Inorganic Agents Research Articles

Laboratory Evaluation of the Plugging Performance of an Inorganic Profile Control Agent for Thermal Oil Recovery

During the process of steam thermal recovery of heavy oil, steam channeling seriously affects the production and ultimate recovery. In this study, fly ash was used as the plugging agent, and then a series of plugging experiments based on the results of two-dimensional (2D) experiments were conducted to study the effect of plugging the steam breakthrough channels. The experimental results show that the inorganic particle plugging agent made from the fly ash had a good suspension stability, consolidation strength, and injection performance. Because of these characteristics, it was migrated farther in the formation with a high permeability than in the formation with a low permeability, and the plugging rate was greater than 99%. After steam injection, it had a good anti-flush ability and stable plugging performance in the formation. In terms of the oil displacement effect, oil recovery in the formation with a low permeability was effectively improved because of plugging. The results show that the inorganic particle plugging agent could effectively control the steam channeling and it improved the development effect of the heavy oil reservoir.

Effect Evaluation and Action Mechanism Analysis of "Profile Control + Plugging Removal" after Chemical Flooding.

The existing plugging removal operation in JZ9-3 oilfield has the disadvantages of small amount of plugging remover, fast injection speed, and short construction time. Under the condition of injection well suction profile reversal, plugging remover is difficult to enter the low permeability part and play the role of deep plugging removal. In order to improve the plugging removal effect, this paper used the physical simulation method to carry out the experimental study and mechanism analysis on the effect of water flooding, chemical flooding, and plugging removal measures of the multi-layer system combination model. The results showed that the recovery of general plugging removal after chemical flooding increases by only 0.70%, while the recovery of ‘profile control + plugging removal’ increases by ‘9.34% + 2.59%’, and the amount of produced liquid decreases by more than 40%. It can be seen that the combined operation of profile control and plugging removal has dual effects of plugging and dredging and synergistic effect, which not only expands the swept volume, but also reduces the inefficient and ineffective cycles. On this basis, the optimization design and effect prediction of the target well W4-2 plugging removal scheme were carried out by using the numerical simulation method. Recommended scheme: inorganic gel profile control agent volume 13,243.6 m3, produced by the main agent (Na2O·nSiO2), isolation fluid (Water), and auxiliary agent (CaCl2) through multiple rounds of alternating injection into the reservoir. The plug removal agent (K2S2O8) injection volume is 100 m3, the concentration is 0.8%. The post-implementation ‘Output/Input’ ratio is expected to be 3.7.

Enhancing mechanical and antibacterial properties of polycaprolactone nanocomposite nanofibers using decorated clay with ZnO nanorods

AbstractIt is urgently necessitate to develop a construct with desirable mechanical properties and antibacterial activity for biomedical applications. Zinc oxide (ZnO) has emerged as a promising antibacterial inorganic agent for the improvement of biopolymer scaffold properties. However, its agglomeration/aggregation has an adverse effect on its performance. In the present work, clay platelets have served as a substrate for decoration of high density, well‐distributed ZnO nanorods via in‐situ synthesis. Then, polycaprolactone (PCL) nanofibers containing 1%, 2%, 4%, and 6% ZnO nanorods decorated on clay platelets (Clay@ ZnO) are fabricated using the electrospinning technique. The tensile strength and modulus of the PCL scaffold are significantly enhanced by increasing Clay@ ZnO content, thanks to the presence of well‐distributed ZnO rods on exfoliated clay platelets. However, the maximum elongation at break is observed for PCL/1% (Clay@ ZnO). Disc diffusion method reveals that good coverage of clay platelets with ZnO nanorods boosts the antibacterial performance of ZnO against both Staphylococcus aureus and Escherichia coli bacteria strains. Moreover, incorporation of Clay@ ZnO powders into the PCL scaffold considerably enhances its antibacterial activity. Cell culturing assay demonstrates the favorable cytocompatibility of prepared nanocomposite nanofibers by promoting cell attachment and proliferation. Such engineered nanocomposite has a high potential to utilize in biomedical applications.

