5%) shows higher photocatalytic activity than commercial P25 and pure TiO 2. • A mechanism of improving the photocatalytic performance was proposed based on band potentials analysis and ESR results. • The built-in electric field formed at the p-n heterojunction interfaces promotes the photogenerated charges separation and improves photocatalytic performance. In the present work, new BaSnO 3 /TiO 2 p-n heterojunction composite photocatalysts based on p-type BaSnO 3 and n-type TiO 2 with anatase/rutile/brookite three-phase coexisting were constructed. The microstructure and photocatalytic performance of the prepared composites were investigated. The results show that pure TiO 2 (PT) consists of three phases including anatase, rutile and brookite. Mott-Schottky curves prove that BaSnO 3 and TiO 2 are coupled to form p-n heterojunctions, and the built-in electric field generated at heterogeneous interfaces promotes the separation of photogenerated charges and enhances the photocatalytic performance. When the Ba/Ti molar ratio is 5%, 5%BaSnO 3 /TiO 2 (5%BT) exhibits the highest photocatalytic activity. The first-order reaction rate constant of 5%BT is 0.157 min–1, which is 1.8 and 2.2 times higher than that of commercial P25 (0.089 min–1) and PT (0.071 min–1), respectively. Furthermore, a mechanism of p-n heterojunctions improving the photocatalytic performance is proposed based on band potentials analysis and ESR results. [ABSTRACT FROM AUTHOR]

In heterostructure photocatalysts, interface charge transfer is a crucial step in the photocatalytic process, so it is crucial to construct photocatalysts with high interface charge transfer efficiency. Here we report an in-situ self-assembled flower-like ZnIn 2 S 4 /CdIn 2 S 4 (ZCIS) composites with excellent catalytic performance for atrazine (ATZ) degradation. The ZCIS-4 composite could degrade 99.82% of ATZ within 40 min, which showed 1.42 and 1.91 times better than blank ZnIn 2 S 4 and CdIn 2 S 4 , respectively. The excellent catalytic performance is attributed to the built-in electric field in the in-situ self-assembled composite photocatalyst, which accelerates the rapid transfer of interfacial charges and the rapid separation of photogenerated electron hole pairs. The toxicity assessment shown that some intermediates exhibited decreased toxicities; however, the toxicities were still significant. Active radical capture experiments and electron spin resonance characterization demonstrated that h+, O 2 − were the main active free radicals. Differential charge density simulation calculations verified that interface photogenerated electrons were transported from CIS to the ZIS surface. In-situ self-assembled flower-like ZnIn 2 S 4 /CdIn 2 S 4 photocatalyst with effective photocatalytic performance has been designed for the first time. The composites are competent in photodegradation of Atrazine. The formed p-n heterojunction in the composites accelerates the separation efficiency of photogenerated electron-hole pairs. [Display omitted] • In-situ self-assembled flower-like ZCIS composites were prepared successfully. • The ZCIS-4 composite could degrade 99.82% of ATZ within 40 min. • Photogenerated charge transfer mechanism of composite is a p-n heterojunction type. [ABSTRACT FROM AUTHOR]

[Display omitted] • The novel CoP/CoO/g-C 3 N 4 photocatalyst was successfully developed by loading the co-catalyst CoP onto CoO/g-C 3 N 4 p-n heterojunction by in-situ phosphating. • A highly active CoP/CoO/g-C 3 N 4 photocatalyst was developed using abundant low-cost elements, and the optimized CoP/CoO/g-C 3 N 4 photocatalyst exhibited a better H 2 evolution activity (4036.97 μmol·g−1·h−1) than Pt/g-C 3 N 4. • The charge transfer and intermediate H* adsorption energy were calculated by DFT studies, and the hydrogen evolution mechanism of this photocatalyst was proposed. A prospective and pollution-free approach for producing hydrogen is photocatalytic water-splitting. Designing and developing a catalyst that can separate the photogenerated carriers and offer enough H+ reduction active sites are of paramount importance in boosting the efficiency of photocatalytic H 2 evolution. Herein, the cocatalyst CoP were loaded on CoO/g-C 3 N 4 p-n heterojunction (CoP/CoO/CN, referring g-C 3 N 4 to as CN) by an in-situ phosphating method, and its H 2 evolution activity was measured by simulating sunlight irradiation without adding any noble metal cocatalyst. The CoP/CoO/CN photocatalyst exhibited a better H 2 evolution activity (4036.97 μmol·g−1·h−1) than Pt/CN. The mechanism study demonstrated that the excellent activity is resulted from the formed internal electric field in p-n heterojunction, and the enough active reduction sites from cocatalyst CoP. This work provides a rational design for in-situ loading cocatalysts on heterojunction and is helpful for developing efficient photocatalysts using the abundant low-cost elements. [ABSTRACT FROM AUTHOR]

