Oxidation Sites Research Articles

Rich Sulfur Vacancies and Reduced Schottky Barrier Height Synergistically Enable Au/ZnIn2S4 with Enhanced Photocatalytic CO2 Reduction into CO.

Constructing the plasmonic metal/semiconductor heterostructure with a suitable Schottky barrier height (SBH) and the sufficiently reliable active sites is of importance to achieve highly efficient and selective photocatalytic CO2 reduction into hydrocarbon fuels. Herein, we report Au/sulfur vacancy-rich ZnIn2S4 (Au/VSR-ZIS) hierarchical photocatalysts, fabricated via in situ photodepositing Au nanoparticles (NPs) onto the nanosheet self-assembled ZnIn2S4 (ZIS) micrometer flowers (MFs) with rich sulfur vacancies (VS). Density functional theory (DFT) calculations confirm that for the Au/VSR-ZIS system, the Au NPs serve as the reaction sites for H2O oxidation, and the VSR-ZIS MFs serve as those for CO2 reduction. The rich VS in the Au/VSR-ZIS hybrid can reduce its SBH so as to boost more hot electrons in the Au NPs across its Schottky barrier and then inject into the conduction band (CB) of the VSR-ZIS MFs. In addition, VS can also act as the electron sink to trap the photogenerated electrons, retarding the recombination of photogenerated carriers. The two merits effectively enhance the photogenerated electron density in the surface of VSR-ZIS MFs, availing CO2 photoreduction. In addition, the introduction of rich VS in the Au/VSR-ZIS hybrid can offer more active sites, benefiting the CO2 adsorption and accelerating the desorption of CO* from the surface of the photocatalyst. Therefore, under visible light illumination with no sacrificial reagent, the optimum photocatalyst (Au/VSR-ZIS-0.4) presents the enhanced and selective CO2 photoreduction into CO (8.15 μmol g-1h-1 and near 100%), which are superior to those of most of ZIS-based and plasmon-based photocatalysts. The photocatalytic activity is about 40.0-fold as high as that of the Vs-poor-ZIS (VSP-ZIS) MFs. This work contributes a viable strategy for designing highly efficient plasmonic photocatalysts by using the synergism of the anion vacancies and the optimized SBH induced by them.

New insights and reaction mechanisms in the design of catalysts for the synergistic removal of NOx and VOCs from coke oven flue gas: Dual regulation of oxidative properties and acidic sites

The acid and redox sites of the MnCo catalysts are simultaneously fine-tuned by the addition of V. A dual-function catalyst, designated as V0.5Mn5Co5, has been constructed for the synergistic removal of NOx and volatile organic compounds under coke-oven flue gas conditions, which exhibits > 95 % NOx conversion and > 80 % N2 selectivity at 180–300 °C. Meanwhile, it removes 70 % of ethylene at 240 °C. Besides it has excellent sulfur and water resistance. The characterization results indicate that this acid-redox dual sites modulation strategy appropriately weakens the oxidation capacity of the catalysts while increasing the surface acidity of the catalysts. The catalyst mainly performs SCR reaction through the E-R mechanism, and N2O is generated through the transition dehydrogenation of NH3 and NSCR reaction. Ethylene is first adsorbed on the catalyst surface then oxidized to form carbonate species, and finally decomposed to CO2. Ethylene oxidation follows the MvK mechanism. There is a competitive adsorption between NH3 and C2H4, and a mutual inhibition between the SCR reaction and the ethylene oxidation reaction. V0.5Mn5Co5 exhibits excellent synergistic removal of NOx and VOCs in coke oven flue gas compared with commercial VWTi catalysts, which indicates great promise for industrial application.

Barium titanate photocatalysts with silver-manganese dual cocatalyst for carbon dioxide reduction with water.

