Photogenerated Electron-hole Pairs Research Articles

High-performance GaN ultraviolet polarization-sensitive photodetector based on ferroelectric polarization LiNbO3

High responsivity ultraviolet (UV) photodetectors (PDs) are essential for abundant civilian and military applications. Gallium nitride (GaN) has emerged as an ideal material for UV PD fabrication due to its favorable properties. However, the quality of GaN epitaxial layers significantly impacts device performance and reliability. Sapphire-based GaN epitaxial growth technology enables the realization of high-quality GaN epitaxial layers, making it the preferred choice for GaN substrates. Nonetheless, the thermal expansion coefficient mismatch between sapphire and GaN can lead to crystal mismatch and stress accumulation at high temperatures, affecting device performance and reliability. In contrast, lithium niobate (LiNbO3) exhibits similar coefficients of thermal expansion to GaN, mitigating crystal mismatch and stress accumulation issues. Here, we report the realization of a GaN UV PD by laminating GaN membrane onto ferroelectric LiNbO3 through selective electrochemical etching of the sapphire-based GaN epitaxial film. The LiNbO3-based GaN PD achieves a specific high on/off ratio of 107. At a 5 V bias voltage, the device exhibits a high peak responsivity of 1.712 × 103 A/W under 325 nm laser illumination. Furthermore, the device demonstrates excellent performance for polarization light detection, with a polarization ratio of approximately 54.95. Exploiting the local ferroelectric polarization of x-cut LiNbO3, the photogenerated electron–hole pairs in GaN are efficiently separated by the electrostatic field from the polarization of ferroelectric LiNbO3, resulting in enhanced light-to-electric conversion efficiency. Our work presents a method for fabricating high responsivity GaN-based UV PD, showcasing the potential of integrating ferroelectric LiNbO3 to enhance device performance.

Spinous Au@Ag Bimetallic Nanowires: Synthesis and In Situ Monitoring SERS of Plasmonic Catalysis.

In situ monitoring of reactant transformations at metal catalyst surfaces and/or interfaces, combined with the identification of intermediate species and products, is vital for elucidating catalytic processes and behaviors. We developed innovative spinous Au@Ag nanowires (NWs) with a bimetallic structure and dense alloy protrusions, demonstrating both catalytic activity and surface-enhanced Raman spectroscopy (SERS) capabilities, thereby facilitating in situ SERS tracking of reactions. The spinous Au@Ag NWs exhibit sharp spikes on their surface, providing a large number of catalytically active sites. They demonstrate outstanding sensitivity, signal reproducibility, and homogeneity when detecting representative dye molecules like crystal violet. Furthermore, the spinous Au@Ag NWs exhibit outstanding catalytic performance, enhancing the separation and movement of photogenerated electron-hole pairs. This research offers important insights for the design of multifunctional SERS substrates and paves the way for new opportunities in the in situ monitoring of catalytic processes.

Reduction of the photogenerated electron transport path by modulating the conduction band region to achieve the highest lignin β–O–4 bond photocleavage efficiency under xenon excitation

Photocracking of lignin β–O–4 bonds is a green approach for the high-value modification of lignin. Graphitic carbon nitride (g-C3N4) that can photocleave the β–O–4 bond is presently the only stable, metal-free photocatalyst owing to the residual metal ions generated due to photocorrosion of metal sulfides. Herein, g-C3N4 with a N–C3 vacancy structure is prepared by etching site–engineering strategy based on the protection of C–N=C structure by chlorine atom. The N–C3 vacancy structure can reduce the transport path of the photogenerated electrons by tuning the conduction band (CB) region to the edge of the photocatalyst, which impedes the critical complexation of the photogenerated electron–hole pairs and enhances the photoelectric conversion efficiency five-fold. Combined with the unique chemisorption capacity (137.82 kJ/mol) of N–C3 vacancies for oxygen, the g-C3N4 photocatalysts with N–C3 vacancy structure can generate 9.6-fold higher superoxide radicals and 13-fold higher lignin β–O–4 bond photocleavage efficiency lignin compared with untreated g-C3N4. Based on the reaction enthalpy changes and free energies investigated through simulations, a route of lignin Cα–Cβ bonds being oxidized and dehydrogenated twice by photogenerated cavities is proposed for the first time. This work reveals the relation between the properties of g-C3N4 and the photocleavage efficiency of lignin β–O–4 bonds.