The rational design and construction of p-n heterojunctions were deemed as an efficient strategy for promoting the separation and migration of photogenerated electron-hole pairs. Here, a facile in-situ deposition process was applied to develop a novel dual-functional Ag 2 O quantum dot/ZnIn 2 S 4 nanosheet (AO/ZIS) composite photocatalyst, which assisted to the uniform distribution of Ag 2 O quantum dots on the surfaces of ZnIn 2 S 4 nanosheets for the fabrication of the unique p-n heterostructure. The as-prepared AO/ZIS hybrids presented significantly enhanced photocatalytic performance for both hydrogen generation and tetracycline hydrochloride (TCH) decomposition. The results indicated that sample AO/ZIS-2 possessed the highest photocatalytic H 2 production capacity (2334.19 μmol·g−1) and TCH photodegradation rate (1.62 × 10−2 min−1), which were 3.38 and 3.82 times as high as those of bare ZnIn 2 S 4. Meanwhile, based on a series of characterization analysis, it could be determined that the increased surface area, enhanced spectral absorption and the fabrication of p-n heterojunction with the interface electric field were primarily responsible for the wonderful photocatalytic activities. Ultimately, the possible energy band transition after contact and photocatalytic mechanism were elucidated according to the ESR and Mott-Schottky results. It is predictable that our work will provide some inspiration for exploring other p-n heterojunctions with excellent performances. Unlabelled Image • The novel Ag 2 O quantum dot/ZnIn 2 S 4 nanocomposite photocatalyst was firstly fabricated. • The formed p-n heterostructure could markedly promote the spatial charge transfer. • AO/ZIS hybrids exhibited superior photocatalytic hydrogen evolution and TCH degradation. • The improved photocatalytic mechanism in composite system was discussed in detail. [ABSTRACT FROM AUTHOR]

Abstract Two dimensional (2D) p–n heterostructures are demonstrated to be promising candidates for future integrated electronics and optoelectronics ascribing to their unique physical, optical and electrical properties. In this work, for the first time, we report the successful synthesis of high quality vertically stacked Sb 2 Te 3 /MoS 2 heterostructures via van der Waals (vdW) epitaxial growth. Due to the p-type nature of Sb 2 Te 3 and n-type nature of MoS 2 , the constructed Sb 2 Te 3 /MoS 2 heterostructure-based devices can function as high performance rectifying diodes, and be further used as photodetectors and photovoltaics. As a result, the achieved p–n heterojunctions exhibit ultra-high current rectification ratio up to 106 and typical photon-to-electron conversion efficiency reaching 4.5%, both of which are much higher than all the previously reported 2D vdW heterojunctions grown by vapor deposition routes. Moreover, remarkable photoresponsivity (330 A/W) and fast photoresponse speed (<500 μs) are achieved, which also represent the highest values reported so far in similar systems. Combing the excellent electrical and optoelectrical properties, the achieved Sb 2 Te 3 /MoS 2 heterostructures may find broad applications in future integrated electronics and optoelectronics devices and systems. Graphical abstract High-quality and large scale vertically stacked Sb 2 Te 3 /MoS 2 heterostructures are achieved with van der Waals epitaxial growth method. Benefiting from the p-type nature of the Sb 2 Te 3 and n-type nature of the MoS 2 , p–n junction is formed at the interface, which shows excellent rectifying behaviors (rectification ratio up to 106) and typical photovoltaic properties (power conversion efficiency up to 4.5%). fx1 Highlights • Vertical Sb 2 Te 3 /MoS 2 p–n heterojunctions are constructed for the first time. • The achieved Sb 2 Te 3 /MoS 2 p–n heterojunctions possess very sharp interfaces. • Efficient charge carriers separation and transfer process were observed. • The p–n diodes exhibit ultra-high current rectification ratio up to 106. • The p–n diodes show excellent photovoltaic properties. [ABSTRACT FROM AUTHOR]

Abstract While searching for an efficient, non-noble, earth-abundant catalyst for the hydrogen evolution reaction (HER), we synthesized hexagonal dinickel phosphide with different nanostructures using solvothermal phosphidation. Coupled atop p- type Si, this catalyst performed as a p-n heterojunction photocathode assembly and the performance varied when under different electrolyte media. Apart from changing the surface morphology, Ni 2 P was crystallized with an increase in the Niδ+/Ni2+ ratio as the phosphidation temperature gradually increased. A systematic evaluation of the water splitting reaction shows that a very small amount of catalyst (>85% transmittance for the catalyst layer) exhibits a photocurrent of −10 mA cm−2 with a positive applied potential of 0.05 V versus reversible hydrogen electrode under simulated solar irradiation of AM 1.5G. We discuss the substantial charge transfer process at the depletion layer of the electrode/catalyst and the catalyst/electrolyte interface. Mott–Shottky analysis showed a shift in the flat band potential for Ni 2 P, which reveals the underlying mechanism for the role of the p-n junction for enhanced photoelectrochemical cell performance. Highlights • The Hexagonal phase Ni 2 P is changing Niδ+/Ni2+ ratio with phosphidation temperature. • p- Si coupled with as-prepared Ni 2 P performed as p-n heterojunction photocathode unit. • Optimized photocurrent obtained with 10 mA cm−2 at positive applied potential of 0.05 V. • Shifting of flat-band potential validated the charge transfer process. [ABSTRACT FROM AUTHOR]