A Review on Antibacterial Biomaterials in Biomedical Applications: From Materials Perspective to Bioinks Design.

In tissue engineering, three-dimensional (3D) printing is an emerging approach to producing functioning tissue constructs to repair wounds and repair or replace sick tissue/organs. It allows for precise control of materials and other components in the tissue constructs in an automated way, potentially permitting great throughput production. An ink made using one or multiple biomaterials can be 3D printed into tissue constructs by the printing process; though promising in tissue engineering, the printed constructs have also been reported to have the ability to lead to the emergence of unforeseen illnesses and failure due to biomaterial-related infections. Numerous approaches and/or strategies have been developed to combat biomaterial-related infections, and among them, natural biomaterials, surface treatment of biomaterials, and incorporating inorganic agents have been widely employed for the construct fabrication by 3D printing. Despite various attempts to synthesize and/or optimize the inks for 3D printing, the incidence of infection in the implanted tissue constructs remains one of the most significant issues. For the first time, here we present an overview of inks with antibacterial properties for 3D printing, focusing on the principles and strategies to accomplish biomaterials with anti-infective properties, and the synthesis of metallic ion-containing ink, chitosan-containing inks, and other antibacterial inks. Related discussions regarding the mechanics of biofilm formation and antibacterial performance are also presented, along with future perspectives of the importance of developing printable inks.

Preparation and Characterization of Poly(AMPS-co-Aa-co-DEAA)/MMT Nanocomposite Hydrogels

Nanocomposite (NC) hydrogels poly (AMPS-co-AA-co-DEAA)/MMT were prepared by in situ free radical polymerization by using montmorillonite (MMT) as the inorganic cross-linking agent and 2-acrylamido-2-methylpropanesulfonic acid (AMPS), acrylic acid (AA) and N,N-diethylacrylamide (DEAA) as the monomers. Based on the confirmation of the composition and network structure of the nanocomposite hydrogels, the mechanical properties and the swelling behavior in buffers and salt solutions with different pH levels were systematically investigated. The hydrogel had good mechanical properties due to the homogeneous dispersion of MMT. Its tensile strength at break reached 0.1 MPa, and elongation at break reached 1807%. The nanocomposite hydrogel exhibited certain pH and salt-sensitive behavior. As for the structure of the synthetic hydrogel, its morphology was determined by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM).

Biomimetic Exosomes: A New Generation of Drug Delivery System.

Most of the naked drugs, including small molecules, inorganic agents, and biomacromolecule agents, cannot be used directly for disease treatment because of their poor stability and undesirable pharmacokinetic behavior. Their shortcomings might seriously affect the exertion of their therapeutic effects. Recently, a variety of exogenous and endogenous nanomaterials have been developed as carriers for drug delivery. Among them, exosomes have attracted great attention due to their excellent biocompatibility, low immunogenicity, low toxicity, and ability to overcome biological barriers. However, exosomes used as drug delivery carriers have significant challenges, such as low yields, complex contents, and poor homogeneity, which limit their application. Engineered exosomes or biomimetic exosomes have been fabricated through a variety of approaches to tackle these drawbacks. We summarized recent advances in biomimetic exosomes over the past decades and addressed the opportunities and challenges of the next-generation drug delivery system.

The use of inorganic process control agents to mill titanium‑niobium powders suitable for the selective laser melting process

Alloying titanium (Ti) with niobium (Nb) offers the ability to develop a low-stiffness Ti alloy. The established methodologies for the fabrication of powders suitable for SLM processes are based on atomisation processes, which require high volume powder production to be financially viable. Consequently, these are unsuited for small batches used in bespoke alloys (e.g., Ti-Nb alloys). This work highlights the potential for milled powders as a cheaper feedstock for the SLM process. When following the established practice of using organic PCAs, this leads to the creation of interstitial phases during SLM fabrication. To alleviate that, this study puts forward the use of inorganic PCAs, such as tin (Sn) and calcium (Ca), to produce SLM-suitable powder. The use of inorganic PCAs, especially Ca, is effective, rendering the resultant powder with physical properties appropriate for the SLM process. These inorganic PCAs allow the fabrication of homogeneous Ti-Nb alloys with suitable hardness.

