Excellent Activity Research Articles

Europium Oxide Evoked Multisite Synergism to Facilitate Water Dissociation for Alkaline Hydrogen Evolution

AbstractExploring an efficient nonnoble metal catalyst for hydrogen evolution reaction (HER) is critical for industrial alkaline water electrolysis. However, it remains a great challenge due to the additional energy required for H─OH bond cleavage and the lack of enough H2O adsorption sites for most catalysts. Herein, the integration of oxophilic Eu2O3 with NiCo alloy with evoked multisite synergism to facilitate water dissociation for alkaline HER is proposed. The optimized Eu2O3‐NiCo exhibits excellent HER activity with a low overpotential of only 60 mV at 10 mA cm−2 and good electrochemical stability, which is superior to that of Eu2O3‐free NiCo and comparable to benchmark Pt/C. The key roles of Eu2O3 on the enhanced HER performance of Eu2O3‐NiCo are identified by in situ Raman spectroscopy and theoretical calculations. It is discovered that the Eu2O3 with strong oxophilicity facilitates the adsorption of H2O and the breakage of H─OH bonding while evoking the electron redistribution at Eu2O3/NiCo interface and accelerating the Volmer step in alkaline HER. Furthermore, the obtained Eu2O3‐NiCo as both anode and cathode displays excellent overall water‐splitting activity and stability in 1.0 M KOH solution. It is believed that this study provides an important inspiration to design high‐performance electrocatalysts toward HER based on rare‐earth materials.

Au24Cd Nanoenzyme Coating for Enhancing Electrochemical Sensing Performance of Metal Wire Microelectrodes

Dopamine (DA), ascorbic acid (AA), and uric acid (UA) are crucial neurochemicals, and their abnormal levels are involved in various neurological disorders. While electrodes for their detection have been developed, achieving the sensitivity required for in vivo applications remains a challenge. In this study, we proposed a synthetic Au24Cd nanoenzyme (ACNE) that significantly enhanced the electrochemical performance of metal electrodes. ACNE-modified electrodes demonstrated a remarkable 10-fold reduction in impedance compared to silver microelectrodes. Furthermore, we validated their excellent electrocatalytic activity and sensitivity using five electrochemical detection methods, including cyclic voltammetry, differential pulse voltammetry, square-wave pulse voltammetry, normal pulse voltammetry, and linear scanning voltammetry. Importantly, the stability of gold microelectrodes (Au MEs) modified with ACNEs was significantly improved, exhibiting a 30-fold enhancement compared to Au MEs. This improved performance suggests that ACNE functionalization holds great promise for developing micro-biosensors with enhanced sensitivity and stability for detecting small molecules.

Construction of Pd-Te Intermetallic Compounds to Achieve Ultrastable Oxygen Reduction Activity.

Palladium (Pd)-transition metal alloys have the potential to regulate the intermediate surface adsorption strength in oxygen reduction reactions (ORR), making them a promising substitute for platinum-based catalysts. Nonetheless, prolonged electrochemical cycling can lead to the depletion of transition metals, resulting in structural degradation and poor durability. Herein, the synthesis of alloy catalysts (Pd25%Te75%) containing Pd and the metalloid tellurium (Te) through a one-step reduction method is reported. Characterizations of powder X-ray photoelectron spectroscopy, X-ray diffraction, and high-resolution transmission electron microscopy demonstrated both uniform dispersion and strong binding force of elements within the PdTe alloy, along with providing crystallographic details of associated compounds. Based on density functional theory calculations, PdTe had a more negative d-band center than that of pure Pd, which reduces the adsorption capacity between active sites and intermediates in the ORR, and therefore enhances reaction kinetics. The Pd25%Te75% exhibited excellent ORR activity, and its onset and half-wave potentials were ∼0.98 and ∼0.90 V, respectively, at 1600 rpm within the O2-saturated 1.0 M KOH. Significantly, accelerated durability tests achieved exceptional stability, and half-wave potential just decayed by 4 mV after 30000 consecutive cycles. Moreover, this study aims to promote the preparation of Pd and metalloid alloys for other energy conversion applications.