Abstract Constructing junctions between semiconductors is an effective way to promote charge separation and thus to improve the photoelectrochemical (PEC) performances, and specifically, p-n heterojunction is considered as a very promising structure. Herein, we designed and fabricated MoS 2 /nitrogen doped graphene hydrogels (MoS 2 /NGH) p-n heterojunction by a facile one-pot hydrothermal route. The as-fabricaterd MoS 2 /NGH heterostructures demonstrated the excellent PEC activity, exhibiting enhanced photocurrent intensity by the fast transfer and separation rate of photogenerated electron-hole owing to the construction of p-n heterojunction. Based on the high PEC performances of the MoS 2 /NGH heterostructure, a novel sensitive PEC sensor was developed for the determination of chloramphenicol (CAP) with the assistance of aptamer. In the presence of target molecules, the as-fabricated PEC sensor could recognize the CAP quickly and then consume the holes in the interface of heterostructures, inhibiting the recombination of photogenerated electron-hole pairs, resulting the enhanced photocurrent. Specially, with the concentration of CAP increased, the photocurrent enhanced gradually. Excellent linearity was obtained in the concentration range from 32.3 ng/L to 96.9 μg/L, and the limit of detection was 3.23 ng/L. Moreover, the as-fabricated PEC sensor exhibited rapid response, high stability, low-cost and high selectivity, which could be successfully applied to the analysis of CAP in honeycomb samples. Highlights • MoS 2 /NGH p-n heterojunctions were prepared by the one-pot hydrothermal route. • Such p-n heterojunction were beneficial to facilitate the charge transfer. • A simple and novel PEC aptasensor for CAP assay was developed based on MoS 2 /NGH. • This sensor exhibited high sensitivity, low detection limit, wide linear range, and etc. • The sensor was successfully applied to the analysis of CAP in honeycomb. [ABSTRACT FROM AUTHOR]

[Display omitted] • ZIF-67-derived hollow CsPbBr 3 /Co 3 O 4 was prepared by microwave-assisted method. • Efficient photoconversion of CO 2 was achieved upon the CsPbBr 3 /Co 3 O 4 photocatalyst. • Oxygen vacancies and enhanced built-in electric fields existed in p-n junction. • Formed Cs-O bonds acted as the charge transfer channels at the interface. Surface defect or p-n heterojunction is considered as an efficient strategy to fabricate intrinsic built-in electric field and facilitate the charge separation and transfer. Herein, a novel p-n heterojunction photocatalyst CsPbBr 3 /Co 3 O 4 was constructed by a facile microwave-assisted method, in which CsPbBr 3 QDs anchored on ZIF-67 derived Co 3 O 4 nanocage can simultaneously introduce oxygen vacancies and strengthen the interfacial interaction. As a result, the as-prepared CsPbBr 3 /Co 3 O 4 displays the satisfactory photocatalytic CO 2 reduction performance without photosensitizer and sacrificial agent, and the optimal catalyst exhibits that the average electron consumption rate (R electron) is 158.80 μmol‧g−1‧h−1, which is 12.41 times higher than that of pure CsPbBr 3. Photoassisted Kelvin probe force microscopy (KPFM) and experimental characterizations exhibit the formation of strong built-in electric fields probably due to the rich oxygen vacancies in this p-n heterojunction. Besides, DFT calculations confirm that the charge transfer pathway, where the electrons are quickly migrated to the catalytic active sites through the formed Cs-O bonds, thus accelerating the charge separation. This work could establish an effective strategy for the rational design of p-n heterojunction to achieve high-performance CO 2 conversion. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cu-BTC@CuS@CeO 2 double p-n heterojunction hollow octahedrons were fabricated. • Cu-BTC@CeO 2 and hollow structure were concurrently realized by one-step process. • The catalyst exhibited high visible light absorption and multipath fast charge transfer. • The catalyst provided a remarkable Vis/NIR light oxidation activity of amines to imines. Hollow heterostructured catalysts have been widely investigated and applied in photocatalytic organic reactions. However, achieving hybrid catalysts with optimized hollow structure and controllable components is still a challenge. Herein, Cu-BTC@CuS@CeO 2 ternary heterostructure hollow octahedrons were designed and prepared using a copper-based metal–organic framework (Cu-BTC) as both copper source and template. A thin CeO 2 nanolayer was first formed and covered on the prepared Cu-BTC octahedron surface through a hydrothermal process. In the meanwhile, the Cu-BTC octahedrons were controllably etched in this hydrothermal process, leading to the formation of Cu-BTC@CeO 2 hollow octahedron. The following sulfidation reaction produced Cu-BTC@CuS@CeO 2 double p-n heterojunction hollow octahedrons. Benefiting from the novel hollow octahedron double p-n heterojunctions, excellent visible-near infrared light absorption, and fast charge transfer and separation, the obtained Cu-BTC@CuS@CeO 2 hollow octahedron hybrid catalyst exhibited a significantly higher photocatalytic activity toward the oxidative coupling of amines to imines at room temperature under visible-near infrared light irradiation compared to the control single component catalysts (Cu-BTC, CeO 2 , and CuS) and binary hybrid catalysts (Cu-BTC@CeO 2 , Cu-BTC@CuS, and CuS@CeO 2). The enhanced charge transfer at the double p-n heterojunction was discussed. Meanwhile, the photocatalytic oxidation products and reaction mechanism were investigated by surface-enhanced Raman spectroscopy, gas chromatography-mass spectrometry, and pyridine adsorption FT-IR spectroscopy. This work presents a promising strategy for the design of multi-component hollow heterostructure catalysts. [ABSTRACT FROM AUTHOR]