Synthesis of H2O2 to Self-Catalyzed Generation of •OH over ZnO/CuI/Cu Foam Electrode for the Self-Fenton Cleaning of Wastewater.

A novel ZnO/CuI/Cu foam electrode was constructed, which demonstrated excellent photoelectrocatalytic activity for the self-Fenton degradation of tetracycline in water. The H2O2 yield was 405.0 μmol L-1 over ZnO/CuI/Cu foam (CIZ-3) under light irradiation (100 mW cm-2) for 5 h at -1.23 V (vs NHE), which was 1.7 times higher than that of ZnO/Cu foam and 1.6 times higher than that of CuI/Cu foam, respectively. The 99.0% of tetracycline was degraded by CIZ-3 due to its efficient yield of H2O2 to self-catalyzed generation of •OH. The results of the open-circuit potential between CuI and ZnO displayed that the electrons from the conduction band of CuI flowed to ZnO and the holes from the valence band of ZnO migrated to CuI. As a result, the photogenerated electron-hole pairs of ZnO/CuI were efficiently separated, which greatly promoted the photoelectrocatalytic activity of ZnO/CuI/foam. The toxicity of the aqueous tetracycline solution was significantly reduced by observing the growth of Escherichia coli in the treated wastewater.

Efficient photocatalytic decomposition of NO and mechanism insight enabled by NaBH4-reduced N(ligancy-3)-vacancy-rich-graphitic carbon nitride

Vacancy defect engineering is an effective means to improve the performance of g-C3N4 photooxidation for NO removal. In this paper, flake graphite-phase g-C3N4 is prepared by thermal polycondensation. Then g-C3N4-x (x = 0, 0.5, 1.0, 1.5, and 2.0) containing various amounts of vacancies of nitrogen atoms with (3 coordination number) ligancy 3 (N(ligancy-3)) was prepared by NaBH4 reduction at room temperature. The introduction of N vacancies in g-C3N4 narrowed the forbidden gap, enhanced optical absorbance, optimized photo exciton separation and migration, and functioned as traps to mitigate the recombination of photogenerated electron-hole pairs. As a result, g-C3N4-x shows a superior NO removal performance, especially g-C3N4-1.5, which exhibits a high NO removal rate of 66.7%, excellent resistance to the by-product NO2, and excellent stability. The free-radical seizure experiments and electron paramagnetic resonance (EPR) studies proved the superiority of superoxide radicals, electrons and holes as the prominent free radicals in the photocatalytic NO removal process. In situ diffuse infrared Fourier transform spectroscopy (DRIFTS) confirmed that the cis-dimer (NO)2 produced from NO adsorption on the surface of g-C3N4-1.5 is an important intermediate. Additionally, NO2- is observed as an intermediate and a primary product, and NO3- is identified as the key product of NO photocatalytic oxidation. DFT calculations showed that the N(ligancy-3) vacancy introduces impurity energy levels in g-C3N4 and shortens the electron migration path. The adsorption calculation of NO demonstrated that g-C3N4-N(ligancy-3) exhibits good adsorption and conversion of NO. This study provides a practical defect engineering for the g-C3N4 to remediate environmental pollution.

Oxygen vacancy-riched NdVO4/BiVO4 heterojunction with infrared absorption feature for efficient water oxidation

Bismuth vanadate (BiVO4) has been recognized as a favorable photocatalyst for generating oxygen from water decomposition using solar energy. While, BiVO4’s optical activity is limited due to its low charge mobility, high photo-generated electron hole recombination rate and low infrared light response. Herein, an oxygen vacancy-riched NdVO4/BiVO4 heterojunction with infrared absorption feature is successfully prepared by a two-step cation-exchange method using Na5V12O32 nanowire as a precursor. The in-situ growth of BiVO4 on NdVO4 forms a close contact interface, forming a heterojunction structure and generating an internal electric field, and the oxygen vacancies generated during cation-exchange can serve as electron traps, promoting the separation of photogenerated electron-hole pairs at the heterojunction. Furthermore, the enhanced infrared absorption properties of NdVO4, which forms the heterojunction, broaden the spectral response range. As a result, the synergistic effect of improved heterojunctions due to oxygen vacancies and enhanced infrared absorption, the photocatalyst exhibits enhanced photocatalytic oxygen evolution activity under visible and near-infrared light irradiation, with an oxygen evolution rate of 1543.16 μmol h−1 g−1 under visible light, which is 3 times higher than that of bare BiVO4. Oxygen can be generated even under near-infrared light.