Effect of synthesized sulfonate derivatives as nucleating agents on crystallization behavior of poly(lactic acid)

ABSTRACT The improvement of the crystallization of poly(lactic acid) (PLA) is one of the key areas to allow PLA to perform better at higher temperature and load bearing. Due to its slow crystallization rate, either organic or inorganic nucleating agents (NAs) can be used to improve the crystallization rate of PLA. In the case of organic NAs, aromatic sulfonate salt and bisamide compounds are promising ones because they can control better clarity. The aim of this work was to study the crystallization behavior of PLA using as-synthesized dimethyl 5-sulfoisophthalate sodium salt (SSIPA) as a nucleating agent in comparison with the commercial sulfonate salt (LAK-301). Two grades of PLA (PLA L105 and PLA 3251D) were used in this study. PLA samples were prepared by internal mixer and compression molding. All samples were investigated by DSC and POM. The results from DSC showed that after introducing the nucleating agents into PLA, the crystallinity in all samples was improved. The highest crystallinity at 57.48% was obtained from PLA L105/SSIPA1.0. Isothermal crystallization kinetics showed the improvement in overall crystallization rate of PLA with nucleating agents. The lowest half time crystallization obtained was 1.19 min for PLA L105/SSIPA1.0 at 135 °C. The results from POM indicated the substantial increase of the nucleus density and smaller spherulite size upon adding nucleating agents.

Biological Synthesis and Characterization of Silver Nanoparticles by Orthosyphan Rubicundas

There are many metal nanoparticles, usually formed in the range of 1 to 100 nm size. Silver nanoparticles (AgNPs) have the unique properties of silver ions and hence are useful in molecular diagnostics, in therapies, as well as in devices that are used in several medical procedures. The use of plants in the production of AgNPs has drawn attention due to their rapid, eco-friendly, non-pathogenic, economical protocol, and a single-step technique for the biosynthetic processes. Though till date, many researchers have explored biosynthesis of nanoparticles using different species belonging to Lamiaceae. Orthosyphan rubicundas is the plant chosen from this family for the study as it is wildly grown in the as a weed and rarely studied in the nanoparticle synthesis.The silver-based compounds were used as known as non-toxic inorganic antibacterial agents expressing their biocidal properties in many application. For characterization of AgNPs, the physicochemical properties of nanoparticles were studied, which explained the detailed result of their behaviour, efficacy, safety, and biodistribution. Characterization is performed using a variety of analytical techniques, mainly including X-ray Diffractometry (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), and Transmission Electron Microscopy (TEM).

Crystallization behavior of polyvinyl alcohol with inorganic nucleating agent talc and regulation mechanism analysis

Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were used to study the effect of talc on the crystallization properties and morphology of PVA/talc composite films from the perspective of heterogeneous nucleation effect. The Mo Zhishen equation and Avrami equation were used to study the crystallization kinetics behavior, and successive self-nucleation annealing (SSA) method was used to analyze the wafer thickness at various melting temperatures. PVA films were prepared by flow-casting method, and talc was added as inorganic nucleating agent to improve the crystallinity of PVA. The results show that the addition of talc to the PVA film promotes its crystallization, and as the content of the nucleating agent increases, the crystallinity tends to increase. Due to the increase of nucleation point, the proportion of thinner wafers increases, and the gap of wafer thickness becomes smaller, and the wafer thickness becomes uniform. These results show that talc regulates the crystallization of PVA, improves the crystallinity and crystallization rate of PVA. Talc has heterogeneous nucleation effect on PVA films.