The photocatalytic hydrogen production is one of the clean and renewable methods of converting solar energy to chemical fuels. Herein, an 0D/1D Cu 2 NiSnS 4 /TiO 2 (B) p-n heterojunction photocatalyst was prepared by a hydrothermal route. The FE-SEM, and HR-TEM analysis revealed that the 1D nanowire morphology of TiO 2 (B) was coated uniformly with Cu 2 NiSnS 4 (CNTS) nanoparticles. With an average particle size of 5 nm, CNTS nanoparticles improved the interfacial contact and formed an efficient p-n heterojunction with TiO 2 (B), which greatly improved the charge carrier separation, as evident from the transient photocurrent, photoluminescence, and impedance spectroscopies. The optimized Cu 2 NiSnS 4 /TiO 2 (B) sample produced an average of 7144 µmol/g of hydrogen in 4 h of reaction time under direct sunlight irradiation, which is nearly five times higher than bare TiO 2 (B). Based on the Mott-Schottky and UV–visDRS spectra, a Z-scheme p-n junction charge transfer mechanism has been proposed. [Display omitted] • A 0D/1D Cu 2 NiSnS 4 /TiO 2 (B) photocatalyst was prepared by a hydrothermal route. • The 1D TiO 2 (B) nanowires are coated uniformly with Cu 2 NiSnS 4 nanoparticles. • The 5 nm size Cu 2 NiSnS 4 nanoparticles formed an interfacial contact and efficient p-n heterojunction with TiO 2 (B). • The Cu 2 NiSnS 4 /TiO 2 (B) produced an average of 7144 µmol/g of hydrogen in 4 h. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel 0D/2D dot-on-plate AgFeO 2 -Bi 4 TaO 8 Cl p-n heterojunction was constructed. • AgFeO 2 -Bi 4 TaO 8 Cl exhibits superior photocatalytic degradation activity towards ofloxacin antibiotic. • Facet-assisted charge separation was identified for n-type Bi 4 TaO 8 Cl. • The p-n heterojunction enhances light absorption and spatial charge separation. • The main reactive species for the photocatalytic mechanism were discussed. Accelerating charge transfer is believed to be a feasible strategy to improve the photocatalytic performance of heterojunctions. Herein, a novel dot-on-plate heterojunction was designed and constructed by anchoring p-type AgFeO 2 nanoparticles on the surface of n-type Bi 4 TaO 8 Cl nanosheets via a facile ultrasound-assisted deposition combined with calcination process, which endows an intimate p-n heterointerface. The Bi 4 TaO 8 Cl nanosheets with mainly exposed {0 0 1} and {1 1 0} facets show unique facet-assisted charge carrier separation. After building up the p-n heterojunction, the established internal electric field further promotes the separation and migration of photogenerated charge carriers, and hinders the charge carrier backflow for recombination at the heterointerface. As a result, compared to pure AgFeO 2 and Bi 4 TaO 8 Cl, AgFeO 2 -Bi 4 TaO 8 Cl p-n heterojunction exhibits greatly enhanced activity in the photocatalytic degradation of ofloxacin (OFL) antibiotic under visible light irradiation. This work could provide meaningful insights into the design of efficient p-n heterojunction for steering interfacial charge flow and applying in photocatalytic environmental remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • g-C 3 N 4 nanotubes have large specific surface area and more active sites. • p-n heterojunction interface generates electric field, accelerates electron and hole transfer, and inhibits carrier recombination. • The hollow hierarchical heterogeneous structure shortens the carrier migration path, which is conducive to charge separation and transfer. Graphite carbon nitride (g-C 3 N 4) is considered as a promising photocatalyst for CO 2 reduction. However, they have problems such as small surface area and fast electron hole recombination rate, so how to improve the photocatalytic efficiency of g-C 3 N 4 remains a great challenge. In this paper, g-C 3 N 4 /MnFe 2 O 4 p-n heterojunction composites were synthesized successfully, and their photocatalytic activity for CO 2 reduction was tested. We constructed g-C 3 N 4 nanotubes to increase its specific surface area and increase the active sites available for reaction. The structure of p-n heterojunction promotes electron hole separation. The results indicate that under visible light irradiation, CO yield of g-C 3 N 4 /MnFe 2 O 4 composite can reach 1136.8 μmol h−1 g−1 when the molar ratio of g-C 3 N 4 microtubules to MnFe 2 O 4 is 10:3, which is 14 times of g-C 3 N 4 microtubules and 29 times of g-C 3 N 4. This study provides some guidance for the design of g-C 3 N 4 based heterojunction. [ABSTRACT FROM AUTHOR]