Noncovalent Assembly Strategy for Efficient Synthesis of Dual‐Atom Catalysts

AbstractDiatomic catalysts (DACs), as a frontier of research on atomically dispersed catalysts, have drawn great attention, especially in electrocatalysis. However, most of the current synthetic strategies for DACs suffer from poor efficiency and high cost. In this work, a novel noncovalent assembly strategy is reported for the efficient synthesis of DACs. By the aid of two kinds of noncovalent intermolecular force, the π–π stacking and Coulomb forces, a pair of metal complex ions with opposite electrical charges is spontaneously loaded onto the carbon substrate and transformed into diatomic sites via thermal treatment. This noncovalent assembly approach shows universal feasibility for a broad spectrum of DACs (Ir–Fe, Pt–Fe, Pt–Co, and Pt–Ni). To prove the practical utility, the as‐prepared PtFe‐DAC is deployed as oxygen reduction reaction catalyst, performing excellent activity with a half‐wave potential of 0.935 V (vs RHE) and a 2.3 times higher turnover frequency than that of the single‐atomic Fe‐SAC. In situ characterization and theoretical calculation indicate that the adjacent Pt sites could endow moderate activation of oxygen molecule on Fe sites by lowering the electron pairing energy as well as the modulation of the d‐band center and spin states of Fe centers propelling the desorption of the intermediates.

Selective metallization of polymer based on nanoscale tungsten oxide laser activators for advanced electronics

In recent years, laser-induced selective metallization (LISM) has been widely used to fabricate complex metal patterns and circuits due to its superior precision. Laser sensitizers known as laser-activated for electroless copper plating (ECP) are a significant premise in LISM. Herein, we confirmed that tungsten oxides (WO2.72, WO2.92, and WO3) exhibited excellent LISM activity due to oxygen vacancies (OVs) in their lattice. Moreover, non-stoichiometric tungsten (WO2.72, WO2.92) presented higher activity due to a higher concentration of OVs than the stoichiometric form of WO3, indicating the importance of OVs to the activity of laser sensitizers in LISM. Moreover, a higher OVs concentration in the laser sensitizer resulted in a higher LISM activity. This finding points out the direction for future laser sensitizer screening, synthesis, and development. After 30 min ECP, the square resistance of the prepared copper layer on ABS/WO2.72, ABS/WO2.92, and ABS/WO3 are 0.014, 0.035, and 0.176 Ω/sq, respectively. The nanoscale tungsten oxides with excellent LISM activity enabled the rapid fabrication of metal patterns and circuits in various scenarios, which expands the research field and application prospect of LISM technology. We demonstrate the advantages of LISM with tungsten oxides in fabricating advanced electronics. A strategy for replacing hand-wound windings in electromagnetic generators with 2D on-chip planar inductor arrays from LISM was proposed. The generated current reached a high level of 193 mA, and can be directly connected to wireless sensor networks to supply power. This work is the first research ever reporting laser sensitizers of tungsten oxides and introducing LISM technology into self-powered electronics.

Exploring transition metal hydroxides performance in membrane-free electrolyzer based decoupled water splitting for step-wise production of hydrogen and oxygen

Alkaline decoupled electrolysis is an emerging safest approach for efficient green hydrogen production. Bifunctional electrocatalysts subjected to reverse polarity can be effectively used as the gas-evolving electrodes (GEE) in decoupled water electrolysis for generating both hydrogen and oxygen at different rates and at different times. Designing a bifunctional electrocatalyst with excellent activity and durability will successfully pave the way towards non-precious metal-based decoupled electrolysis systems. Here, for the first time, ternary NiFeMn layered hydroxide is presented as the bifunctional electrocatalyst associated with the β-Ni(OH)2 solid-state redox mediator (SRM) for independently generating hydrogen and oxygen in an alkaline solution without membranes. This electrocatalyst had shown low overpotentials in HER (230 mV at 10 mA/cm2) and OER (270 mV at 50 mA/cm2). In this work, a chemically synthesized hexagonal β-Ni(OH)2 nanosheet was employed as the solid-state redox mediator for fabricating the membrane-free electrolysis setup. Accompanying a bifunctional electrocatalyst in decoupled electrolysis, this device displayed a 1.91 V cell voltage at 10 mA/cm2. When considered together, the complexity and expense of the electrolyzer were decreased by using NiFeMn LH/NF as a bifunctional electrocatalyst. This approach can be considered for constructing a cost-effective and step-wise green hydrogen harvesting system of membrane-free water electrolyzer.