Titanate photocatalysts with suitable cocatalysts are promising candidates for photocatalytic CO2 reduction, with the use of water as an electron donor. Here, several barium titanates with various compositions were examined, and BaTi4O9 (BT4) was found to be the best photocatalyst with the assistance of an Ag cocatalyst for photocatalytic CO2 reduction to form CO. The photocatalytic activity was further enhanced by the use of MnOx as an additional cocatalyst to construct an Ag-MnOx/BT4 photocatalyst, where Ag and MnOx were selectively deposited at different facets on BT4 crystal and functioned as active sites for CO2 reduction and water oxidation, respectively. As for the oxidative products from water, molecular oxygen (O2) and hydrogen peroxide (H2O2) were obtained.

Unlocking the molecular modifications of plasma-activated water-induced oxidation through redox proteomics: In the case of duck myofibrillar protein (Anas platyrhynchos)

Plasma-activated water (PAW) contains multiple active species that alter the structure of myofibrillar protein (MP) to enhance their gel properties. This work investigated the impact of PAW on the oxidation of cysteine in MP by label-free quantitative proteomics. PAW treatment caused the oxidation of 8241 cysteine sites on 2815 proteins, and structural proteins such as nebulin, myosin XVIIIB, myosin XVIIIA, and myosin heavy chain were susceptible to oxidation by PAW. Bioinformatics analysis, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, subcellular localization, and STRING analysis, indicated that these proteins with differential oxidation sites were mainly derived from the cytoplasm and membrane, and were involved in multiple GO terms and KEGG pathways. This is one of the first reports of the redox proteomic changes induced by PAW treatment, and the results are useful for understanding the possible mechanism of PAW-induced oxidation of MP.

Synthesis and evaluation of a self-standing CuBi2O4/CuO/Fe2O3 electrode for arsenic removal via photoelectrocatalysis

Water contamination by arsenic (As) poses a significant threat to millions of people worldwide. The development of an effective, affordable, and decentralized system for As removal remains a critical need, particularly to treat As at environmentally relevant concentrations. In this study, a self-standing electrode composed of an engineered interface of CuBi2O4/CuO/Fe2O3 was synthesized on fluorine-doped tin oxide (FTO) substrate using electrodeposition and dip-coating techniques. Each layer Bi2O3, CuBi2O4, CuO, and Fe2O3 was characterized photochemically and electrochemically to identify their light harvesting and electron transfer capacities. The efficacy of the CuBi2O4/CuO/Fe2O3 electrode for removing 0.5 mg L−1 As (III) was evaluated under various treatment conditions, including adsorption, photocatalysis (PC), electrocatalysis (EC), and photoelectrocatalysis (PEC). The PEC treatment at 1.0 V vs Ag/AgCl under visible light irradiation exhibited outstanding As removal efficiency of 96.8 %, surpassing PC (40.4 %) and EC (54.5 %). Fundamental evaluation of the removal mechanism revealed that CuBi2O4/CuO/Fe2O3 oxidizes As (III) to As (V) for enhanced adsorption onto iron oxide sites, as confirmed by X-ray photoelectron spectroscopy (XPS), which identified both As (III) and As (V) adsorbed on the surface. These findings underscore the importance of a rational design approach for photoanodes in As adsorption, highlighting the significant role of individual layers.

Long-range charge transfer mechanism of the III2IV2 mycobacterial supercomplex

Aerobic life is powered by membrane-bound redox enzymes that shuttle electrons to oxygen and transfer protons across a biological membrane. Structural studies suggest that these energy-transducing enzymes operate as higher-order supercomplexes, but their functional role remains poorly understood and highly debated. Here we resolve the functional dynamics of the 0.7 MDa III2IV2 obligate supercomplex from Mycobacterium smegmatis, a close relative of M. tuberculosis, the causative agent of tuberculosis. By combining computational, biochemical, and high-resolution (2.3 Å) cryo-electron microscopy experiments, we show how the mycobacterial supercomplex catalyses long-range charge transport from its menaquinol oxidation site to the binuclear active site for oxygen reduction. Our data reveal proton and electron pathways responsible for the charge transfer reactions, mechanistic principles of the quinone catalysis, and how unique molecular adaptations, water molecules, and lipid interactions enable the proton-coupled electron transfer (PCET) reactions. Our combined findings provide a mechanistic blueprint of mycobacterial supercomplexes and a basis for developing drugs against pathogenic bacteria.