Synthesis of phytonic silver nanoparticles as bacterial and ATP energy silencer

Recently, silver nanoparticles have been widely applied in various fields as inorganic antimicrobial agents. This present study adopted a facile, environmentally friendly and cost-effective method to green synthesized silver nanoparticles via the extract of Dioscorea cirrhosa tuber (DCTE-Ag NPs). Green synthesized Ag nanoparticles were characterized by using the transmission electron microscope, X-ray diffraction analysis (XRD), UV–visible spectroscopy (UV–Vis), fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), etc. The results authenticate that the green synthesized Ag NPs were spherical in shape with an average size of 13.87 ± 2.38 nm and have crystalline properties. According to the antibacterial test, the average width of the inhibition zone of green synthesized Ag NPs against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were 14.17 ± 0.84 mm and 13.01 ± 0.72 mm, respectively. The antibacterial property of Ag NPs was further evaluated by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), and the results indicated that they exhibited outstanding antimicrobial activity. Besides, DCTE-Ag NPs has the good bacteriostasis function, which can damage bacterial cells membrane to leak the intracellular contents and inhibit the activity of Na+/K+-ATP-ase to hinder energy conversion.

Studies on Epoxy Resin Modified with Organic Agents

Epoxy composites are one of the most versatile thermosetting polymers widely used due to their strong soldering resistance, high insulation, and thermal resistance. A wide range of raw materials can be used for the preparation of epoxy resins, thus offering a variety of resins with highly controllable performance characteristics. Essentially, epoxy resins are low molecular weight liquids with two or more epoxide functional groups. To get superior properties of the composite material, a broad variety of inorganic and organic modification agents are used. For this study, two protein substances, gelatin, and wheat gluten were used to change the basic properties of three types of epoxy resins. The specific heat of modified epoxy resin materials was performed by using Differential Scanning Calorimetry (DSC) instrument. The thermal analysis was developed on two heatingcooling cycles and the specific heat was evaluated for each segment of the cycle analysis. Also, the mechanical behavior of organic modified polymers subjected to compression was studied using INSTRON compressive testing machine.

Intersection of Inorganic Chemistry and Nanotechnology for the Creation of New Cancer Therapies.

Since its discovery in 1965, the inorganic drug cisplatin has become a mainstay of cancer therapies and has inspired many platinum (Pt)-based compounds to solve various issues of toxicity and limitations associated with the original cisplatin. However, many of these drugs/prodrugs continue to be plagued by an array of side effects, limited circulation, and half-life and off-target effects. To solve this issue, we have constructed an array of platinum-based prodrugs on a Pt(IV) skeleton, which provides more favorable geometry and hydrophobicity, easier functionalization, and ultimately better targeting abilities. Each of these Pt(IV) prodrugs aims to either combine cisplatin with other agents for a combination therapeutic effect or improve the targeting of cisplatin itself, all for the more effective treatment of specific cancers. Our developed prodrugs include Platin-A, which combines cisplatin with the anti-inflammatory agent aspirin, Platin-M, which is functionalized with a mitochondria-targeting moiety, and Platin-B and Platin-Cbl, which combine cisplatin with components to combat cellular resistance to chemotherapy. At the same time, however, we recognize the crucial role of nanotechnology in improving the efficacy of cisplatin prodrugs and other inorganic compounds for the treatment of cancers. We describe several key benefits provided by nanomedicine that vastly improve the reach and utility of cisplatin prodrugs, including the ability of biodegradable polymeric nanoparticles (NPs) to deliver these agents with precision to the mitochondria, transport drugs across the blood-brain barrier, and target cisplatin prodrugs to specific cancers using various ligands. In addition, we highlight our progress in the engineering of innovative new polymers to improve the release patterns, pharmacokinetics, and dosages of cancer therapies. In this Account, we aim to describe the growing need for collaboration between the fields of inorganic chemistry and nanotechnology and how new advancements can not only improve on traditional chemotherapeutic agents but also expand their reach to entirely new subsets of cancers. In addition to detailing the design and principles behind our modifications of cisplatin and the efficacy of these new prodrugs against aggressive, cisplatin-resistant, or metastatic cancers, we also shed light on nanotechnology's essential role in protecting inorganic drugs and the human body from one another for more effective disease treatment without the off-target effects with which it is normally associated. We hope that this perspective into the important intersection between inorganic medicinal chemistry and nanotechnology will inspire future research on cisplatin prodrugs and other inorganic agents, innovative polymer and NP design, and the ways in which these two fields can greatly advance cancer treatment.