Multi-Faceted Exploration of Amide-Amine Tethered 1,2,3-Triazole Conjugates as antimicrobial agents using synthetic, in vitro and in silico approach

In the present manuscript, diversely substituted amine-amide linked 1,2,3-triazoles were synthesized and investigated as anti-microbial agents. Their molecular structures were established using different spectroscopy techniques including FTIR, 1H NMR, 13C NMR. Finally, the composition was confirmed by employing high resolution mass spectrometry technique. The global reactivity parameters for all the synthetics were assessed by optimizing their ground state geometry using density functional theory (DFT). The anti-microbial efficacy of synthesized compounds was examined against a variety of microbial strains including gram positive, gram negative and fungal strains. The results of in vitro assay revealed moderate to excellent inhibition of anti-microbial growth by the developed synthetics. Among all, compounds 7r displayed highest inhibition of S. aureus, B. subtilis and E. coli growth with an MIC value of 0.0595 µmol/mL (Norfloxacin= 0.0783 µmol/mL). As far as inhibition of fungal growth is concerned, the compound 7o was found to have excellent activity against C. albicans and R. oryzae with an MIC value of 0.0295 µmol/mL (Fluconazole = 0.0408 µmol/mL). The experimental findings of in vitro experiments were validated using molecular docking and dynamics studies. The drug like features including oral bioavailability of the developed synthetics was assessed using ADME, which pay a new way towards drug development process.

Engineering 0D/2D design of zinc sulfide quantum dots encapsulated with yttrium tungstate nanosheets for improving decomposition of organic dyes and doxycycline hydrochloride drug

Herein, it is demonstrated that 0D/2D design of zinc sulfide quantum dots encapsulated with yttrium tungstate nanosheets, which were subsequently used to increase the removal of brilliant blue (BB), methyl red (MR) dyes and doxycycline drug using UV–visible light. The produced ZnS-Y2WO6 nanohybrids exhibited excellent catalytic activity, reaching degradation efficiencies of around 89.92%, 80% and 85.51 % for BB, MR dyes and doxycycline drug, respectively, with a minimum irradiation duration of 120, 60 and 125 min. These nanohybrids outperformed Y2WO6 in terms of photocatalytic efficacy due to enhanced light absorption, efficient charge transfer, and decreased charge carrier recombination between ZnS and Y2WO6 nanoparticles. The synergistic combination of ZnS and Y2WO6 nanoparticles resulted in multiple active sites on the composite surface. Furthermore, the ZnS-Y2WO6 nanohybrids maintained excellent degradation efficiencies of 79.45% and 70.12% for BB and MR dyes, respectively, even after five consecutive cycles, with no significant loss of catalytic activity. The produced ZnS-Y2WO6 nanohybrids were thoroughly analyzed utilizing a variety of analytical methods. Furthermore, the degradation of organic dyes and doxycycline drug related possible mechanism were examined using experimental data, indicating the potential of ZnS-Y2WO6 nanohybrids as excellent photocatalytic materials for oxidizing organic dyes and drugs in aquatic conditions

Innovative approach for trace level detection of mefenamic acid by ferrite nanocomposite-based electrochemical sensor

In the present work, the rapid and highly efficient catalyst has been designed for the electrochemical sensing of the non-steroidal drug Mefenamic acid (MFA) for quality control and clinical assessment. Ferrite nanocomposite (SFBF-NC) has been synthesized by sol-gel method from the precursor sodium ferrite and barium ferrite and applied for the electrochemical sensing of MFA. The SFBF-NC was examined by various analytical methods to confirm its coral-like shape with a highly rough and porous structure, cubic/spinal phase crystallinity, and average crystalline size < 60 nm with good stable electronic properties. Due to the large electroactive surface area, fast electron transfer rate, and potent electrocatalytic activity of SFBF-NC, the fabricated SFBF-NC/GCE showed good sensitivity for the quantitative determination of MFA. The proposed sensor showed the limit of detection (LOD) of 2.12 nM with a linear range of 0.01–450 μM for MFA detection. Additionally, the proposed sensor demonstrated excellent catalytic activity, stability, repeatability, and selectivity for MFA sensing and was utilized for the routine analysis of MFA in biological and pharmaceutical samples.