Construction of hollow sphere MnOX with abundant oxygen vacancy for accelerating VOCs degradation: Investigation through operando spectroscopycombined with on-line mass spectrometry

To clarify the key role of oxygen vacancy defects on enhancing the oxidative activity of the catalysts, metal–organic frameworks (MOFs) derived MnOX catalysts with different morphologies and oxygen vacancy defects were successfully prepared using a facile in-situ self-assembly strategy with different alkali moderators. The obtained morphologies included three-dimensional (3D) triangular cone stacked MnOX hollow sphere (MnOX-H) and 3D nanoparticle stacked MnOX nanosphere (MnOX-N). Compared to MnOX-N, MnOX-H exhibited higher activity for the oxidation of toluene (T90 = 226 °C). This was mainly due to the large number of oxygen vacancy defects and Mn4+ species in the MnOX-H catalyst. In addition, the hollow structure of MnOX-H not only facilitated toluene adsorption and activation of toluene and also provided more active sites for toluene oxidation. Reaction mechanism studies showed that the conversion of toluene to benzoate could be realized over MnOX-H catalyst during toluene adsorption at room temperature. In addition, abundant oxygen vacancy defects can accelerate the activated oxidation of toluene and the formation of oxidation products during toluene oxidation.

Study on regeneration mechanism of composite adsorbent by Mg-MOF-74-based modified biochar

In this paper, composite adsorbent was prepared from biochar and Mg-MOF-74 by in-situ growth method to investigate regeneration mechanism. The effects of O2 and temperature on regeneration characteristics were investigated by CO2 adsorption properties and characterization techniques, and the optimal regeneration conditions were determined. Regeneration mechanism of adsorbent was revealed by adsorption kinetics and elemental valence analysis. The related wave function parameters were calculated based on DFT to reveal the repair mechanism of the failed oxidation sites from the microscopic level. The mechanism of CO2 adsorption by the repaired oxidation sites was explored based on the regenerated adsorption configuration. It was found that the regeneration performance of the adsorbent exhibited a trend of increasing and then decreasing with the increase of O2 concentration and temperature, and the optimal regeneration conditions were determined to be 5 % O2 concentration and 200 °C. At optimal regeneration conditions, a synergistic interaction between O2 and poly-metals was generated to enhance the adsorbent polarity. O2 also reacted with the adsorbent in a redox reaction to produce new oxygen-containing functional groups and cause pore expansion, the mass transfer and diffusion was enhanced. The oxidation site adsorbed O2 to undergo electron rearrangement and release the adsorbed CO2. Due to the nature of common orbital hybridization between metals, the metals underwent conjugation and synergistic effects with O2 to form tetrahedral co-coordination structures with lower energies. The electron density and electric field effects of the system were enhanced. The former enhanced interaction with CO2 to form carbonate. The latter increased the activity of the neighboring N atom, which in turn generated a stable ring structure with carbonate, and CO2 adsorption was enhanced.

Phosphorus-modulated surface active center reconstruction in cerium oxide for polyols conversion into carbonates

Ionic liquids (ILs) can effectively regulate the surface morphology and acid-base sites of metal oxides, which is of great significance in the preparation of metal oxide nanomaterials. Here, cerium oxide (CeO2) was prepared in phosphonium-based ILs and P-doped CeO2 materials were obtained by doping phosphorous (P) on the surface of CeO2. Moreover, the yield and selectivity for ethylene carbonate (EC) synthesis catalyzed by CeO2 catalyst prepared were 77.26 % and 95.99 % respectively. The results indicated that an appropriate content of P could generate both Lewis acidic and basic sites related to P on the catalyst surface, and P-mediated frustrated Lewis acid-base pairs (FLPs) composed of P-OH as the basic center and Ce3+ as the acidic center was constructed. This work provides a new strategy for preparing novel CeO2 catalysts and regulating acid-base sites on the surface of that.