Research on Interface Modification and Thermal Insulation/Anticorrosive Properties of Vacuum Ceramic Bead Coating

The thermal insulation effect of the coating was closely related to the content of the thermal insulation filler, but too much filler would cause interfacial compatibility problems of various substances in the coating, micro-defects in the coating, and affect the anti–corrosion performance of the coating. Therefore, solving the interface problem was the key to preparing a coating with heat insulation and anticorrosion functions. In this study, organic–inorganic hybrid polymer was used to modify the surface of vacuum ceramic microbeads, and epoxy–silicone resin was used as the film–forming material to prepare a heat-insulating and anticorrosive coating that can withstand 200 °C. The SEM morphology showed that the interface compatibility of the vacuum ceramic beads modified by the organic–inorganic hybrid agent and the film-forming material were improved, the dispersibility was significantly improved, and the beads were tightly arranged; the thermal conductivity of the coating reached 0.1587 W/(m·K), which decreased by 50% after adding 20% ceramic beads, ANSYS finite element simulation showed that the coating has good thermal insulation performance; after the coating underwent a thermal aging test at 200 °C for 600 h, the microstructure was dense, and the low-frequency impedance modulus was still around 109 Ω·cm2. There was no obvious defect in the microstructure after the alternating cold and heat test for 600 h; the low-frequency impedance modulus was still above 108 Ω·cm2, and the low-frequency impedance modulus of the coating was 1010 Ω·cm2 after the 130d immersion test, indicating that the coating had good heat resistance and anti-corrosion performance.

Nano-Antibacterials Using Medicinal Plant Components: An Overview.

Gradual emergence of new bacterial strains, resistant to one or more antibiotics, necessitates development of new antibacterials to prevent us from newly evolved disease-causing, drug-resistant, pathogenic bacteria. Different inorganic and organic compounds have been synthesized as antibacterials, but with the problem of toxicity. Other alternatives of using green products, i.e., the medicinal plant extracts with biocompatible and potent antibacterial characteristics, also had limitation because of their low aqueous solubility and therefore less bioavailability. Use of nanotechnological strategy appears to be a savior, where phytochemicals are nanonized through encapsulation or entrapment within inorganic or organic hydrophilic capping agents. Nanonization of such products not only makes them water soluble but also helps to attain high surface to volume ratio and therefore high reaction area of the nanonized products with better therapeutic potential, over that of the equivalent amount of raw bulk products. Medicinal plant extracts, whose prime components are flavonoids, alkaloids, terpenoids, polyphenolic compounds, and essential oils, are in one hand nanonized (capped and stabilized) by polymers, lipids, or clay materials for developing nanodrugs; on the other hand, high antioxidant activity of those plant extracts is also used to reduce various metal salts to produce metallic nanoparticles. In this review, five medicinal plants, viz., tulsi (Ocimum sanctum), turmeric (Curcuma longa), aloe vera (Aloe vera), oregano (Oregano vulgare), and eucalyptus (Eucalyptus globulus), with promising antibacterial potential and the nanoformulations associated with the plants’ crude extracts and their respective major components (eugenol, curcumin, anthraquinone, carvacrol, eucalyptus oil) have been discussed with respect to their antibacterial potency.

