Separation Of Pairs Research Articles

Cc¯ and bb¯ suppression in the glasma

This study investigates the evolution and dissociation dynamics of cc¯ and bb¯ pairs within the preequilibrium, gluon-dominated stage of high energy nuclear collisions. An attractive potential made of a perturbative Coulomb-like term and of a confining term is used to simulate the attractive strong force in the pairs. Besides, we implement the interaction of the pairs with the evolving glasma fields by virtue of the Wong equations. The interaction with the classical color fields dominates the dynamics, causing an increase in pair separation and subsequent dissociation. The observed finite probability of dissociation for these states reveals the intricate interplay between quantum chromodynamics (QCD) dynamics and the suppression of cc¯ and bb¯ states during the preequilibrium stage. The research highlights differences between cc¯ and bb¯ pairs, revealing the role of quark flavor in the dissociation process. Dissociation spectra analysis indicates a peak shift toward higher momentum, reflecting a slight energy gain by the pairs. This investigation provides valuable insights into the complex dynamics of cc¯ and bb¯ pairs in the glasma, which may help in better interpretation of experimental results on further integration with subsequent phases of the created matter. Published by the American Physical Society 2024

Oxygen Vacancies and Lattice Distortion Synergistically Enhanced Piezocatalysis of CaZn2(BO3)2 for Nonantibiotic Pharmaceutical Degradation.

Piezocatalysis, an emerging green and advanced oxidation technology, has recently been widely researched in environmental treatment. However, the limited polarization efficiency of the piezocatalyst is a serious bottleneck for its practical application. The search for an excellent piezocatalyst with a high piezoelectric coefficient and abundant reactive sites remains an urgent task that needs to be developed. Herein, a piezocatalyst, CaZn2(BO3)2 (CZBO), obtained by quenching has an excellent piezocatalysis, which exhibited superior activity for ibuprofen (IBP) and carbamazepine (CBZ) removal with 100% and 83.8% efficiency under ultrasonic cavitation (120 W, 40 kHz) within 36 min, respectively. The outstanding piezocatalytic degradation was attributed to the strong polarization of the material under the synergistic effect of oxygen vacancies (OVs) and lattice distortion, which effectively facilitated the generation of a high concentration of reactive oxygen species (ROS). The lattice distortion induced by O-deficient [BO3] plane units can promote the e- and h+ pair separation and transportation, and the OVs with abundant electron-rich regions can significantly decrease O-O bond activation energy, thus collaboratively contributing to the high production of ROS for IBP and CBZ degradation. This work provides a simple avenue for enhancing piezoelectric polarization based on the OVs and lattice distortion and proposes insights into the reaction mechanisms for degrading nonantibiotic pharmaceuticals in wastewater.

Observation of double J/ψ meson production in pPb collisions at sNN=8.16 TeV

The first observation of the concurrent production of two J/ψ mesons in proton-nucleus collisions is presented. The analysis is based on a proton-lead (pPb) data sample recorded at a nucleon-nucleon center-of-mass energy of 8.16 TeV by the CMS experiment at the CERN LHC and corresponding to an integrated luminosity of 174.6 nb−1. The two J/ψ mesons are reconstructed in their μ+μ− decay channels with transverse momenta pT>6.5 GeV and rapidity |y|<2.4. Events where one of the J/ψ mesons is reconstructed in the dielectron channel are also considered in the search. The pPb→J/ψJ/ψ+X process is observed with a significance of 5.3 standard deviations. The measured inclusive fiducial cross section, using the four-muon channel alone, is σ(pPb→J/ψJ/ψ+X)=22.0±8.9(stat)±1.5(syst) nb. A fit of the data to the expected rapidity separation for pairs of J/ψ mesons produced in single (SPS) and double (DPS) parton scatterings yields σSPSpPb→J/ψJ/ψ+X=16.5±10.8(stat)±0.1(syst) nb and σDPSpPb→J/ψJ/ψ+X=5.4±6.2(stat)±0.4(syst) nb, respectively. This latter result can be transformed into a lower bound on the effective DPS cross section, closely related to the squared average interparton transverse separation in the collision, of σeff>1.0 mb at 95% confidence level. © 2024 CERN, for the CMS Collaboration 2024 CERN

Giant Colloidal Quantum Dot/α-Ga2O3 Heterojunction for High Performance UV-Vis-IR Broadband Photodetector.