Charge Transport Approaches in Photocatalytic Supramolecular Systems Composing of Semiconductor and Molecular Metal Complex for CO2 Reduction.

The design of photocatalytic supramolecular systems composing of semiconductors and molecular metal complexes for CO2 reduction has attracted increasing attention. The supramolecular system combines the structural merits of semiconductors and metal complexes, where the semiconductor harvests light and undertakes the oxidative site, while the metal complex provides activity for CO2 reduction. The intermolecular charge transfer plays crucial role in ensuring photocatalytic performance. Here, we review the progress of photocatalytic supramolecular systems in reduction of CO2 and highlight the interfacial charge transfer pathways, as well as their state-of-the-art characterization methods. The remaining challenges and prospects for further design of supramolecular photocatalysts are also presented.

Application of Electro-Activated Dissociation Fragmentation Technique to Identifying Glucuronidation and Oxidative Metabolism Sites of Vepdegestrant by Liquid Chromatography-High Resolution Mass Spectrometry.

Drug metabolite identification is an integrated part of drug metabolism and pharmacokinetics studies in drug discovery and development. Definitive identification of metabolic modification sides of test compounds such as screening metabolic soft spots and supporting metabolite synthesis are often required. Currently, liquid chromatography-high resolution mass spectrometry is the dominant analytical platform for metabolite identification. However, the interpretation of product ion spectra generated by commonly used collision-induced disassociation (CID) and higher-energy collisional dissociation (HCD) often fails to identify locations of metabolic modifications, especially glucuronidation. Recently, a ZenoTOF 7600 mass spectrometer equipped with electron-activated dissociation (EAD-HRMS) was introduced. The primary objective of this study was to apply EAD-HRMS to identify metabolism sites of vepdegestrant (ARV-471), a model compound that consists of multiple functional groups. ARV-471 was incubated in dog liver microsomes and 12 phase I metabolites and glucuronides were detected. EAD generated unique product ions via orthogonal fragmentation, which allowed for accurately determining the metabolism sites of ARV-471, including phenol glucuronidation, piperazine N-dealkylation, glutarimide hydrolysis, piperidine oxidation, and piperidine lactam formation. In contrast, CID and HCD spectral interpretation failed to identify modification sites of three O-glucuronides and three phase I metabolites. The results demonstrated that EAD has significant advantages over CID and HCD in definitive structural elucidation of glucuronides and phase I metabolites although the utility of EAD-HRMS in identifying various types of drug metabolites remains to be further evaluated. SIGNIFICANCE STATEMENT: Definitive identification of metabolic modification sites by liquid chromatography-high resolution mass spectrometry is highly needed in drug metabolism research, such as screening metabolic soft spots and supporting metabolite synthesis. However, commonly used collision-induced dissociation (CID) and higher-energy collisional dissociation (HCD) fragmentation techniques often fail to provide critical information for definitive structural elucidation. In this study, the electron-activated dissociation (EAD) was applied to identifying glucuronidation and oxidative metabolism sites of vepdegestrant, which generated significantly better results than CID and HCD.

Effect of cell sintering temperature on the performance of non-noble metal loaded cerium oxide SOEC anodes

Abstract Introducing methane oxidation reaction into the anode of the high-temperature solid oxide electrolysis cell (SOEC) can reduce the power consumption for water electrolysis. Compared to the traditional conditions of methane oxidation, the methane oxidation catalyst sintered at the SOEC anode, which is closely related to the cell sintering process. This study uses non-noble metals as active sites for methane oxidation, zirconia, and samarium oxides doped ceria as catalyst support and oxygen ion conductors. The effects of anode sintering temperature on the electrochemical performance of SOEC assisted by methane oxidation were investigated. The results indicate that the high-temperature sintering process promotes the performance of the SOEC anode with Ni as the active site, while high temperature harms the performance of the Co-loaded anode. The sintering temperature exhibits a poor effect on the Fe-loaded anode. The Ni exhibits good enhancement of methane oxidation on reducing the electrolysis voltage of SOEC, while Co only exhibits methane oxidation assistance at low-temperature sintering. Differently, Fe has almost no obvious methane oxidation assistance for SOEC, which mainly represents good oxygen evolution performance.