Integration of Perylene Diimide into a Covalent Organic Framework for Photocatalytic Oxidation.

Perylene diimides (PDIs) have garnered considerable attention due to its immense potential in photocatalysis. However, manipulating the molecular packing within their aggregates and enhancing the efficiency of photogenerated carrier recombination remain significant challenges. In this study, we demonstrate the incorporation of a PDI unit into a covalent organic framework (COF), named PDI-PDA, by linking an ortho-substituted PDI with p-phenylenediamine (PDA) to control its intermolecular aggregation. The incorporation enables precise modulation of electron transfer dynamics, leading to a ten-fold increase in the efficiency of photocatalytic oxidation of thioether to sulfoxide with PDI-PDA compared to the PDI molecular counterpart, achieving yields exceeding 90%. Electron property studies and density functional theory calculations show that the PDI-PDA with its well-defined crystal structure, enhances π-π stacking and lowers the electron transition barrier. Moreover, the strong electron-withdrawing ability of the PDI unit promotes the spatial separation of the valency band maximum and conduction band minimum of PDI-PDA suppressing the rapid recombination of photogenerated electron-hole pairs and improving charge separation efficiency to give high photocatalytic efficiency. This study provides a brief yet effective way for the improvement of the photocatalytic efficiency of commonly used PDI-based dyes by integrating them into a framework skeleton.

Construction of Z-scheme SbVO4/g-C3N4 heterojunction with efficient photocatalytic degradation performance

As visible light responsive materials, g-C3N4 has become an outstanding research object for photocatalysis due to its facile synthesis, excellent chemical and thermal stability. In this paper, a Z-scheme SbVO4/g-C3N4 heterojunction was successfully constructed by thermal polymerization method. The synthesized SbVO4/g-C3N4 nanocomposite showed efficient photocatalytic activity on tetracycline (TC) degradation. The photocatalytic degradation of TC follows a first-order kinetic model, in which ·O2− and ·OH free radicals play a major role. The formation of Z-scheme heterojunction between SbVO4 and g-C3N4 can effectively promote the separation of photogenerated electron-hole pairs and the generation of ·O2− and ·OH. The photocatalytic removal rate of TC reached 82.3 % within 150 min under visible light. The as-synthesized SbVO4/g-C3N4 heterojunction can still maintain good stability. Furthermore, a photocatalytic degradation mechanism for the SbVO4/g-C3N4 heterojunction is proposed.

Green light all the way: Triple modification synergistic modification effect to enhance the photoelectrochemical water oxidation performance of BiVO4 photoanode

The recombination of photogenerated electron-hole pairs of the photoanode seriously impairs the application of bismuth vanadate (BiVO4) in photoelectrochemical water splitting. To address this issue, we prepared a Yb:BiVO4/Co3O4/FeOOH composite photoanode by employing drop-casting and soaking methods to attach Co3O4/FeOOH cocatalysts to the surface of ytterbium-doped BiVO4. The prepared Yb:BiVO4/Co3O4/FeOOH photoanode demonstrates a high photocurrent density of 4.89 mA cm−2 at 1.23 V versus the reversible hydrogen electrode (RHE), which is 5.1 times that of bare BiVO4 (0.95 mA cm−2). Detailed characterization and testing demonstrated that Yb doping narrows the band gap and significantly enhances the carrier density. Furthermore, Co3O4 serves as a hole transfer layer to expedite hole migration and diminish recombination, while FeOOH offers additional active sites and minimizes surface trap states, thus boosting stability. The synergistic effects of Yb doping and Co3O4/FeOOH cocatalyst significantly improved the reaction kinetics and overall performance of PEC water oxidation. This work provides a strategy for designing efficient photoanodes for PEC water oxidation.