Broadband optoelectronics, which extend from the UV to IR regions, are crucial for imaging, autonomous driving, and object recognition. In particular, photon detection efficiency relies significantly on semiconductor properties, such as absorption coefficients and electron-hole pair generation rate, which can be optimized by designing a suitable p-n junction. In this study, we devise giant PbS colloidal quantum dots (G-PbS CQDs) that exhibit high absorption coefficients and broadband absorption. To leverage these exceptional optical properties, we combine G-PbS CQDs with an ultrawide-bandgap semiconductor, α-Ga2O3, and create an efficient G-PbS CQD/α-Ga2O3 heterojunction photodetector that exhibits high performance across the UVC-vis-NIR spectrum range. The resultant heterojunction facilitates efficient electron-hole pair separation at the G-PbS CQD/α-Ga2O3 heterojunction. Furthermore, we utilize transparent graphene electrodes to overcome the limitations of conventional transistor-type device structures and the substantial optical losses induced by opaque metal electrodes. This strategy maximizes the light-collection area and results in an approximately 3-orders of magnitude higher responsivity (55.5 A/W) and specific detectivity (1.66 × 1013 Jones) compared to devices with opaque metal electrodes.

Multilayer structured bismuth silicate inverse opal film with improved piezo-photocatalytic performance for wastewater purification and dyes removal

Suppressing the recombination of photogenerated charge carriers is thought to be possible by combining the photocatalytic method with the piezoelectric action of piezoelectric semiconductors. A new piezo-photocatalyst, Bi2SiO5 inverse opal film, was prepared by inverse template method. The introduction of 3D ordered inverse opal structure was favorable for light harvesting. The unique two-dimensional layered structure of Bi2SiO5 facilitates electron-hole (e--h+) pair separation. The degradation efficiency of Bi2SiO5 inverse opal film is 15 times higher than that of planar- Bi2SiO5 film under UV light alone. When co-excited by UV light and mechanical energy (ultrasonic vibration), the Bi2SiO5 inverse opal film demonstrated a significantly accelerated degradation rate of RhB compared with planar Bi2SiO5 film. The enhanced piezo-photocatalytic efficiency resulted from the effective separation of photogenerated electron-hole pairs in the Bi2SiO5 inverse opal under the inherent piezoelectric field. Consequently, our work offers fresh perspective on piezo-photocatalytic materials based on Bi2SiO5 for effective wastewater treatment.

Synthesis of CuOQDs/g-C3N4/C Composites Via Stem Template Induction and their Photocatalytic Properties

Introduction: The synthesis of bio-templated porous CuOQDs/g-C3N4/C composites with controllable morphology and suitable energy band structure was successfully carried out via a simple thermal condensation and hydrothermal method. Method: Dicyandiamide and cadmium chloride were selected as starting materials, while Hollyhock stem was chosen as the biological template. The results indicated that, in comparison to pure g-C3N4, g-C3N4/C had a rich porous structure and better-photogenerated carrier separation efficiency. The CuOQDs were anchored evenly on the surface of the g-C3N4, thus resulting in the formation of a greater number of reactive sites. Results: The type-Z heterojunction formed between the CuOQDs and g-C3N4/C reduced the energy required for electron transition, thereby facilitating the separation of photo-generated electronhole pairs. The highest photocatalytic degradation efficiency of CuOQDs/g-C3N4/C for tetracycline (TC) was 65.1%, which was 3.3 times that of pure g-C3N4. Conclusion: In the photocatalytic process, the main reactive species is O2−. The CuOQDs/g- C3N4/C synthesized by stem induction in multi-phase heterojunction form has a stable microstructure to improve the charge separation efficiency. Further, it represents practical photocatalytic environmental protection.