Stepwise co-assembled biomimetic hydrogel with antibacterial, angiogenesis, and tissue regeneration acceleration for diabetic wound healing

Bacterial infections and inadequate tissue regeneration capacity are prevalent issues in diabetic wounds, impeding the healing process. To solve these problems, a biomimetic hydrogel combined with bacterial cellulose (BC), recombinant human collagen type III (RHC), and ε-poly-L-Lysine (EPL) is fabricated by stepwise co-assembly technology. Owing to the RHC and EPL modifications of BC, the biomimetic hydrogel exhibited antibacterial effects and promoted fibroblast proliferation and angiogenesis, which accelerated the healing of diabetic wounds. Biomimetic hydrogels exhibit good mechanical properties and excellent water absorption, that can protect wounds and provide a moist environment. In addition, in vitro studies have shown that the hydrogels exhibit excellent antibacterial activity and biocompatibility. In vivo studies on diabetic wound healing have shown that biomimetic hydrogels can promote angiogenesis, accelerate collagen deposition, and re-epithelialize wound sites to promote wound healing. This study provides a new and promising strategy for the treatment of diabetic wounds.

Temperature- and pH-induced dual-crosslinked methylcellulose/chitosan-gallol conjugate composite hydrogels with improved mechanical, tissue adhesive, and hemostatic properties

Gauze or bandages are commonly used to effectively control bleeding during trauma and surgery. However, conventional treatment methods can sometimes lead to secondary damages. In recent years, there has been increased interest in developing adhesive hemostatic hydrogels as a safer alternative for achieving hemostasis. Methylcellulose (MC) is a well-known thermo-sensitive polymer with excellent biocompatibility that is capable of forming a hydrogel through physical crosslinking owing to its inherent thermo-reversible properties. However, the poor mechanical properties of the MC hydrogel comprising a single crosslinked network (SN) limit its application as a hemostatic material. To address this issue, we incorporated a chitosan-gallol (CS-GA) conjugate, which has the ability to form chemical crosslinks through self-crosslinking reactions under specific pH conditions, into the MC hydrogel to reinforce the MC hydrogel network. The resulting MC/CS-GA hydrogel with a dual-crosslinked network (DN), involving both physical and chemical crosslinks, exhibited synergistic effects of the two types of crosslinks. Thus, compared with those of the SN hydrogel, the composite DN hydrogel exhibited significantly enhanced mechanical strength and tissue adhesive properties. Moreover, the DN hydrogel presented excellent biological activity in vitro. Additionally, in rat hepatic hemorrhage models, the DN hydrogel exhibited high hemostatic efficiency, showcasing its multifunctional capabilities.

Deciphering the eg occupancy descriptor on perovskite oxides for lithium-sulfur batteries

The partially filled d orbital of transition metal-based catalysts demonstrate excellent catalytic activity against polysulfides. However, an appropriate descriptor to reveal their structure-activity relationship is lacked. This study proposes a quantitative relationship between the eg occupancy of perovskite oxides and polysulfide catalytic activity, serving as an activity descriptor. LaCoO3, with a moderate eg occupation (t2g5eg1.08), demonstrates effective polysulfide anchoring and facilitated redox kinetics conversion compared to LaCrO3 (t2g3eg0) and LaFeO3 (t2g3eg2), showcasing exceptional catalytic performance. The degree of eg occupancy significantly influences the polysulfides adsorption strength, with empty or fully filled eg orbitals resulting in either strong or weak adsorption, respectively. LaCoO3-based batteries exhibit remarkable reversible capacity over 700 cycles at 1.0C, with a minimal capacity fading rate of 0.065% per cycle. This work elucidates the crucial role of eg descriptor for evaluating the adsorption and conversion on polysulfides, offering insights into the development of innovative lithium-sulfur electrocatalysts.