Photoelectrochemical sensor for hypochlorous acid detection based on the MWNTs doped PEDOT loaded with BP5 functionalized gold nanoparticles

Hypochlorous acid concentration anomaly may cause many serious diseases, so the development method to detect HClO high sensitivity and selectivity is of great significance in clinical diagnosis. Among many methods for detecting HClO, photoelectric chemical sensor has the advantages of high sensitivity and strong anti-interference ability, and has been widely used in the field of detecting HClO. Herein, a simple and specific photoelectrochemical sensor was constructed using A1/B1-type pillar[5]arene functionalized Au NPs and multi-walled carbon nanotube-polythiophene composites for the detection of hypochlorous acid. This approach was based on a sulfhydryl-borate ester modified A1/B1 type pillar[5]arene (BP5) as the main body, hypochlorous acid (HClO) as the guest, multi-walled carbon nanotube (MWNTs) conducting polymers doped with poly(3,4-ethylenedioxythiophene) (PEDOT) as the transport bridge and signal amplifier, as well as spherical gold nanoparticles act as the signal reporter. Specifically, the photoelectrochemical efficiency was further enhanced by the localized surface plasmon resonance effect (LSPR) of gold nanoparticles (Au NPs) and the host-guest complexation between BP5 and HClO. The large specific surface area of MWNTs doped with PEDOT significantly enhanced the electrical conductivity and chemical stability of PEDOT, facilitating accelerated electron transfer and mitigating the recombination of the photogenerated electron-hole pairs. Benefiting from the combination of Au NPs, BP5, MWNTs and PEDOT, the sensor exhibited excellent sensitivity with detection range of 0.5–340 μM and a detection limit of 0.17 μM, and distinguished selectivity against 6 interfering substances. Due to the adsorption and removal effects of pillar[5]arenes on heavy metal ions and pollutants in water, as well as their effective catalytic performance, we anticipate that this composite material also has great potential in photoelectrochemical detection, catalysis, and adsorption.

The electronic stopping power of self-irradiated molybdenum in different charge states

Molybdenum is not only an excellent photovoltaic material but also a crucial component in semiconductors. However, its high bandgap restricts its application in optoelectronic devices. This limitation arises primarily because the energy barrier between photogenerated electron-hole pairs cannot be directly overcome by sunlight. Self-irradiation can overcome these barriers, allowing efficient separation of photogenerated electrons and holes, making molybdenum an excellent light-absorbing material. By altering the charge state of molybdenum-based materials, their light absorption can be adjusted. This project aims to systematically study the optical properties and electronic stopping power of molybdenum-based materials in different charge states through theoretical calculations and experiments.

Photoresponse dependence of WS2/Pt Schottky junction on the features of Pt nanoparticles

In this study, we delve into the photoresponsive characteristics of Schottky junctions fabricated through the deposition of Pt nanoparticles (NPs) onto multilayer WS2 sheets grown via chemical vapor deposition. Our analysis encompasses a comprehensive examination of the junction's morphology, structural attributes, and photophysical behavior. Of particular interest is the intricate relationship between the efficiency of hot electron injection and the specific properties of the Pt NPs, namely their density and size. Our findings reveal that Pt NPs effectively extinguish the photoluminescence of WS2, an outcome attributed to the efficient separation of photo-generated electron-hole pairs facilitated by the WS2/Pt Schottky junction. This process, however, does not significantly alter the electronic configuration of WS2. The modulation of exciton radiative decay is shown to be contingent upon the size and density of the Pt NPs, with an average size of 1.27 nm and density of 0.82/nm² yielding the most rapid exciton decay rate of 1.15 ns. This pronounced dependence of exciton dynamics on Pt NPs features can be attributed to the quenching effect exerted by densely packed Pt NPs, which also plays a pivotal role in the injection of hot electrons from Pt to WS2. The enhancement of internal photoemission is evidenced by a pronounced increase in near-infrared photoresponse within the 800–1000 nm range. Furthermore, the optimization of Pt NPs features leads to superior photoresponsive performance in the WS2/Pt Schottky junctions, manifesting as a responsivity of 280 A/W and a detectivity of 7.77 × 1012 Jones at a wavelength of 850 nm. This photoresponse's dependence on Pt NPs features underscores the dual mechanism governing photodetection in the WS2/Pt Schottky junction: a synergistic interplay between hot electron injection and the separation of photo-excited electron-hole pairs.