Inorganic lead halide perovskites have attracted wide attention in photovoltaic and photocatalytic applications due to their high photoelectric conversion efficiency. However, improving the stability and charge transfer efficiency of perovskites remains a significant challenge, especially in polarity solvent-based photocatalytic applications. Here, we successfully grew CsPb 2 Br 5 particles on g-C 3 N 4 to construct p-n heterojunctions in an aqueous solution. The prepared CsPb 2 Br 5 /g-C 3 N 4 p-n heterojunctions exhibited enhanced photoelectrochemical and photocatalytic performance, as well as better environmental stability in polar solvents (such as water). This enhancement is considered that p-n heterojunctions can effectively promote the separation and transfer of photogenerated carriers and no ligands that hinder the charge transfer are used. The successful synthesis of ligand-free CsPb 2 Br 5 /g-C 3 N 4 p-n heterojunction extends the application of perovskite materials in the fields of photoelectrochemistry and photocatalysis. [Display omitted] • Ligand-free CsPb 2 Br 5 /g-C 3 N 4 p-n heterojunction was synthesized in aqueous solution. • The CsPb 2 Br 5 /g-C 3 N 4 exhibits superior photocatalytic activity and enhanced photoelectrochemical performance. • The p-n heterojunctions exhibited better environmental stability in polar solvents (such as water). [ABSTRACT FROM AUTHOR]

Towards the photoelectrocatalytic degradation of ciprofloxacin, BFO/BVO heterojunction was constructed to improve the performance of the individual semiconductors. The enhanced performance of the heterojunction photoanode was attributed to increase in visible light harvesting, greater current mobility leading to higher current density, low charge transfer resistance, and low recombination rate of photogenerated electron and hole. The BFO, BVO and BFO/BVO photoanodes prepared were immobilized on fluorine doped tin oxide coated glass and characterised using x-ray diffractometry, scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy (EIS), UV–vis diffusive reflectance spectroscopy, photocurrent measurement, ultra performance liquid chromatography- mass spectrometry (UPLC-MS). The percentage removal of ciprofloxacin using BFO, BVO and BFO/BVO photoanodes were 56%, 49% and 80.3% respectively. The current density of the heterojunction photoanode were markedly improved when compared to the individual performances of the photoanodes. Also, the BFO/BVO heterojunction photoanode showed stability after repeated usages. Data from UPLC-MS studies was used to propose the degradation pathway, products, and mechanism of the degradation process.. [ABSTRACT FROM AUTHOR]

[Display omitted] • Formation ways, types and effect mechanisms of p-n heterojunction are analyzed. • Charge transfer mode under the effect of electric field and band structure is studied. • Application of p-n heterojunction in environmental remediation is discussed. • Challenges and perspectives facing p-n heterojunction are proposed. Photocatalysis, a promising green technique, is drawing increasing attention in the field related to environmental protection, due to the advantages of low energy consumption, no pollution and easy operation. However, easy recombination of photogenerated electrons and holes makes apparent quantum yield low, which is a major limiting factor for the practical application of photocatalysis. Lately, a growing body of research shows that construction of p-n heterojunction may be an effective strategy to improve the photocatalytic performance. Normally, owing to the differences in Fermi levels and work functions between p-type and n -type semiconductors, the formation of p-n heterojunction can create an internal electric field, which will provide electrostatic force for regulating the charge transfer. In this review, the formation ways, combination types and effect mechanisms of p-n heterojunction based on staggered gap are summarized, and the charge transfer modes under the joint effects of built-in electric field and band structure are analyzed and discussed with emphasis. Meanwhile, the applications of p-n heterojunction in environment domain are also briefly summarized, including pollutant removal, sterilization, water splitting and CO 2 reduction. The challenges and prospects for p-n heterojunction are also proposed. To sum up, current review may offer a valuable reference for designing and constructing p-n heterojunction in future work. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bi 2 S 3 /MnOS was fabricated by a one-step hydrothermal approach. • Ag phot deposited on the surface for efficient nitrogen fixation. • Heterojunction is helpful for the adsorption and activation of nitrogen to ammonia. • High photocatalytic nitrogen fixation yield was achieved. • A systematic study of the photocatalytic mechanism was proposed. Photocatalytic nitrogen reduction reaction (PNRR) is clean and sustainable, considered an ideal synthesis technology for ammonia (NH 3). In this study, we in situ developed the n-Bi 2 S 3 nanorod/p-MnOS cubic composite catalyst for the first time using a one-step hydrothermal method, as MnOS, listed in the X-ray diffraction standard data file as an uncharacterized compound, has not been reported since 1965. Then, using a photodeposition technique, Ag nanoparticles (NPs) were added to the surface of the Bi 2 S 3 /MnOS to enhance PNRR via the surface plasmon resonance. After different characterization techniques for evaluation, Ag-Bi 2 S 3 /MnOS is found to be highly effective in the spatial separation of photogenerated electron-hole pairs due to the charge transfer at the composite interface. Photodeposited Ag is applied as an electron trapper to enhance the spatial separation of charge carriers. Based on their ability to reduce nitrogen under simulated solar light irradiation, the PNRR activities of Bi 2 S 3 , MnOS, Bi 2 S 3 /MnOS, and 0.5 to 2 % Ag-Bi 2 S 3 /MnOS were evaluated. After two hours, the PNRR activity of 1 % Ag-Bi 2 S 3 /MnOS produced ammonia 5.9 mmol/g, double the amount of Bi 2 S 3 /MnOS composite and approximately 5 times the amounts of Bi 2 S 3 and MnOS materials. PNRR enhancement involves the internal static electron field created at the n -type Bi 2 S 3 /p-type MnOS interface and the improved electron conductivity with the photodeposition of Ag NPs, to speed up the reaction of reactive species. The importance of solid solution engineering in material design is demonstrated in this work. [ABSTRACT FROM AUTHOR]