Structure–function characterization of two enzymes from novel subfamilies of manganese peroxidases secreted by the lignocellulose-degrading Agaricales fungi Agrocybe pediades and Cyathus striatus

BackgroundManganese peroxidases (MnPs) are, together with lignin peroxidases and versatile peroxidases, key elements of the enzymatic machineries secreted by white-rot fungi to degrade lignin, thus providing access to cellulose and hemicellulose in plant cell walls. A recent genomic analysis of 52 Agaricomycetes species revealed the existence of novel MnP subfamilies differing in the amino-acid residues that constitute the manganese oxidation site. Following this in silico analysis, a comprehensive structure–function study is needed to understand how these enzymes work and contribute to transform the lignin macromolecule.ResultsTwo MnPs belonging to the subfamilies recently classified as MnP-DGD and MnP-ESD—referred to as Ape-MnP1 and Cst-MnP1, respectively—were identified as the primary peroxidases secreted by the Agaricales species Agrocybe pediades and Cyathus striatus when growing on lignocellulosic substrates. Following heterologous expression and in vitro activation, their biochemical characterization confirmed that these enzymes are active MnPs. However, crystal structure and mutagenesis studies revealed manganese coordination spheres different from those expected after their initial classification. Specifically, a glutamine residue (Gln333) in the C-terminal tail of Ape-MnP1 was found to be involved in manganese binding, along with Asp35 and Asp177, while Cst-MnP1 counts only two amino acids (Glu36 and Asp176), instead of three, to function as a MnP. These findings led to the renaming of these subfamilies as MnP-DDQ and MnP-ED and to re-evaluate their evolutionary origin. Both enzymes were also able to directly oxidize lignin-derived phenolic compounds, as seen for other short MnPs. Importantly, size-exclusion chromatography analyses showed that both enzymes cause changes in polymeric lignin in the presence of manganese, suggesting their relevance in lignocellulose transformation.ConclusionsUnderstanding the mechanisms used by basidiomycetes to degrade lignin is of particular relevance to comprehend carbon cycle in nature and to design biotechnological tools for the industrial use of plant biomass. Here, we provide the first structure–function characterization of two novel MnP subfamilies present in Agaricales mushrooms, elucidating the main residues involved in catalysis and demonstrating their ability to modify the lignin macromolecule.

Construction of rose-type Co/Mo bimetal MOF and MOF-derived W embedded composites: Structure, reactivity, and dynamic simulation

Transition metal organic framework-derived materials are potential catalysts for cycloolefins oxidation, and it is essential to develop them with sufficient intrinsic activity and more efficient structure. Herein, we designed Co/Mo bimetallic MOF with rose-type structure as a support for synthesizing CoMo-ZIF@IL/W catalyst with lamelliform structure and abundant Co, Mo, and W active sites for cyclopentene tandem oxidation to glutaraldehyde. Characterization results reveal that: 1) Mo implantation dramatically increases pore size (2.15 → 28.91 nm) of monometallic MOF Co-ZIF; 2) IL introduction significantly improves active (Co2+ + Co3+) / satellite content ratio from 1.85 to 2.5; 3) MOF morphology can be completely changed through post-synthetic modification via IL, rather than just during the synthesis process. Meanwhile, CoMo-ZIF@IL/W exhibits high activity and excellent reuse properties in cyclopentene oxidation. Remarkably, dynamic simulation supported via detailed kinetic parameters (pre-exponential factors A1–3 = 1.17 × 1012, 1.45 × 108, 9.58 × 106 L mol−1 s−1, activation energies E1–3 = 89.4, 57.82, 86.01 kJ mol−1) and possible synergistic catalysis mechanism of Co/Mo/W active species were first explored.

