Evaluation of redox performance of silver and transition metal‐doped ternary ceria oxides for thermochemical splitting of CO2

Synthesis of Ce_0.9M_0.05Ag_0.05O_2‐δ materials (where, M = Ni, Zn, Mn, Fe, Cu, Cr, Co, Zr) via coprecipitation of hydroxide method and examination of these materials toward multiple thermochemical CO₂ splitting (CS) cycles is reported in this paper. Physical properties of the derived Ce_0.9M_0.05Ag_0.05O_2‐δ materials were estimated by analyzing the calcined powder using a powder X‐ray diffractometer (PXRD) and scanning electron microscope (SEM). The redox reactivity (RR) of each Ce_0.9M_0.05Ag_0.05O_2‐δ material was also evaluated by conducting high‐temperature thermogravimetric experiments. The inclusion of Ag as an active dopant has improved the RR of all the Ce_0.9M_0.05Ag_0.05O_2‐δ materials as compared with the Ce_0.9M_0.1O_2‐δ materials. Among all the Ce_0.9M_0.05Ag_0.05O_2‐δ materials, Zn5Ag5Ce material was capable of releasing highest amount of O₂ 84.1 μmol O₂/g·cycle and the Cr5Ag5Ce material indicated maximum CO production (151.6 μmol CO/g·cycle). The uppermost CO/O₂ molar ratio equal to 1.89 was observed in case of Cr5Ag5Ce material. The quantity of O₂ released and CO produced by Cr5Ag5Ce material was superior as compared with CeO₂¹ by 30.7 μmol O₂/g·cycle and 62.8 μmol CO/g·cycle, respectively.     

Preparation and characterization of erythritol/polyaniline form‐stable phase change materials containing silver nanowires

Sugar alcohols are promising solid‐liquid phase change materials (PCMs). However, problems such as possible leakage of liquid PCMs, high and unstable supercooling, and low thermal conductivity need to be solved. In this work, a novel form‐stable PCM in which m‐erythritol (ME), polyaniline (PANI), and silver nanowires (Ag NWs) were applied as solid‐liquid PCM, supporting material, and thermal conductive filler, respectively, was successfully prepared in anhydrous ethanol by surface polymerization of aniline. Form‐stable PCM with good form stability could be obtained when the ratio of ME/(aniline + ME) was no more than 78.7 wt%. The melting enthalpy (ΔH_m) of the ME/PANI form‐stable PCMs could attain 234.8 J/g while that of the ME/PANI/Ag NWs form‐stable PCMs was about 220 J/g. In addition, the thermal conductivity of the form‐stable PCM was increased by 61.6% when 7.5 wt% Ag NW was added. Moreover, the supercooling of ME was effectively suppressed from 100°C for pure ME to 60°C, corresponding to an improvement of 40%, for the form‐stable PCM containing 7.5 wt% Ag NWs. The supercooling suppression could be ascribed to that PANI provided great amounts of nucleating centers and improved the nucleation kinetics, and Ag NWs improved the thermal diffusivity and thus increased the crystallization rate.     

Transmutations observed from pressure cycling palladium silver metals with deuterium gas

Hydrogen, deuterium, and helium gases were separately cycled through a Johnson-Matthey purifier containing coiled palladium silver alloy tubing: Pd25Ag (75 wt% Pd and 25 wt% Ag). During the cycling of D₂ gas, evidence of anomalous heat production was observed. However, during the cycling of H₂ and He, very little (H₂) or no (He) unusual heat events were observed. After cycling the D₂ gas through the coiled tubing for several months, Pd25Ag samples showed an increase in Cu and Fe compared with the amounts in unexposed Pd25Ag. Chromium, manganese, and zinc were detected in gas-cycled Pd25Ag samples, whereas they were not detected in unexposed Pd25Ag samples. In particular, Zn was present in the gas-cycled Pd25Ag material in larger quantities than either Cr or Mn. Although a small amount of Cu was present in the Pd25Ag coil before the D₂ gas cycling, 7 times more was present after the cycling. Multiple material characterization techniques were used to obtain both pre-test and post-test elemental composition. The results indicate that novel post-test elements, primarily on the surface, were created by unknown nuclear mechanisms at low energy.     

Active Light-Powered Antibiofilm ZnO Micromotors with Chemically Programmable Properties

Bacterial biofilms are multicellular communities firmly attached to solid extracellular substrates. They are considered the primary cause of huge economic losses, from medicine due to medical implants’ failure to large infrastructure due to enhanced pipe corrosion. Therefore, their eradication is highly desirable. Here, the preparation of ZnO self-propelled micromotors is reported, programming their morphology and motion properties through Ag doping. The ZnO:Ag micromotors actively move upon light irradiation via a self-electrophoretic mechanism, showing excellent light-controlled on/off switching motion. At the same time, the rapid and effective removal of both gram-positive and gram-negative bacteria biofilms from the solid surface is demonstrated, exploiting the well-known antibacterial activity of both Ag and ZnO as well as the enhanced diffusion of the micromotors. The new concept for the low-cost and scalable preparation of chemically programmable Ag-doped ZnO micromotors here illustrated opens a new route toward the formulation of a new class of light-driven semiconducting self-propelled micromotors for environmental applications.     