NiAlFe catalysts based on hydrotalcite-like precursors for low temperature CO2 methanation: Electronic effects among components and intrinsic activity of Ni site

NiAlFe catalysts based on the hydrotalcite-like precursor were prepared and the catalysts exhibit excellent low temperature catalytic activity for CO2 methanation. CO2 conversion over the NiAlFe0.3 catalyst is nearly 80 % under the condition of T = 225 °C, P = 1 atm, and WHSV = 24000 mL/(g∙h). With the increase in the substitution of Fe for Al, the hydrotalcite-like structure of the catalyst precursor is gradually destroyed; the reducibility of NiO component is promoted; the amount of surface basic site decreases. There is a strong electronic push–pull effect between NiO and Al2O3 in the calcined catalyst, and the electronic effect is weakened with the introduction of Fe because Fe3+ shares the responsibility of Ni2+ for donating electron to Al3+. In the reduced catalysts, the Ni3Fe alloy was formed and the electrons are pushed from Ni0 to Fe0. With the increase in the Fe amount, the number of surface Ni atom decreases, while the intrinsic activity of Ni active site enhances. The number and intrinsic activity of Ni site are the main two factors determining the CO2 methanation activity at low temperature. Moreover, the substitution of Al3+ by Fe3+ is beneficial for the stability of the catalysts by inhibiting the agglomeration of catalyst particle.

Highly efficient CoFe LDO/α-Bi2O3/g-C3N4 heterojunction for photocatalytic elimination of antibiotic pollutants

Efficiently enhancing the photocatalytic activity of graphite carbon nitride (g-C3N4), a promising candidate for pollutants degradation, is of great importance but remains a challenge. Herein, bismuth oxide (Bi2O3) and layered double oxides (i.e. LDO) were applied to improve the photocatalytic performance of g-C3N4 by constructing a ternary CoFe LDO/α-Bi2O3/g-C3N4 heterostructure. Physicochemical characterization results indicate that CoFe LDO/α-Bi2O3/g-C3N4 exhibits large surface area, competitive visible-light harvesting ability and effective separation and transfer efficiency of the photogenerated carriers. Thus, CoFe LDO/α-Bi2O3/g-C3N4 demonstrates the excellent photocatalytic activity for Tetracycline (TC) degradation, achieving approximately 90% degradation within 60 min, and its apparent reaction rate (about 0.03919 min−1) is 1.78, 1.84 and 9.9 times higher than that of CoFe LDO/g-C3N4, α-Bi2O3/g-C3N4 and g-C3N4, respectively. The major active free radicals, namely •O2− and photogenerated h+, are largely responsible for the photocatalytic degradation of TC, as demonstrated by the radical trapping tests and electron spin resource (ESR) measurements. The feasible photocatalytic mechanism for degrading TC by the CoFe LDO/α-Bi2O3/g-C3N4 heterostructure is tentatively proposed.

Bioinspired Core-shell nanospheres integrated in multi-signal immunochromatographic sensor for high throughput sensitive detection of Bongkrekic acid in food

Nowadays, notable progress has been achieved in detecting foodborne toxins by employing nanoenzyme-based lateral flow immunoassay (NLFIA) sensors in point-of-care testing (POCT). It continues to be a major challenge to maximize the enzyme-like performance of nanozymes for educe any potential uncertainties in catalytic process. In this study, we employed a facile and efficient self-assembly approach to fabricate nucleoid-shell structured biomimetic nanospheres CuS@Au-Pt (CAP), which demonstrates enhanced brightness of the colorimetric signal, excellent affinity, and excellent peroxidase activity. The integration of CAP with a competitive-assay NLFIA platform enabled sensitive immunochromatographic detection of bongkrekic acid (BA), with LOD as low as 0.66 ng/mL. After signal amplification through enzyme-like reaction, the detection range was extended around 1-fold. Additionally, CAP-NLFIA effectively detected BA with a recovery rate of 80.96–119.36% for real samples. The study proposes using CAP as a signal reporter in a dual-readout LFIA, which can establish a high throughput sensitive detection platform.