Fabrication of porous copper oxide nanostructure on nickel foam electrode by a co-precipitation method for non-enzymatic glucose detection

A novel porous copper oxide nanostructure on nickel foam (CuO/NF) electrode has been successfully prepared through a co-precipitation way. The porous CuO structure and nickel foam can be integrated into a three-dimensional ordered and hierarchal CuO electrode sensor. The porous CuO structure contains many loosely packed nanoparticles and the nanochannels, which are beneficial for providing more active sites for electrocatalytic oxidation–reduction reactions. The Cu(III)/Cu(II) pair plays an essential role, which completes the charge transfer during the electrochemically catalyzed reaction. Two Cu(III) ions obtain two electrons from one molecule of glucose, which completes two electron transfers to produce one molecule of gluconic acid lactone. The results of the actual detection of Fetal Bovine Serum indicate that the CuO/NF electrode produced could be utilized for the determination of actual samples.

Mesoporous SnO2-modified electrode for electrochemical detection of luteolin

Conventional methods like chromatography and spectroscopic analysis have limitations in detecting luteolin. However, electrochemical detection shows promise for reliable analysis. In this study, we compared two different morphologies of SnO2 with the same crystal structure for luteolin detection and found that crystal morphology significantly impacts the catalytic reaction. Compared to SnO2 quantum dots (SnO2 QDs), mesoporous SnO2 (m-SnO2) exhibited a larger specific surface area, providing more active sites for oxidation and reduction reactions. Moreover, m-SnO2 had lower impedance, effectively accelerating charge transfer at the electrode surface. Based on these excellent characteristics, m-SnO2/GCE modified electrode demonstrated outstanding performance in detecting luteolin, achieving a sensitivity of 8.5 μA μM-1, a low limit of 0.19 nM and a wide linear range from 0.5 nM to 1,400 nM. Besides, the m-SnO2/GC electrode displayed excellent consistency, reproducibility, durability, repeatability and specificity. Even three-week exposure to atmospheric conditions, the DPV signal stood at 94.1 % of its original peak current. Those enables its excellent application in practical sample detection. This research enhances our understanding of the influence of material structure and interface on catalytic luteolin detection, providing a theoretical foundation for accurate detection in complex systems. These findings should contribute to the development of more efficient, sensitive, and reliable luteolin sensors.

The efficiency of a granular Fe-based metal-organic framework for the persulfate oxidative degradation of levofloxacin, an emerging antibiotic in wastewater

This study presents a novel approach to solve the problems of leaching and regeneration of metal–organic frameworks (MOFs) in water treatment. The researchers developed a modified MOF by encapsulating MIL-88(Fe) with alginate. The modified MOF was then used to activate sulfate radicals with sodium persulfate for the degradation of levofloxacin (LVX) in water. Various characterization techniques, including XRD, FTIR, BET, FESEM, TG and EDS mapping, confirmed the successful synthesis of the modified MOF and revealed its characteristic facets. The catalytic and adsorptive abilities of the modified MOFs were investigated and sodium persulfate was found to be more effective than hydrogen peroxide in the degradation of LVX. Optimal degradation conditions were determined at a pH of 3, a concentration of 2.5 mM Na2S2O8 and a catalyst dosage of 0.75 g/L. The researchers also found that higher temperatures improved the removal of LVX. The granulated MOF showed remarkable stability over five cycles, although the performance gradually decreased, indicating its potential for long-term applications in water treatment. The inhibitory properties of isopropyl alcohol and ethanol suggest that sulfate radicals rather than hydroxyl radicals are involved in the degradation of LVX. In addition, the functional groups of levofloxacin, including the piperazine ring, the carboxylic acid group and the fluorine substituents, were identified as potential initiation sites for oxidation.

Simultaneously Utilizing Excited Holes and Electrons for Piezoelectric-Enhanced Photoproduction of H2O2 from S-Scheme 2D S-Doped VOx/g-C3N4 Nanostructures.