Self‐Assembly of A Novel Ag48 Cluster Encapsulating an Unprecedented [Mo8O28]8− Anion Template

A novel silver cluster ( SD/Ag48a ) co‐protected by p‐MePhS^? and CF₃COO^? ligands with an in‐situ generated unprecedented [Mo₈O₂₈]^8? template has been synthesized under solvothermal condition. Single‐crystal X‐ray diffraction (SCXRD) and electrospray mass spectrometry (ESI‐MS) were used to determine the atom‐precise structure and solution behavior, respectively. Interestingly, the rare [Mo₈O₂₈]^8? ion observed in the center of SD/Ag48a consists of 8 edge‐shared {MoO₆} octahedra or can be deemed as three {Mo₄O₄} cubes fused together by sharing faces. The UV‐Vis spetcrum exhibits that a high‐energy (HE) wide absorption centered at ca. 365 nm, which can be assinged to intraligand (IL) π→π* transition absorption, whereas the low‐energy (LE) shoulder peak centered at ca. 500 nm can be ascribed to ligand‐to‐metal‐charge‐transfer (LMCT, S 3p→Ag 5 s) transition.     

AMICS在铜矿伴生金银综合回收中的应用

某铜矿石中铜品位为0.53%,其中伴生有价元素金、银的品位分别为0.11 g/t和2.76 g/t,虽然相对较低,但仍具有一定的综合回收利用价值。运用AMICS(Advanced Mineral Identification and Characterization System)对该铜矿中的伴生金银进行了赋存状态研究。查明了该矿石中金银矿物的种类、金银矿物的嵌布特征和嵌布粒度,以及影响它们回收的最主要因素,为其综合回收提供了理论依据。     

Early and Delayed Impact of Nanosilver on the Glutamatergic NMDA Receptor Complex in Immature Rat Brain

Silver nanoparticles (AgNPs) are the one of the most extensively used nanomaterials. The strong antimicrobial properties of AgNPs have led to their use in a wide range of medical and consumer products. Although the neurotoxicity of AgNPs has been confirmed, the molecular mechanisms have not been extensively studied, particularly in immature organisms. Based on information gained from previous in vitro studies, in the present work, we examine whether ionotropic NMDA glutamate receptors contribute to AgNP-induced neurotoxicity in an animal model of exposure. In brains of immature rats subjected to a low dose of AgNPs, we identified ultrastructural and molecular alterations in the postsynaptic region of synapses where NMDA receptors are localized as a multiprotein complex. We revealed decreased expression of several NMDA receptor complex-related proteins, such as GluN1 and GluN2B subunits, scaffolding proteins PSD95 and SynGAP, as well as neuronal nitric oxide synthase (nNOS). Elucidating the changes in NMDA receptor-mediated molecular mechanisms induced by AgNPs, we also identified downregulation of the GluN2B-PSD95-nNOS-cGMP signaling pathway which maintains LTP/LTD processes underlying learning and memory formation during development. This observation is accompanied by decreased density of NMDA receptors, as assessed by a radioligand binding assay. The observed effects are reversible over the post-exposure time. This investigation reveals that NMDA receptors in immature rats are a target of AgNPs, thereby indicating the potential health hazard for children and infants resulting from the extensive use of products containing AgNPs.     

Highly conducting silver nanowire-polyacrylonitrile hollow fibres for flexible supercapacitors

A new approach for making stable, flexible, and conductive hollow fibres of poly (acrylonitrile) using dry-jet-wet spinning technique is investigated, wherein the inner walls of the poly (acrylonitrile) hollow fibres are deposited with silver nanowires using their dispersion in the bore fluid. The bore fluid plays a crucial role in determining the morphology and flexibility of the hollow fibres and entrapment of long silver nanowires on the inner walls. Fibres with AgNW layer having high conductivity of ~10⁴ Scm⁻¹ are obtained with the use of ~2 wt% of silver nanowires. The conducting fibres are successfully assembled into coaxial configuration to yield highly stable, flexible supercapacitors with capacitance value of 128 Fcm⁻³. The unique morphology of these conductive hollow fibres opens the possibility of making flexible and stable devices for wearable electronics.     

无颗粒型银导电墨水的研究进展

无颗粒型银导电墨水因其具有较高的稳定性，较低的后处理温度，在印制电子领域中应用广泛。根据银前驱体的选择不同，综述了以新癸酸银、柠檬酸银、草酸银、碳酸银、醋酸银、硝酸银、酒石酸银为前驱体的无颗粒型银导电墨水的研究情况。此外，对墨水作喷墨打印时基板的选择和处理、墨水印制图案的微观组织结构调控及后处理方法、墨水的应用、以及对无颗粒型银导电墨水的前景进行了介绍。     

Illuminating Diverse Concomitant DNA Logic Gates and Concatenated Circuits with Hairpin DNA-Templated Silver Nanoclusters as Universal Dual-Output Generators

Exquisite administration of a new type of hairpin DNA-templated silver nanoclusters (H-AgNCs) as universal dual-output generators in DNA-based logic systems is reported. Diverse concomitant contrary logic gates (CCLGs) with opposite functions (YES^{^}NOT, OR^{^}NOR, INHIBIT^{^}IMPLICATION, XOR^{^}XNOR, and MAJORITY^{^}MINORITY) and extended concatenated logic circuits are presented and some of them perform specific functions, such as parity generators and checkers. The introduction of H-AgNCs as noncovalent signal reporters avoids tedious and high-cost labeling procedures. Of note, the concomitant feature of CCLGs attributed to the dual-emitter AgNCs conduces to reducing the time and cost to devise multiple logic gates. As compared to previous ones, this design eliminates numerous substances (e.g., organic dyes) and unstable components (hydrogen peroxide), which not only decreases the complexity of logic performs and improves repeatability of operation, but also makes it convenient to connect distinct DNA-based logic gates. It is worthy to anticipate that the cost-effective strategy will inspire researchers to develop much more complex logic systems and contribute to the field of molecular computing.