Pt loaded CoFe2O4-based nanoparticles for breast cancer treatment with chemodynamic therapy and sonodynamic therapy

Breast cancer is one of the most widespread cancers worldwide in the female population. However, the side effects and toxicity of chemotherapy and radiotherapy are the obstacles to the treatment of breast cancer. Therefore, we developed a Pt loaded CoFe2O4-based nanoparticles (CF@Pt) for breast cancer treatment with chemodynamic therapy (CDT) and sonodynamic therapy (SDT). The Co2+/Co3+ and Fe2+/Fe3+ gave CF@Pt peroxidase-like activity and catalase activity to gain ·OH and O2 in the tumor microenvironment (TME) for CDT. Furthermore, the separation of electron-hole pairs of CF@Pt transferred the O2 into 1O2 in the presence of ultrasound (US) for SDT. The high level of O2 generated by CDT would produce more 1O2 by SDT that promoted the CDT efficiency. Moreover, the addition of Pt limited the recombination of electron-hole pairs and reduced the energy gap to enhance SDT/CDT combination therapy. In addition, CF@Pt could be engulfed by MDA-MB-231 cells and induced the apoptosis while it had good biocompatibility and blood compatibility. This design provided a novel application on the treatment of breast cancer.

3D-Micro-Flower like [formula omitted] Nanoplate Solid Solution: A facile and rapid room-temperature synthesis with excellent photocatalytic decomposition of antibiotics in water

This research addresses the environmental threat posed by residual antibiotics in water and explores the potential of the photocatalytic process as an eco-friendly solution for antibiotic wastewater treatment. Here in, a series of BiOBr1−xClx nanoplate solid solutions with varied Br:Cl molar ratios were synthesized through a simple co-precipitation method. These solid solutions exhibited superior visible-light-driven photocatalytic activity compared to pristine BiOCl and BiOBr. Notably, the BiOBr0.25Cl0.75 sample demonstrated exceptional performance, achieving 89% and 99% degradation efficiency for ciprofloxacin (CIP) and tetracycline hydrochloride (TCH), respectively, within 20minutes under optimum conditions. The outstanding performance is attributed to factors such as a large specific surface area, suitable morphology and band gap, effective separation of photo-generated electron-hole pairs, and the presence of meso-size pores in the structure. Thermodynamic studies confirmed the exothermic and spontaneous nature of the photocatalytic reactions. The proposed degradation pathway of CIP and TCH, along with the photocatalytic mechanism, is elucidated. The solid solution, BiOBr1−xClx, exhibits facile recyclability, robust stability, and excellent adaptability to actual aquatic environments, establishing its potential as a promising eco-friendly photocatalyst for antibiotic pollution control.

Synthesis, characterization and application of MWCNT/TiO2 composite for photocatalytic reduction of benzophenone to benzopinacol

Photocatalytic reactions are widely investigated as a green chemistry approach towards organic molecule synthesis. Herein, we fabricated (MWCNT/TiO2) composite materials which are beneficial in the photocatalytic synthesis of benzopinacol on irradiation with UV-visible light. The precursor-layer-coating (PLC) method was successfully employed to produce a series of composite materials, X%-MWCNT/TiO2, where (X = 2, 4, 6, and 8% w/w). The XRD confirmed major-anatase and minor-brookite TiO2 along with MWCNT in the composite. FE-SEM, HR-TEM, and EDAX revealed the expected composite microstructure, morphology, and compositional details. The nanosized (10 ̶ 30nm), spherically shaped TiO2 particles were seen integrated to the MWCNT surface. The BET-surface area of the mesoporous composites enhanced from 83.77 to 114.39 m2/g as the MWCNT loading increased from 2 to 8%. The optical studies indicated a marginal shift in absorption edge towards longer wavelength with % MWCNT loadings. The band gap (Eg) was reduced and the charge pair recombination rate retarded. The PL, Raman and XPS studies supported the heterojunction formation at the interface. The photocatalytic activity was evaluated based on the % conversion efficiency of benzophenone to benzopinacol in the presence of light and composite as a photocatalyst. The 6%-MWCNT/TiO2 demonstrated the highest photoactivity with an additional 34% and 25% yield in UV and sunlight respectively compared to bare TiO2. The effective light absorption, electronic excitation, charge pair separation and transfer mechanism at the MWCNT/TiO2 interface were responsible for enhanced photoactivity. The current investigation provided a promising strategy to produce hybrid photocatalytic material for organic molecule synthesis.