The design and synthesis of visible light-responsive heterogeneous catalysts for the effective removal of contaminants are critical areas of research in the environmental catalysis. In this study, DyFeO 3 /g-C 3 N 4 p-n heterojunctions (DFCs) were successfully synthesized. TEM, HRTEM, SEM, FTIR and XPS results clarified the successful formation of DFCs and their ultra-thin and porous structure. DRS and XPS VB spectra revealed that the DFCs were type Ⅱ heterojunctions with strong visible light absorption. TPC, EIS, PL and PL decay spectra confirmed the increase of the separation efficiency and the inhibition of the recombination of the photogenerated charge carriers in DFCs. DFC-2 (containing 2 wt% of DyFeO 3) exhibited the best photo-Fenton degradation performance. The highest degradation efficiency was 99.1%, 100%, and 99.6% on DFC-2 for oxytetracycline, methylene blue, and rhodamine B, respectively. The photo-Fenton antibacterial efficiency was over 99% after 15 min of visible light irradiation. Moreover, the antibacterial effect was 4 times and 2.7 times that of photocatalytic or Fenton antibacterial processes. The internal electric field generated at the interface between DyFeO 3 and g-C 3 N 4 ameliorated the spatial separation and transfer features of charge carriers. In addition, the accelerated transfer of the electrons facilitated the reduction of Fe3+ to regenerate Fe2+, which further enhanced the photo-Fenton degradation and antibacterial activity. In a radical scavenger experiment, ESR and HPLC-MS were employed to identify the major active species and intermediates in the photo-Fenton degradation of oxytetracycline. The degradation pathways and mechanism were reasonably inferred. This study proposes promising DFCs with p-n heterostructures for the effective photo-Fenton removal of oxytetracycline and antibacterial activity. • A novel ultrathin DyFeO 3 /g-C 3 N 4 p-n heterojunction was manufactured. • The photo-Fenton degradation and antibacterial activity were efficiently promoted. • The internal electric field ameliorated the spatial separation of charge carriers. • The photo-Fenton antibacterial efficiency was over 99%. [ABSTRACT FROM AUTHOR]

Bi-based semiconductors have been regarded to be an ideal platform in photocatalytic CO 2 reduction to fuels. However, the insufficient charge transfer efficiency greatly restricts their practical application. Herein, we fabricated 1D/2D hierarchical heterostructures by the hybridization of Bi 4 O 5 Br 2 and rod-like MOF-derived MoS 2 anchored in nitrogen-doped porous carbon (NPC-MoS 2) using Mo-MOF as a precursor followed by sulfidation and typical solvothermal process. Compared to pristine Bi 4 O 5 Br 2 nanosheet and NPC-MoS 2 nanorod, the 5 wt% NPC-MoS 2 @Bi 4 O 5 Br 2 p-n heterojunction exhibits distinctly enhanced photocatalytic activity under light illumination due to the increased light absorption capability and more effective charge transfer efficiency. X-ray photoelectron spectroscopy and photoelectrochemical analysis imply that a built-in electric field on interfaces is created to form p-n heterojunctions which drive the photoinduced electrons transferred from NPC-MoS 2 to Bi 4 O 5 Br 2. Finally, the type-II charge transfer mechanism is proposed which promotes separation of the charges and provides suitable conduction band to reduce CO 2 much efficiently. In a word, this work provides a new insight into the establishment of hierarchical p-n heterostructures for photocatalysis. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A newly-designed double p-n heterojunction based on ternary composite was prepared. • Rational growth of NiO and MIL-101 on g-C 3 N 4 surface enhanced its optical absorption. • Formation of build-in electric field accelerated the transfer of photoinduced carrier. • Ternary composite had a good photocatalytic performance in environmental remediation. • Possible photocatalytic mechanism and transfer path of charge carrier were proposed. In this study, a double p-n heterojunction based on g-C 3 N 4 @NiO/Ni@MIL-101 ternary composite was successfully prepared by a feasible method. Results suggested that the rational growth of NiO and MIL-101 on the surface of g-C 3 N 4 can improve the absorption capacity for visible light. Importantly, the formation of double p-n heterojunction can effectively inhibit the recombination of photogenerated electrons and holes. Due to the significant Fermi level differences among NiO, MIL-101 and g-C 3 N 4 , the internal electric fields were established on the interface after constructing the composite, consequently reducing the electrical resistance and accelerating the transfer of photoinduced charge carriers. As expected, the g-C 3 N 4 @NiO/Ni@MIL-101 ternary composite with good stability had excellent photocatalytic performance in the degradation of emerging pollutants, and the removal efficiency of ibuprofen was as high as 95.6%. The •O 2 −, •OH and 1O 2 were the major active species in the reaction system. Furthermore, developed photocatalytic oxidation system can also achieve the rapid inactivation of bacteria. Based on the synergistic effects of energy band position and double internal electric fields, the separation and transfer of photogenerated charge carriers followed a traditional type-II route. In short, current work not only constructed a promising photocatalyst, but also shared an effective strategy for boosting the photocatalytic activity. [ABSTRACT FROM AUTHOR]