2D/2D step-scheme (S-scheme) piezo-photocatalysts for the production of fine chemicals, such as hydrogen peroxide (H2O2), have attracted significant attention of global scientists owing to the efficiency in utilizing surface piezoelectric effects from 2D materials to overcome rapid charge recombination in photocatalytic processes. In this research, we reported the fabrication of 2D S-doped VOx deposited on 2D g-C3N4 to produce H2O2 via the piezo-photocatalytic process with high production yields at 20.19 mmol g-1 h-1, which was 1.75 and 4.87 times higher than that from solely piezo-catalytic and photocatalytic H2O2 generation. The finding pointed out that adding sulfur (S) to VOx can help to improve the catalytic outcomes by modifying the electronic properties of pristine VOx. In addition, when coupled with g-C3N4, the presence of S limits the formation of graphene in the VOx/g-C3N4 composites, causing shielding effects and pushing the cascade reactions toward water generation in the materials. Besides, the research also sheds light on the charge transport between g-C3N4 and S-VOx under irradiation and how the composites work to trigger the formation of H2O2. The presence of S in the composite systems enhances charge transfer between two semiconductors by strengthening the internal electric fields (IEF) to drive electrons moving in one direction, as demonstrated by density functional theory (DFT) calculations. Moreover, the formation of H2O2 significantly relies on the reduction of oxygen to generate oxygenic radical species at the g-C3N4 sites. Meanwhile, S-VOx provides oxidative sites in the composites to oxidize water molecules to directly or indirectly generate H2O2 or O2, which will further participate in the reactions to produce the final products. This study confirms the validation of S-scheme piezo-photocatalysts, thus encouraging further research on developing heterojunction materials with high catalytic efficiency, which can be used in practical conditions.

Bifunctional colloid based on anchoring reactions in-situ modified electrodes: For electrochemical sensing and HER

In this study, a bifunctional [PtCl6]2−-GO colloidal material was prepared by anchoring [PtCl6]2− by abundant oxygen-containing functional groups in protonated graphene oxide. Two modification strategies, surface overcoating and electrochemical in situ deposition, were adopted to modify the screen-printed carbon electrode (SPCE), foam electrodes (CuF, NiF), respectively, and Pt-rGO, which uniformly covered the electrode surface, was obtained by a simple onestep of reducing [PtCl6]2−-GO. The effectiveness of the modified materials and electrode modification strategies prepared was validated by tinidazole electrochemical detection and hydrogen evolution reaction (HER). The results indicated that the Pt-rGO modified SPCE possessed lower LOD and higher sensitivity for the detection. Furthermore, as for HER, optimized Pt-rGO-modified NiF and CuF required only 26 mV and 76 mV overpotentials in alkaline and acidic solutions, respectively, to obtain current densities of 10 mA cm−2. This was largely ascribed to the synergistic interaction between platinum and rGO, with the synthesized platinum-rGO displaying stronger active sites and higher intrinsic activity. In particular, Pt, which acts as an active center, could offer part of its electron to H2O and adjacent reduced graphene oxide sites, thus promoting strong electrical connections and efficient HER kinetics.

Transcription stress at telomeres leads to cytosolic DNA release and paracrine senescence

Transcription stress has been linked to DNA damage -driven aging, yet the underlying mechanism remains unclear. Here, we demonstrate that Tcea1−/− cells, which harbor a TFIIS defect in transcription elongation, exhibit RNAPII stalling at oxidative DNA damage sites, impaired transcription, accumulation of R-loops, telomere uncapping, chromatin bridges, and genome instability, ultimately resulting in cellular senescence. We found that R-loops at telomeres causally contribute to the release of telomeric DNA fragments in the cytoplasm of Tcea1−/− cells and primary cells derived from naturally aged animals triggering a viral-like immune response. TFIIS-defective cells release extracellular vesicles laden with telomeric DNA fragments that target neighboring cells, which consequently undergo cellular senescence. Thus, transcription stress elicits paracrine signals leading to cellular senescence, promoting aging.