Fabrication of S-scheme graphdiyne (g-CnH2n-2)/carbon-nitrogen vacancies hollow Ni–Fe prussian blue analogues heterojunction for boosting wide spectrum photocatalytic hydrogen evolution

Efficient photocatalytic hydrogen evolution can be achieved by adjusting the morphology and constructing suitable heterojunction. In this work, an 2D/3D S-scheme graphdiyne (g-CnH2n-2)/carbon-nitrogen vacancies hollow Ni–Fe prussian blue analogues (Ni–Fe–CN PBA) heterojunction (GNF-CN) was prepared for photocatalytic hydrogen evolution. Ni–Fe–CN PBA were prepared by chemical etching and high temperature calcination. The hollow structure can realize multiple reflections of incident light and effectively improve the light utilization efficiency. The CN vacancy changes the band structure of Ni–Fe PBA and enhances its light absorption capacity. Graphdiyne nanosheets (GDY) prepared by load ball milling can increase the active site. The key lies in the construction of an S-scheme heterojunction between GDY and Ni–Fe–CN PBA, which effectively consume useless holes and increase the utilization rate of photogenerated electrons. The S-scheme electron transfer path are proved by DFT calculation, work function and in situ XPS. The GNF–CN–20 showed excellent photocatalytic hydrogen evolution activity (3755.02 μmol h−1 g−1) and photostability compared with GDY (1116.54 μmol h−1 g−1). The present study introduces a novel approach for the construction of an S-scheme heterojunction based on GDY and PBA, enabling wide‐spectrum‐responsive photocatalytic hydrogen evolution.

In situ Regulating the Phase Structure of Ce-based Catalytic Sites to Boost the Performance of Zinc-Air Batteries

We report an iodide-induced phase regulation strategy to in-situ synthesize a cerium-based catalyst (Ce-N4O2 SACs) with a high Ce loading (15.9wt.%), radicals scavenging ability and high-density Ce-N4O2 sites on the surface of porous nanocarbon frameworks. The oxygen reduction reaction (ORR) mechanisms on the Ce-N4O2 SACs are recorded by in-situ Raman spectra. Moreover, the density functional theory (DFT) calculations show that the Ce-N4O2 structure can optimize the electronic configuration of Ce and positively promote the activation of adsorbates. As expected, this catalyst delivers excellent ORR electrocatalytic activity and stability (half-wave potential decay ~11mV after cycling for 30k cycles). The assembled primary zinc-air battery demonstrates a remarkable energy density (ED) of 946Wh kgZn-1 and exhibits predominant long-term durability (ED reduction ~3.5% after for 130h). This work shows that rare-earth single-atom catalysts, subjected to regulation encompassing structure-density-configuration-mass transfer, hold great promise in realizing high ED metal-air batteries.

Visible light-enhanced interface interaction for PMS activation towards the removal of emerging organic pollutants: performance, mechanism and toxicity

The peroxymonosulfate (PMS)-based advanced oxidation process is considered as an effective way to remove emerging organic pollutants in the wastewater. However, the heterogeneous catalysts used for PMS activation suffers from low catalytic stability and PMS utilization efficiency. Herein, sulfur-doped cobalt ferrite loaded graphitic carbon nitride (S-CoFe2O4/CN) was firstly synthesized for PMS activation toward the sulfamethoxazole (SMX) removal. The S-CoFe2O4/CN possessed excellent PMS catalytic activity and photocatalytic activity. The first-order kinetic constant (k) of SMX degradation in the presence of visible light reached 0.3564 min−1 with high PMS utilization efficiency (78.3 %). Mechanism analysis elucidated that compared to the original CoFe2O4, sulfur doping created more oxygen vacancies, while visible light further promoted the regeneration of Co(II), Fe(II) and oxygen vacancy, the formation of high-valent iron oxo as well as the reduction of S2- oxidation. In addition, the visible light/S-CoFe2O4/CN/PMS system showed high resistance to inorganic ions, and superior catalytic stability. Both acute and chronic toxicity of treated SMX solution decreased. This study provides an effective system to remove emerging organic pollutants in the wastewater.