Research Progress of Light Wavelength Conversion Materials and Their Applications in Functional Agricultural Films.

As new fluorescent materials, light wavelength conversion materials (light conversion agents) have attracted increasing attention from scientific researchers and agricultural materials companies due to their potential advantages in efficiently utilizing solar energy and increasing crop yield. According to the material properties, the light conversion agents can be divided into fluorescent dyes, organic rare-earth complexes, and inorganic rare-earth complexes. The current researches indicates that the fluorescent dyes have relatively high production costs, poor light stability, difficult degradation processes, and easily cause pollution to the ecological environment. The organic rare-earth complexes have short luminescence times, high production costs, and suffer from rapid decreases in luminescence intensity. Compared with fluorescent dyes and organic rare-earth complexes, although rare-earth inorganic complexes have high luminous efficiency, stable chemical properties, and better spectral matching performance, the existing inorganic light conversion agents have relatively poor dispersibility in agricultural films. According to the research on light conversion agents at home and abroad in recent years, this paper first introduces the three common light conversion agents, namely fluorescent dyes, organic rare-earth complexes, and inorganic rare-earth complexes, as well as their uses in agricultural films and their mechanisms of light conversion. At the same time, the preparation methods, advantages, disadvantages, and existing problems of various light conversion agents are classified and explained. Finally, we predict the development trends for light conversion agents in the future by considering six aspects, namely efficiency, cost, compatibility with greenhouse films, light matching, and light transmittance, in order to provide a reference for the preparation of stable and efficient light conversion agent materials.

Enhanced Antimicrobial Cellulose/Chitosan/ZnO Biodegradable Composite Membrane.

In this study, chitosan and sugarcane cellulose were used as film-forming materials, while the inorganic agent zinc oxide (ZnO) and natural compound phenyllactic acid (PA) were used as the main bacteriostatic components to fabricate biodegradable antimicrobial composite membranes. The water absorption and antimicrobial properties were investigated by adjusting the concentration of PA. The scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results demonstrated that the components of the composite membrane were successfully integrated. The addition of ZnO improved the mechanical and antimicrobial properties of the composite membrane, while the addition of PA with high crystallinity significantly reduced the water absorption and swelling. Moreover, the addition of 0.5% PA greatly improved the water absorption of the composite membrane. The results of antimicrobial experiments showed that PA improved the antimicrobial activity of the composite membrane against Staphylococcus aureus, Escherichia coli, Aspergillus niger and Penicillium rubens. Among them, 0.3% PA had the best antimicrobial effect against S. aureus, E. coli and A. niger, while 0.7% PA had the best antimicrobial effect against P. rubens.

Fabrication of novel anti-fouling poly(m-phenylene isophthalamide) ultrafiltration membrane modified with Pluronic F127 via coupling phase inversion and surface segregation

• PMIA/F127 membrane was prepared via NIPS combining with surface segregation. • DFT calculation was employed for designing membrane casting solution. • Influences of F127 on membrane properties were systematically investigated. • The membrane exhibited good separating performance and high antifouling ability. The novel poly( m -phenylene isophthalamide) (PMIA) ultrafiltration membrane with enhanced anti-fouling performance was successfully designed using amphiphilic block copolymer Pluronic F127 via non-solvent induced phase separation (NIPS) technique combined with induced segregation. The influences of Pluronic F127 on PMIA membrane’s microstructure and properties were systematically conducted by employing a series of characterized methods. Meanwhile, the density functional theory (DFT) calculation was employed to study the intermolecular force among the bulk PMIA, Pluronic F127 additive, solvent, and inorganic agent. Results demonstrated that Pluronic F127, functioning as both a porogen and an induced-segregation additive, could effectively affect membrane structure and property. Specifically, the resultant membrane morphologies of the sublayer gradually altered from the finger-like pore to cavity-like shape, and the pore diameter and porosity displayed a stepwise upward trend via increasing the concentration of Pluronic F127, which further induced the loss of the membrane’s mechanical strength. The filtration experiments demonstrated that the water permeation was enhanced, along with the slightly reduced rejection to bovine serum albumin (BSA) with the increasing concentration of Pluronic F127. Furthermore, the fouling resistance and stability were improved remarkably, which benefited from the enhanced hydrophilicity caused by the migration of polyethylene glycol (PEO) segment of Pluronic F127 toward membrane surface and inner-pore wall. Additionally, DFT calculation confirmed the interaction energy among the dope components, which provided theoretical support on the dope design. In summary, the Pluronic F127/PMIA ultrafiltration membrane demonstrated great potential in the field of water purification and wastewater reclamation.