A novel p-n heterostructure Ag-Ag 2 MoO 4 /polyaniline (Ag-Ag 2 MoO 4 /PANI) composite was synthesized via a facile oxidation polymerization followed by co-precipitation. The surface morphology, structure, optical and photoelectrochemical properties of the as-prepared composites were determined using various techniques, and the photocatalytic activity was evaluated using chromium (VI) [Cr(VI)] and methyl orange (MO) as target inorganic and organic pollutants under visible-light irradiation. The results showed that the p-n heterostructure was formed between Ag-Ag 2 MoO 4 and PANI, which could effectively promote the rapid transfer and separation of the photogenerated electron-hole pairs. At the same time, the metallic Ag nanoparticles on the surface harvested visible-light photons and generated extra plasmonic hot electrons to enhance the photocatalytic activity. As expected, the optimal Ag-Ag 2 MoO 4 /PANI 0.10 exhibited high photocatalytic activity in the Cr(VI) reduction and MO degradation owing to the fast separation and transfer of the electron-hole pairs. Moreover, trapping experiment revealed that •OH and •O 2 − played a vital role during the MO degradation process. Based on various characterizations and experimental results, the possible photocatalytic mechanisms were proposed. This work gave a simple method to construct p-n heterostructure photocatalysts for environmental restoration. • p-n heterostructure Ag-Ag 2 MoO 4 /PANI composite was successfully synthesized via a PANI precursor route. • The composite presented excellent activity for Cr(VI) reduction and organic pollutant degradation under visible-light. • The synergy of the LSPR effect and the p-n heterostructure promoted charge separation and transfer. • PANI and metallic Ag enhanced light harvesting and boosted active species generation. [ABSTRACT FROM AUTHOR]

Green bismuth-based photocatalysts have attracted extensive attention in the field of PPCPs photodegradation. The improved carrier separation efficiency still remains a key factor to enhance photocatalytic performance. Herein, N-doped biomass carbon quantum dots (N-CQDs) decorated p-n heterojunction photocatalyst BiO 2−x /BiOCl was prepared using a facile ion-etching strategy, and it displayed a markedly enhanced catalytic activity in the photodegradation of sulfonamide antibiotics. Calculated by the differential charge density, the doped N-CQDs could gather photogenerated electrons, which indicated that the introduction of N-CQDs into BiO 2−x /BiOCl would effectively inhibit the recombination of photogenerated charge carriers. In addition, photocatalytic performance and density functional theory (DFT) calculation results revealed that the photogenerated electrons tended to transfer from p-BiOCl to n-BiO 2−x through N-CQDs, which could generate ·O 2 - and photogenerated h+ to oxidize the target pollutants. Benefiting from the synergistic effect of accelerated separation of e--h+ in p-n heterojunction and the electron-rich performance of N-CQDs, the superb TOC removal efficiencies (89.40% within 120 min visible-light irradiation) and toxicity reduction performance of photodegradation intermediates were achieved. As a consequence, this work will provide a design of high-quality photocatalysts and a green-promising strategy for bismuth-based photocatalysts in the water treatment of PPCPs. [Display omitted] • N-CQDs/BiO 2−x /BiOCl (BBN) photocatalyst was prepared by ion-etching methods. • The doped N-CQDs act as an electron acceptor to effectively suppress the recombination of e--h+. • DFT calculation was used to study the charge transfer mechanisms. • The synergistic effect of p-n heterojunction and N-CQDs promoted the SMX photodegradation. [ABSTRACT FROM AUTHOR]