Solar-driven induced photoelectron remember effect involved in core–shell NiCo2S4@Ni3V2O8 composite electrode with superior electrochemical energy storage for asymmetric supercapacitor

Photo-assisted supercapacitor systems offer a compelling approach to effectively harnessing both solar and electrical energy. In this study, the core–shell heterostructure NiCo2S4@Ni3V2O8 (NCS@NVO) was successfully synthesized for the development of photosensitive supercapacitor electrodes. NCS@NVO demonstrated a pronounced photoelectron memory effect under illumination, attributed to the solar-driven contributions of both NCS and NVO, as photon absorption facilitated electron-hole pair separation and transport. Compared to the specific capacitance in the dark (2292F g−1 at 1 A g−1), the capacitance of the NCS@NVO composite electrode increased dramatically to 3025F g−1 when exposed to light. Moreover, the capacitance retention rate remained remarkably high at 99.83 % after 10,000 cycles at 20 A g−1. In addition, the NCS@NVO hybrid supercapacitor achieved an outstanding energy density of 63.56 W h kg−1 under illumination, alongside a power density of 789.84 W kg−1. This study thoroughly investigated the solar-induced photoelectron memory effect in the NCS@NVO composite electrode for asymmetric supercapacitors, paving the way for the design of high-performance photosensitive nano-electrodes in advanced electrochemical energy storage applications.

A Physically Motivated Framework to Compare the Merger Timescales of Isolated Low- and High-mass Galaxy Pairs Across Cosmic Time

The merger timescales of isolated low-mass pairs (108 < M * < 5 × 109 M ⊙) on cosmologically motivated orbits have not yet been studied in detail, though isolated high-mass pairs (5 × 109 < M * < 1011 M ⊙) have been studied extensively. It is common to apply the same separation criteria and expected merger timescales of high-mass pairs to low-mass systems, however, it is unclear if their merger timescales are similar, or if they evolve similarly with redshift. We use the Illustris TNG100 simulation to quantify the merger timescales of isolated low-mass and high-mass major pairs as a function of cosmic time, and explore how different selection criteria impact the mass and redshift dependence of merger timescales. In particular, we present a physically motivated framework for selecting pairs via a scaled separation criterion, wherein pair separations are scaled by the virial radius of the primary’s Friends-of-Friends (FoF) group halo (r sep < 1 R vir). Applying these scaled separation criteria yields equivalent merger timescales for both mass scales at all redshifts. Alternatively, static physical separation selections applied equivalently to all galaxy pairs at all redshifts lead to a difference in merger rate of up to ∼1 Gyr between low- and high-mass pairs, particularly for r sep < 150 kpc. As a result, applying the same merger timescales to physical-separation-selected pairs will lead to a bias that systematically overpredicts low-mass galaxy merger rates.

Modulating metal-centered dimerization of a lanthanide chaperone protein for separation of light lanthanides

Elucidating details of biology's selective uptake and trafficking of rare earth elements, particularly the lanthanides, has the potential to inspire sustainable biomolecular separations of these essential metals for myriad modern technologies. Here, we biochemically and structurally characterize Methylobacterium (Methylorubrum) extorquens LanD, a periplasmic protein from a bacterial gene cluster for lanthanide uptake. This protein provides only four ligands at its surface-exposed lanthanide-binding site, allowing for metal-centered protein dimerization that favors the largest lanthanide, LaIII. However, the monomer prefers NdIII and SmIII, which are disfavored lanthanides for cellular utilization. Structure-guided mutagenesis of a metal-ligand and an outer-sphere residue weakens metal binding to the LanD monomer and enhances dimerization for PrIII and NdIII by 100-fold. Selective dimerization enriches high-value PrIII and NdIII relative to low-value LaIII and CeIII in an all-aqueous process, achieving higher separation factors than lanmodulins and comparable or better separation factors than common industrial extractants. Finally, we show that LanD interacts with lanmodulin (LanM), a previously characterized periplasmic protein that shares LanD's preference for NdIII and SmIII. Our results suggest that LanD's unusual metal-binding site transfers less-desirable lanthanides to LanM to siphon them away from the pathway for cytosolic import. The properties of LanD show how relatively weak chelators can achieve high selectivity, and they form the basis for the design of protein dimers for separation of adjacent lanthanide pairs and other metal ions.