Enhanced performance of quasi-solid-state silicon-air batteries through light-assisted anodic reactions

Silicon-air batteries (SABs) offer a promising energy storage solution due to their high theoretical energy density, cost-effectiveness, and environmental friendliness. However, practical applications are hindered by limitations in maximum discharge current density and discharge voltage, stemming from intrinsic electrochemical properties of the silicon (Si) anode and surface oxidation kinetics. This study addressed the low maximum discharge current density of SABs by leveraging the Si semiconductor properties and employing a light-assisted strategy. Introducing light to the silicon anode generates photogenerated electron-hole pairs. Furthermore, introducing light to the Si anode allowed for the generation of photogenerated electron-hole pairs. The resulting holes reacted with OH- ions to form hydroxyl radical (OH), which efficiently oxidized the Si surface, thereby facilitating electrochemical reactions. This enhancement increased the anodic reaction kinetics, thereby enhancing the maximum discharge current density of SABs. Furthermore, through this strategy, light-assisted SABs exhibited significant performance improvements: under 1 sun illumination, maximum discharge current density increased by 50.0 %, discharge voltage by 10.0 %, and power density by 45.0 %. Under 3 suns illuminations, these metrics improved further, with maximum discharge current density increasing by 87.5 %, discharge voltage by 20 %, and power density by 200 %. Additionally, quasi-solid-state SABs (QSSSABs) according to this strategy exhibited versatility across various application scenarios, thereby significantly expanding the practical potential of SABs technology.

Toward High-Performance Self-Powered Near-Ultraviolet Photodetection by Constructing a Unipolar Heterojunction.

Constructing a unipolar heterojunction is an effective energy band engineering strategy to improve the performance of photoelectric devices, which could suppress dark current and enhance detectivity by modulating the transfer of carriers. In this work, unipolar heterojunctions of Si/PbI2 and GaSb/PbI2 are constructed successfully for high-performance self-powered near-ultraviolet photodetection. Owing to the unique band offset of unipolar heterojunctions, the transport of holes is blocked, and only photogenerated electrons in PbI2 can flow unimpeded under the driving force of the built-in electric field. Thus, the recombination of photogenerated electron-hole pairs is suppressed, contributing to high-performance near-ultraviolet photodetection. The as-fabricated Si/PbI2 self-powered near-ultraviolet photodetector exhibits a low dark current of 10-13 A, a high Ilight/Idark ratio of 104, and fast response times of 26/24 ms, which are much better than those of the PbI2 metal-semiconductor-metal photodetector. Furthermore, the as-fabricated GaSb/PbI2 unipolar heterojunction photodetector also exhibits impressive self-powered near-ultraviolet photodetection behaviors. Evidently, this work shows the potential of unipolar heterojunctions for next-generation Si-based and GaSb-based high-performance photodetection.

Enhanced photocatalytic efficiency of BaTiO3 augmented by ZnS nanospheres via Type-II heterojunction for methyl orange degradation

The degradation of organic pollutants is significantly influenced by the recombination of photogenerated electron–hole pair, electron transfer and surface area of a photocatalyst. Barium titanate (BaTiO3) exhibits low photocatalytic activity due to the rapid recombination of photoinduced charge carriers. Hence, the photocatalytic performance of BaTiO3 (BTO) nanoparticles was improved by the construction of heterostructure with the addition of ZnS. BaTiO3 and ZnS were prepared using solid-state metathesis (SSM) and hydrothermal methods, respectively. Subsequently, a series of [(1-x)BaTiO3/(x)ZnS, x = 10, 30, 50 and 70 wt%] heterostructures were successfully constructed through a simple calcination method using pre-prepared BaTiO3 and ZnS. The XRD, FTIR, Raman, XPS and HRTEM analyses revealed the formation of heterostructure between the BTO and ZnS. The positron annihilation lifetime spectroscopy (PALS) results suggest the existence of defects within the materials. To explore the photocatalytic activity, the photodegradation of methyl orange (MO) dye was carried out under UV light illumination for 3 h. Among all the compositions, the heterostructure 70 BaTiO3/30 ZnS (BTZS(70-30)) demonstrated remarkable photocatalytic activity (91.38 %) which is 5.3 times higher than the pristine BTO (17.16 %). The improved photocatalytic activity of heterostructures may result from the effective charge carrier separation facilitated by the type –II band alignment structure between BTO and ZnS, as well as surface defects like oxygen (Vo), and sulphur (Vs) vacancies. The lowest photoluminescence of BTZS (70-30) clearly substantiated the observed high photocatalytic activity. The scavenger outcomes validated that superoxide radicals (•O2−) and holes (h+) played predominant role in the degradation of MO and a detailed explanation was provided for the plausible mechanism.