Antiviral effects of umbelliferone against viral hemorrhagic septicemia virus in olive flounder (Paralichthys olivaceus)

Viral hemorrhagic septicemia virus (VHSV) poses a significant threat to global aquaculture, prompting ongoing efforts to identify potential drug candidates for disease prevention. Coumarin derivatives have recently emerged as a promising class of compounds effective against rhabdoviruses, which severely impact the aquaculture industry. In this study, we assessed the anti-VHSV activity of umbelliferone (7-hydroxycoumarin) in fathead minnow (FHM) cells and olive flounder Paralichthys olivaceus. Umbelliferone exhibited an EC50 of 100 μg/mL by reducing cytopathic effect, with a maximum cytotoxicity of 30.9% at 750 μg/mL. Mechanistic analyses via a time-course plaque reduction assay revealed that direct incubation with the virus for 1 h resulted in 97.0 ± 1.8% plaque reduction, showing excellent direct virucidal activity. Pretreatment for 4 h resulted in a 33.5 ± 7.8% plaque reduction, which increased with longer incubation times. Cotreatment led to a 33.5 ± 2.9% plaque reduction, suggesting interference with viral binding, whereas postinfection treatment proved less effective. Umbelliferone was prophylactically administered to the olive flounder through short-term (3 days) and long-term (14 days) medicated feeding, followed by a 4-day postinfection period. Short-term administration at 100 mg/kg body weight (bw)/day resulted in the highest relative percent survival (RPS) of 56%, whereas long-term administration achieved a maximum RPS of 44% at 30 mg/kg bw/day. Umbelliferone administration delayed mortality at these doses. Additionally, umbelliferone significantly inhibited the expression of the VHSV N gene during viral challenge, with no observed toxic effects in fish up to an administration dose of 30 mg/kg bw/day for 28 days. Our findings suggest that the protective mechanism of short-term administration of 100 mg umbelliferone against VHSV infection may involve the overexpression of TLR2, MDA5, STAT1, and NF-κB at 24 hours postinfection (hpi). IL-8 and IFN II expression was upregulated, whereas TNF-α, IL-1β, and IFN I expression was suppressed at 24 hpi. The upregulation of ISG15 at 48 hpi may contribute to the inhibition of VHSV replication, whereas the downregulation of Caspase 3 expression at 96 hpi suggests a possible inhibition of virus-induced apoptosis at later infection stages. Overall, umbelliferone exhibited anti-VHSV activity through multiple mechanisms, with the added advantage of convenient administration via medicated feed.

Nanoengineering construction of g-C3N4/Bi2WO6 S-scheme heterojunctions for cooperative enhanced photocatalytic CO2 reduction and pollutant degradation

S-scheme heterojunction photocatalysts featuring efficient charge transport paths provide a promising strategy for cooperative achieving photocatalytic CO2 reduction reaction (CO2RR) and Rhodamine B (RhB) degradation. In this work, S-scheme heterojunctions composed of g-C3N4 nanosheets coated on Bi2WO6 nanosheets were prepared by a one-step hydrothermal method, resulting in broad-spectrum light absorption, high electron–hole separation efficiency, and excellent photocatalytic CO2 reduction and RhB oxidization performance. Mechanistic analysis revealed the formation of a directional charge transport path at the interface of the heterojunction, which maintained a high oxidation and reduction potential and improved the efficiency of photoexcited carrier separation. In particular, the synergistic reaction system showed excellent photoredox activity compared with the two separate half-reactions. The optimal catalyst 15CN/BWO displayed the highest CO2 conversion efficiency, with CO and CH4 generation rates of 4.3 and 2.7 μmol g−1h−1, respectively, and the degradation efficiency of the composite heterojunction was significantly higher than that of its constituent materials. This work provides a new possibility for designing a novel dual-function photocatalytic reaction system.