Ambient Air-Synthesized CsPbBr3 Nanocrystals Coupled with TiO2 Film as an Efficient Hybrid Photoanode for Photoelectrochemical Methanol-to-Formaldehyde Conversion.

Due to its exceptional optoelectronic properties in the visible spectrum, cesium lead bromide (CsPbBr3) perovskite has attracted considerable attention in solar-driven organic transformations via photoelectrochemical (PEC) cells. However, the performance of the devices is adversely affected by electron-hole recombination occurring between a transparent conductive substrate, such as fluorine-doped tin dioxide (FTO), and a perovskite layer. Herein, to mitigate this issue, a compact layer of titanium dioxide (TiO2) was employed as both an electron transport layer and a hole blocking layer to diminish charge recombination while facilitating electron transfer in such perovskite material. At the oxidation peak potential of 0.70 V vs Ag/AgNO3, a hybrid photoanode of CsPbBr3/TiO2/FTO exhibited a significant increase in photocurrent density, from 15 to 41 μA/cm2, compared to a configuration without a TiO2 layer. Furthermore, the introduction of methanol as a hole scavenger in the PEC system using the hybrid photoanode facilitated the separation of electron-hole pairs, which led to an enhanced photocurrent density of 60 μA/cm2 and promoted the production of formaldehyde. High-performance liquid chromatography (HPLC) confirmed the generation of formaldehyde at a concentration of 26.69 μM with a Faradaic efficiency of 92% under an applied potential of 0.50 V vs Ag/AgNO3 for 60 min of PEC reaction. In addition to the enhanced PEC performance achieved from this hybrid photoanode, CsPbBr3 nanocrystals (NCs) in this work were synthesized by the modified one-pot method under ambient air, where highly uniform and high-purity NCs were obtained. This work signifies the groundbreaking exploration of CsPbBr3 NCs with TiO2 as a photoelectrode material in the organic-based PEC cells, which efficiently improved the interfacial charge transfer within the photoanode for the conversion of methanol to formaldehyde, marking a significant advancement in the field.

Green Engineered CuO/SnO2/HNT Composites: Illuminating the Photocatalytic Path for Organic Pollutant Remediation and Zebrafish Embryo Toxicity Evaluation.

Photocatalysis stands out as a promising technique for treating organic contaminants, yet the quest for visible light active composite materials, crafted through cost-effective, eco-friendly, and uncomplicated processes, poses formidable challenges. Here, we introduce a successful endeavor, the synthesis of a CuO/SnO2 (CS) composite via a microwave method, employing Carissa edulis fruit extract as a reducing as well as capping agent. Various loadings of CS-HNT composites were prepared by ultrasonically incorporating CS onto nanotubular halloysite (HNT) clay. Employing a suite of types of characterization, including XRD, XPS, FT-IR, FE-SEM, HR-TEM, ζ potential, UV-vis-DRS, TGA, BET, and EIS, we meticulously explored the morphology, structure, stability, surface area, electrochemical, and optical properties of the developed CS-HNT composites. HR-TEM observations unveiled the formation of a heterojunction between cubic CuO and spherical SnO2 on the HNT clay surface. Optical and EIS analysis highlighted that the 20CS-HNT composite displayed significant absorption in the visible region, efficient electron-hole pair separation, and enhanced interfacial charge transport relative to other loadings. Photocatalytic evaluations and optimization studies revealed that the 20CS-HNT photocatalyst achieved notable removal efficiencies, eliminating 85% of Congo red (CR) and 80% of tetracycline (TC) within 90 min and 74% of ATZ in 3 h under visible light conditions. Scavenging investigations, the fluorescence probe method, and a NBT transformation study underscored the pivotal roles of hydroxyl and superoxide radicals in pollutant removal. The reusability trials highlighted the exceptional stability and recyclability of the photocatalyst, even after five cycles. In addition, zebrafish embryo toxicity tests revealed improved survival and hatching rates in photocatalyst-treated samples compared to those of controls. Moderate toxicity was observed in treated TC, while the treated CR sample showed non-lethal toxicity. In essence, this study unveils a straightforward and efficacious approach for developing photocatalysts for large-scale wastewater treatment. Furthermore, it proposes the adoption of safe clay-based bimetal oxide photocatalysts in diverse environmental applications.