Photoelectrochemical Water Splitting: A Visible-Light-Driven CoTiO3@g-C3N4-Based Photoanode Interface Follows the Type II Heterojunction Scheme.

Harnessing solar energy can be efficiently used to generate hydrogen by photochemical water splitting, which is a sustainable and environmentally benign energy source. Here, a unique visible-light-driven CoTiO3@g-C3N4 (CTOCN)-based photoanode interface has been optimized and developed with modification to follow the type II heterojunction for the enhancement of photoelectrochemical water splitting. Initially, a graphitic carbon nitride-loaded CoTiO3 (with 10 wt % g-C3N4) composite was obtained using a one-pot solvothermal method. Accordingly, the type II heterojunction interface between g-C3N4 and CoTiO3 has been successfully created and confirmed by the acquired phase, morphological, and optical examinations. Thereby, heterostructure generations with interfacial interaction were enabled to decrease photogenerated electron-hole pair recombination, leading to enhanced charge transfer for water oxidation kinetics. The minimal charge transfer resistance and hole relaxation lifetime (p) shown in Nyquist and Bode plots have further confirmed the rapid electron transport across the electrode/electrolyte interfaces, which is attributed to an enhanced absorption of holes for the water splitting process. Additionally, UV-vis spectroscopy, Mott-Schottky analysis, and UPS studies were used to determine the band edge locations of g-C3N4 and CoTiO3. In comparison to previously developed nanohybrids and their equivalents, the CTOCN-d photoanode follows the type II charge transfer mechanism, resulting in a higher photocurrent density of 55.51 mA cm-2.

Nanozyme-mediated signal amplification on g-C3N4/NaBiO3 Z-scheme heterojunction photoelectrode toward ultrasensitive photoelectrochemical immunoassay for prostate-specific antigen

A sandwich-type photoelectrochemical (PEC) immunosensor for prostate-specific antigen (PSA) detection was developed using the g-C3N4/NaBiO3 (CN/NBO) Z-scheme heterojunction as the photoelectrode and glutathione-Cu/Cu2O nanozyme (GSH-Cu/Cu2O NPs) as the signal amplifier. The unique Z-scheme charge-carrier migration pathway of the CN/NBO heterojunction significantly promotes the separation and migration of photogenerated electron-hole pairs, producing a high photocurrent response of the photoelectrode. GSH-Cu/Cu2O NPs with ascorbic acid oxidase (AAO) activity were introduced into the PEC immunosensing system through immunoreactions for signal amplification. Signal amplification was achieved through double photocurrent quenching of the GSH-Cu/Cu2O NPs on the photoelectrode. On the one hand, GSH-Cu/Cu2O NPs as AAO catalyzed ascorbic acid (AA), an electron donor in the PEC system, to produce dehydroascorbic acid (DHA), leading to a decrease in the photocurrent response. On the other hand, the GSH-Cu/Cu2O NPs prevented AA transfer from the detection solution to the interface of the photoelectrode, further aggravating the PEC signal quenching effect. Benefiting from the excellent performance of the Z-scheme heterojunction-based photoelectrode, the dual signal quenching effect of GSH-Cu/Cu2O NPs, the PEC immunosensor showed an ultralow detection limit of 5.1 × 10−15 g mL−1. By coupling a Z-scheme heterojunction-based photoelectrode with a nanozyme-mediated signal amplification strategy, this study provides a novel avenue for the construction of ultrasensitive and convenient biosensing systems.

Visible-Light Photocatalytic Degradation Efficiency of Tetracycline and Rhodamine B Using a Double Z-Scheme Heterojunction Catalyst of UiO-66-NH2/BiOCl/Bi2S3.