Synthesis–Structure–Activity Relationship in Cu-MOR for Partial Methane Oxidation: Al Siting via Inorganic Structure-Directing Agents

In the pursuit of controlling the propensity of Cu-mordenite (MOR) for the selective oxidation of CH4, we take a closer look at intrinsic zeolite parameters. Via synthesis design, we vary the relative proportion of Al situated near the 8-rings and 12-rings of MOR zeolite. This is accomplished using different Al sources impacting the local degree of silica dissolution and zeolite formation as evidenced by crystallization times and morphological differences. Interrogating the crystalline system with steric probe molecules in conjunction with spectroscopic techniques such as 1H magic angle spinning (MAS) NMR, infrared spectroscopy, as well as temperature-programmed desorption confirms discrete changes of the Al within the unit cell. The subsequent copper exchange allows for the generation of Cu-MOR materials of different inclinations for the activation of methane in the stepwise formation of MeOH. Here, an increasing degree of acid sites in more easily accessible locations (e.g., 12-ring) correlates with increasing maximum productivity toward MeOH at moderate exchange degrees. X-ray absorption spectroscopy supports this notion, finding a higher concentration of self-reduction-resistant framework-associated Cu2+ species, previously established as the active sites in the selective oxidation of CH4.

Plasmon-Accelerated Generation of Singlet Oxygen on an Au/MoS2 Nanohybrid for Enhanced Photodynamic Killing of Bacterial Pathogens/Cancerous Cells.

Benefiting from its strong cytotoxic features, singlet oxygen (1O2) has garnered considerable research attention in photodynamic therapy (PDT) and thus, plenty of inorganic PDT agents have been recently developed. However, inorganic PDT agents consisting of metal/semiconductor hybrids are surprisingly rare, bearing very low 1O2 quantum yield, and their in vivo PDT applications remain elusive. Herein, we provide an unprecedented report that the Au/MoS2 hybrid under plasmon resonant excitation can sensitize 1O2 generation with a quantum yield of about 0.22, which is much higher than that of the reported hybrid-based photosensitizers (PSs). This significant enhancement in 1O2 quantum yield is attributed to the hot-electron injection from plasmonic AuNPs to MoS2 NSs due to the matched energy levels. Electron paramagnetic resonance (EPR) spectroscopy with spin trapping and spin labeling verifies the plasmonic generation of hot charge carriers and reactive oxygen species such as superoxide and 1O2. This plasmonic PDT agent shows a remarkable photodynamic bacterial inactivation in vitro and anti-cancer therapeutic ability both in vitro and in vivo, which is solely attributed to high 1O2 generation rather than the plasmonic photothermal effect. Hence, plasmonic Au/MoS2 with enhanced 1O2 quantum yield and appreciable in vivo cancer plasmonic PDT performance holds great promise as an inorganic PS to treat near-surface tumors. As a first demonstration of how metal localized surface plasmon resonance could enhance 1O2 generation, the present study opens up promising opportunities for enhancing 1O2 quantum yield of hybrid-based PSs, leading to achieving a high therapeutic index in plasmon PDT.