Lattice Distortion Creates Enhancements in Photocatalytic and Electrocapacitive Performance of Sol–Gel‐Derived Cu‐Doped NiTiO3

A remarkable 35% enhancement in the photocatalytic and electrocatalytic abilities of an ilmenite nickel titanate (NiTiO3) material is reported. This boost in catalytic performance is achieved by simply creating a static distortion in the rhombohedral unit cell by replacing a small proportion of a small‐size nondegenerate Ni (69 pm) with a large‐size degenerate Cu (73 pm). The materials are synthesized by using a simple sol–gel method. The appropriate doping amount of Cu facilitates the better separation of intrinsic charge carrier pairs by inhibiting their recombination. The photocatalytic and electrochemical activities of durable materials in aqueous MB dye (10 ppm) and KOH (1 molar) electrolyte solutions are found to be directly associated with this improvement in inherent charge carrier transfer characteristics. The enhanced photodissociation of MB dye (42–56%) and specific capacitance (381–450 F g−1) in a KOH (1 molar) electrolyte are in full accord with the investigations carried out using crystallographic and optoelectronic analysis, charging–discharging measurements, and electrochemical impedance (EIS) spectroscopy investigations. Same material with high textural surface areas or controllable particle morphologies might show a far better photo/electrocatalytic performance in a variety of practical applications.

Construction of Ag-modified ZnO/g-C3N4 heterostructure for enhanced photocatalysis performance.

ZnO/g-C3N4 heterojunction modified with Ag nanoparticles (ZnO/CN/Ag) was synthesized by depositing ZnO nanorods/Ag nanoparticles onto g-C3N4 nanosheets. Under xenon lamp irradiation, 99% of Rhodamine B (RhB) was degraded by ZnO/CN/Ag-5% composite within 30min, which was much higher than the degradation efficiency of ZnO and ZnO/CN. The synergistic effect of g-C3N4 and ZnO, along with the localized surface plasmon resonance effect of Ag NPs, contributes to the improvement of photocatalytic performance. Ag nanoparticle provides another charge transfer path from g-C3N4 to ZnO, which speeds up the separation of electron-hole pairs. Meanwhile, the catalyst had good stability and recyclability. Finite-difference time-domain method and the density functional theory were used to obtain the charge transfer process. The photodegradation process has been studied in depth.

Reducing Dielectric Confinement Effect Enhances Carrier Separation in Two-Dimensional Hybrid Perovskite Photocatalysts.

Two-dimensional organic-inorganic hybrid perovskites (OIHPs) with alternating structure of the organic and inorganic layers have a natural quantum well structure. The difference of dielectric constants between organic and inorganic layers in this structure results in the enhancement of dielectric confinement effect, which exhibits a large exciton binding energy and hinders the separation of electron-hole pairs. Herein, a strategy to reduce the dielectric confinement effect by narrowing the dielectric difference between organic amine molecule and [PbBr6]4- octahedron is put forward. The Ethanolamine (EOA) contains hydroxyl groups, resulting in the positive and negative charge centers of O and H non-overlapping, which generated a larger polarity and dielectric constant. The reduced dielectric constant produces a smaller exciton binding energy (71.03 meV) of (C2H7NO)2PbBr4 ((EOA)2PbBr4) than (C8H11N)2PbBr4 ((PEA)2PbBr4 (156.07 meV), and promotes the dissociation of electrons and holes. The increasing of lifetime of photogenerated carrier in (EOA)2PbBr4 are proved by femtosecond transient absorption spectra. Density functional theory (DFT) calculations have also indicated that the small energy shift of the total density of states (DOS) between the C/H/N and the Pb/Br in (EOA)2PbBr4 favors the separation of electrons and holes. In addition, this work demonstrates the application of (PEA)2PbBr4 and (EOA)2PbBr4 in the field of photocatalytic CO2 reduction.