BiOCl is a promising photocatalyst, but due to its weak visible light absorption capacity and low photogenerated electron-hole pair separation rate, its practical application is limited to a certain extent. In this study, a novel double Z-scheme heterojunction UiO-66-NH2/BiOCl/Bi2S3 catalyst was constructed to broaden the visible light response range and promote high photogenerated hole-electron separation of BiOCl. Its photocatalytic performance is evaluated by dissociating tetracycline (TC) and rhodamine B (RhB) in visible light. The optimal proportion of UiO-66-NH2/BiOCl/Bi2S3 hybrids exhibits the best degradation efficiency of visible light illumination (∼93% in 120 min for TC and ∼98% in 60 min for RhB). The synergistic effect of a large visible light response range and the Z-scheme charge transfer mechanism ensure the excellent visible photocatalytic activity of UiO-66-NH2/BiOCl/Bi2S3. It is proven that h+ and •O2- are the main active substances in the photocatalysis process by active substance capture experiments and electron spin resonance tests. The intermediates and degradation processes are analyzed by high-performance liquid chromatography-mass spectrometry. This study proves that the new UiO-66-NH2/BiOCl/Bi2S3 photocatalyst has great application potential in the field of water pollution degradation and will provide a new idea for the optimization of BiOCl.

Integrating Pt nanoparticles with 3D Cu2- x Se/GO nanostructure to achieve nir-enhanced peroxidizing Nano-enzymes for dynamic monitoring the level of H2O2 during the inflammation.

The treatment of wound inflammation is intricately linked to the concentration of reactive oxygen species (ROS) in the wound microenvironment. Among these ROS, H2O2 serves as a critical signaling molecule and second messenger, necessitating the urgent need for its rapid real-time quantitative detection, as well as effective clearance, in the pursuit of effective wound inflammation treatment. Here, we exploited a sophisticated 3D Cu2- x Se/GO nanostructure-based nanonzymatic H2O2 electrochemical sensor, which is further decorated with evenly distributed Pt nanoparticles (Pt NPs) through electrodeposition. The obtained Cu2- x Se/GO@Pt/SPCE sensing electrode possesses a remarkable increase in specific surface derived from the three-dimensional surface constructed by GO nanosheets. Moreover, the localized surface plasma effect of the Cu2- x Se nanospheres enhances the separation of photogenerated electron-hole pairs between the interface of the Cu2- x Se NPs and the Pt NPs. This innovation enables near-infrared light-enhanced catalysis, significantly reducing the detection limit of the Cu2- x Se/GO@Pt/SPCE sensing electrode for H2O2 (from 1.45 μM to 0.53μM) under NIR light. Furthermore, this biosensor electrode enables in-situ real-time monitoring of H2O2 released by cells. The NIR-enhanced Cu2- x Se/GO@Pt/SPCE sensing electrode provide a simple-yet-effective method to achieve a detection of ROS (H2O2、-OH) with high sensitivity and efficiency. This innovation promises to revolutionize the field of wound inflammation treatment by providing clinicians with a powerful tool for accurate and rapid assessment of ROS levels, ultimately leading to improved patient outcomes.

Boosting visible-light-driven photocatalytic H2 production by optimizing surface hydrogen desorption of NiS/CdS–P photocatalyst

Metal chalcogenides are regarded as favorable H2-evolution cocatalysts; however, they often exhibit unfavorable H desorption characteristics due to the strong affinity of nascent H and highly electronegative S sites, which significantly inhibit H2 generation. To address this issue, a general approach to electron-enriched control of sulfur-active sites is developed for weakening the strong interaction of S–H bonds. This is achieved through the formation of a nanostructured model composed of NiS/CdS–P, in which the surface phosphorus (P) atoms are incorporated in CdS NRs to create an imbalanced charge distribution and a localized built-in electric field in the crystal structure of CdS. In this situation, the built-in electric field not only separates the photogenerated electron hole pairs, but it also accelerates the photogenerated electrons from the CdS–P conduction band to the NiS surface for rapid hydrogen reduction rather than hydrogen adsorption. Photocatalytic tests show that the resultant NiS/CdS–P photocatalyst displays a significant H2-generation rate of 44.39 mmol g−1 h−1 and an apparent quantum efficiency of 41% at 420 nm. Valance band XPS analysis shows that CdS–P has a higher electron density than CdS, leading to the production of electron-rich Sδ− active centers. This better photocatalytic hydrogen generation might be due to the synergistic impact of tailoring the intrinsic built-in electric field for the acceleration of photogenerated charges by P-doping and the fabrication of a NiS cocatalyst for hydrogen reduction rather than hydrogen adsorption. The concept of optimizing the electron densities of active sites by morphology tailoring, with an extra built-in electric field, gives a method for rationally constructing artificial photocatalysts for solar power conversion.