CoFe 2 O 4 /g-C 3 N 4 p-n heterojunction photocatalysts have been successfully synthesized. The formation of p-n heterojunction and the unique morphology of g-C 3 N 4 enhanced electron transfer and charge separation, leading to a significant improvement in photocatalytic efficiency. 5-CoFe 2 O 4 /CNS not only had a high photocatalytic hydrogen evolution rate of 18.9 mmol·g−1·h−1, but also possessed an efficient photocatalytic fluoroquinolone antibiotics removal efficiency. A smaller band gap in 5-CoFe 2 O 4 /CNS photocatalyst promoted more light generated electrons under visible light irradiation. An internal electric field at the contact interface accelerated the accumulation of electrons and holes in the valence band of g-C 3 N 4 and conduction band of CoFe 2 O 4 , thereby revealing a higher separation efficiency and noticeable inhibited recombination rate of the photoinduced electrons and holes. Also, improved removal efficiency for fluoroquinolone antibiotics was attained in the self-designed acousto-optic microreactor, which was 7.2 and 30 times higher than quartz glass tube and batch experiment, respectively. [Display omitted] • The formation of p-n heterojunction with internal electric field showed an activity superior to individual constituents. • Photocatalytic activity of CoFe 2 O 4 /g-C 3 N 4 p-n heterojunctions was affected by composition ratio and morphologies. • The formation of p-n heterojunctions was associated with the morphology of g-C 3 N 4. • 5-CoFe 2 O 4 /CNS possessed a larger specific surface area, more photo-generated electrons, excellent separation efficiency • A novel acousto-optic microreactor further improved the removal efficiency with 30-fold higher than the batch experiment. [ABSTRACT FROM AUTHOR]

• Cu 3 Mo 2 O 9 /TiO 2 composite was prepared by a simple physical mixing method. • Cu 3 Mo 2 O 9 was first employed in photocatalytic hydrogen evolution from water splitting. • H 2 production rate of 10 wt. % Cu 3 Mo 2 O 9 /TiO 2 is 14.5 times higher than that of TiO 2. • The charge transfer between Cu 3 Mo 2 O 9 and TiO 2 follows the Type-Ⅱ route. The heterojunction formed by semiconductors with a matching electronic energy level structure can effectively promote charge transfer, thereby greatly improving the photocatalytic hydrogen production activity of the catalyst. Herein, the Cu 3 Mo 2 O 9 /TiO 2 hybrid was prepared via a simple mechanical mixing method. In the binary composite, the p-n heterojunction formed between Cu 3 Mo 2 O 9 and TiO 2 can favor the charge separation, resulting in excellent hydrogen production rate of 3401.9 μmol·g−1·h−1, it is 14.5-fold of pristine TiO 2. According to the optional and photoelectrochemical properties, it can be confirmed that Cu 3 Mo 2 O 9 plays a pivotal role in accelerating charge transfer and improving light absorption capacity of the composite. As a new type of photocatalyst, there is very limited information on Cu 3 Mo 2 O 9 for its application in photocatalytic hydrogen production. This work provides the possibility to expand application range of Cu 3 Mo 2 O 9 in energy conversion. [ABSTRACT FROM AUTHOR]

A 3D hierarchical nanocages photocatalyst CuS@ZnIn 2 S 4 with abundant and compact nanosheets 2D/2D hetero-interfaces showed an improved visible light photocatalytic performance for H 2 production in the absence of any cocatalyst. [Display omitted] • This is the first report of the use of CuS nanosheets to assemble 3D nanocages. • The CuS@ZnIn 2 S 4 nanocages have compact nanosheets 2D/2D hetero-interfaces. • The nanocages photocatalyst displayed an improved hydrogen evolution rate. • The 2D/2D hetero-interfaces is favorable for carrier separation and transfer. Photocatalysis based on metal sulfide semiconductor is considered as an economic, safe, renewable, and clean technology. However, the availability of photocatalysts is limited by the low solar energy utilization efficiency and the fast recombination of photogenerated electron-hole pairs. Developing a hollow heterostructure photocatalyst based on semiconductors for enhancing solar energy utilization and separation efficiency of photogenerated carriers is crucial in the photocatalytic H 2 production reaction. The as-prepared 3D hierarchical nanocages photocatalyst CuS@ZnIn 2 S 4 with abundant and compact nanosheets 2D/2D hetero-interfaces displayed an improved photocatalytic hydrogen evolution rate as high as 7910 μmol h−1 g−1 in the absence of any cocatalyst. This is the first report of the use of CuS nanosheets-assembled hollow cubic cages to construct 3D hierarchical nanocages photocatalysts. The close distance between the two nanosheet subunits induce the strong interaction, which was advantage to the separation and transfer of charge carriers. In addition, the hollow structure can not only enhance light adsorption, but also suppress photogenerated carrier recombination. The experimental characterizations and theory calculations confirmed that the strong interaction between CuS and ZnIn 2 S 4 2D/2D hetero-interfaces can extremely facilitate the separation of photogenerated charge carriers and accelerate the electrons transfer. The present work provides a feasible method to construct heterojunction photocatalyst for hydrogen evolution via water splitting powered. [ABSTRACT FROM AUTHOR]