Fabrication of pyridine incorporated and O-doped g-C3N4/COF: A type-II heterojunction for enhanced hydrogen production under visible light irradiation

The fabrication of heterojunction photocatalysts is important for achieving highly efficient electron transfer, charge separation, and catalytic activity. In this study, we report the successful creation of a type II heterojunction between pyridine incorporated and O-doped g-C3N4 (POCN) and a covalent organic framework (COF). The heterojunction formation significantly reduced the fluorescence intensity of the POCN/COF, indicating effective separation of electron-hole pairs. Additionally, POCN/COF demonstrated excellent interface charge transfer resistance and photocurrent response. Its hydrogen production rate was remarkably high at 3500 μmol g⁻1 h⁻1, about 1.6 times that of pure COF (2200 μmol g⁻1 h⁻1) and 3.5 times that of the physical mixture (1000 μmol g⁻1 h⁻1), and it also exhibited enhanced stability. This indicates that it can be effectively fabricated into a heterojunction of POCN and COF. The optimal value for adding POCN was approximately 5 wt% of COF. This demonstrates greater activity compared to other composite catalysts made from graphitic carbon nitride and COF. This study presents a valuable approach for fabricating reusable heterojunction photocatalytic systems and efficiently generating hydrogen from natural energy sources.

Efficient Catalytic Production of Reactive Oxygen Species through Piezoelectricity in Bismuth Sulfide Rich in Sulfur Vacancies.

Sulfur (S) vacancies in metal sulfides are of interest in electrocatalysis and photoelectronics, but their effect on the generation of reactive oxygen species (ROS) during mechanical catalysis is unclear. This study investigates the impact of S-vacancies in defective bismuth sulfide (Bi2S3-x) on ROS production under ultrasonic irradiation and organic contaminant decomposition. S-vacancies disrupt the centrosymmetric structure of intrinsic Bi2S3, inducing piezoelectric effects and enhancing the electrical energy in Bi2S3-x. The positively charged S-vacancies in Bi2S3-x promote the separation of ultrasound-activated electron-hole pairs by capturing electrons. As a result, the optimal rate of H2O2 formation and the reaction rate constant for degrading Rhodamine B dye on Bi2S3-x are found to be 1.9 and 37 times higher, respectively, than those on Bi2S3 under ultrasonic irradiation. The nonzero catalytic efficiency in centrosymmetric Bi2S3 is due to the flexoelectric catalytic effect from nonuniform strain. These results guide the piezocatalyst design and elucidate mechanical catalysis mechanisms.

Infrared optoelectronics in twisted black phosphorus

Electrons and holes, fundamental charge carriers in semiconductors, dominate optical transitions and detection processes. Twisted van der Waals (vdW) heterostructures offer an effective approach to manipulate radiation, separation, and collection processes of electron-hole pairs by creating an atomically sharp interface. Here, we demonstrate that twisted interfaces in vdW layered black phosphorus (BP), an infrared semiconductor with highly anisotropic crystalline structure and properties, can significantly alter both recombination and separation processes of electron-hole pairs. On the one hand, the twisted interface breaks the symmetry of optical transition states resulting in infrared light emission of originally symmetry-forbidden optical states along the zigzag direction. On the other hand, spontaneous electronic polarization/bulk photovoltaic effect is generated at the twisted interface enabling effective separation of electron-hole pairs without external voltage bias. This is supported by first-principles calculations and repeated experiments at various twisted angles from 0 to 90°. Importantly, these phenomena can be observed in twisted heterostructures with thickness beyond two-dimensional. Our results suggest that the engineering of vdW twisted interfaces is an effective strategy for manipulating the optoelectronic properties of materials and constructing functional devices.