Recent advances on bioreceptors and metal nanomaterials——based electrochemical impedance spectroscopy biosensors

Metal-based nanomaterials have a wide range of applications in energy conversion,catalysis,bioimaging,and sensors.In our review,we mainly introduce metal nanomaterials-based electrochemical impedance spectroscopy(EIS)biosensors in medical healthcare,environmental monitoring,and food safety instructively,with collecting and analyzing the current achievement of predecessors.In general,metal nanomaterials-based EIS biosensors can be divided into four components,in which bioreceptors and metal nanomaterials transducers are vital for designs.Bioreceptors and metal nanomaterials determine the feasibility,specificity,sensitivity and simplicity of manufacturing and operations.With the demonstration and discussion of bioreceptors and metal nanomaterials of biosensors in different fields,our review aims to assist brief acknowledgement of current state-of-the-art achievement and provide our insights for the future development.

Recent progress in structural modulation of metal nanomaterials for electrocatalytic CO_(2) reduction

The electrochemical CO_(2) reduction(ECR)into value-added products presents an appealing approach to mitigate CO_(2) emission caused by excess consumption of fossil fuels.To obtain high catalytic activity and selectivity toward target product in ECR,designing and developing a stable and efficient electrocatalyst is of significant importance.To date,metal nanomaterials have been widely applied as electrocatalysts for ECR due to their unique physicochemical properties.The structural modulation of metal nanomaterials is an attractive strategy to improve the catalytic performance.In this review,the recent progress of structural modulation,including size,facet,grain boundary,composition,interface,ligand modification,and crystal phase,is systematically summarized from both theoretical and experimental aspects.Finally,the opportunities and perspectives of structural modulation of metal nanomaterials for ECR are proposed.

Nanosurface chemistry and dose govern the bioaccumulation and toxicity of carbon nanotubes, metal nanomaterials and quantum dots in vivo

The chemical and biological mechanisms of life processes mostly consist of multistep and programmed processes at nanoscale levels. Interestingly enough, cell, the basic functional unit and platform that maintains life processes, is composed of various organelles fulfilling sophisticated functions through the precise control on the biomolecules （e.g., proteins, phospholipid, nucleic acid and ions） in a spatial dimension of nanoscale sizes. Thus, understanding of the activities of manufactured nanoscale materials including their interaction with biological sys- tems is of great significance in chemistry, materials sci- ence, life science, medicine, environmental science and toxicology. In this brief review, we summarized the recent advances in nanotoxicological chemistry through the dis- section of pivotal factors （primarily focusing on dose and nanosurface chemistry） in determining nanomaterial- induced biological/toxic responses with particular empha- sis on the nanomaterial bioaccumulation （and interaction organs or target organs） at intact animal level. Due to the volume of manufacture and material application, we deliberately discussed carbon nanotubes, metal/metal oxide nanomaterials and quantum dots, severing as representativematerial types to illustrate the impact of dose and nanosurface chemistry in these toxicological scenarios. Finally, we have also delineated the grand challenges in this field in a conceptual framework of nanotoxicological chemistry. It is noted that this review is a part of our persistent endeavor of building the systematic knowledge framework for toxicological properties of engineered nanomaterials.

Utilization of Nanomaterials as Anode Modifiers for Improving Microbial Fuel Cells Performance

Microbial fuel cells(MFCs)are an attractive innovation at the nexus of energy and water security for the future.MFC utilizes electrochemically active microorganisms to oxidize biodegradable substrates and generate bioelectricity in a single step.The material of the anode plays a vital role in increasing the MFC’s power output.The anode in MFC can be upgraded using nanomaterials providing benefits of exceptional physicochemical properties.The nanomaterials in anode gives a high surface area,improved electron transfer promotes electroactive biofilm.Enhanced power output in terms of Direct current(DC)can be obtained as the consequence of improved microbe-electrode interaction.However,several limitations like complex synthesis and degeneration of property do exist in the development of nanomaterial-based anode.The present review discusses different renewable nanomaterial applied in the anode to recover bioelectricity in MFC.Carbon nanomaterials have emerged in the past decade as promising materials for anode construction.Composite materials have also demonstrated the capacity to become potential anode materials of choice.Application of a few transition metal oxides have been explored for efficient extracellular electron transport(EET)from microbes to the anode.

Two-dimensional metal oxide nanosheets for rechargeable batteries

Two-dimensional（2D） metal oxide nanosheets have attracted much attention as potential electrode materials for rechargeable batteries in recent years. This is primarily due to their natural abundance, environmental compatibility, and low cost as well as good electrochemical properties. Despite the fact that most metal oxides possess low conductivity, the introduction of some conductive heterogeneous components, such as nano-carbon, carbon nanotubes（CNTs）, and graphene, to form metal oxide-based hybrids,can effectively overcome this drawback. In this mini review, we will summarize the recent advances of three typical 2D metal oxide nanomaterials, namely, binary metal oxides, ternary metal oxides, and hybrid metal oxides, which are used for the electrochemical applications of next-generation rechargeable batteries, mainly for lithium-ion batteries（LIBs） and sodium-ion batteries（SIBs）. Hence, this review intends to functionalize as a good reference for the further research on 2D nanomaterials and the further development of energy-storage devices.

Exploring biomedical applications with silver and copper nanotechnology

The overuse and misuse of antibiotics has accelerated the emergence of bacterial resistance,making the treatment of common infections increasingly difficult and challenging.This has led to a rise in infection rates,worsened patient outcomes,and heightened mortality risks.In response,researchers have been exploring new antimicrobial strategies,with metal nanomaterials of controllable shape and size gaining significant attention for their unique antibacterial properties.Among these,silver(Ag)and copper(Cu)nanomaterials(NMs)stand out for their wide applications in biomedical materials due to their effective antimicrobial mecha-nisms when used as drugs.Ag and Cu NMs,exemplifying metal biomaterials,showcase broad-spectrum antibacterial capabilities,durable antimicrobial effects,low toxicity,and reduced likelihood of developing drug resistance.Moreover,they are known to promote angiogenesis,making them exceptionally suitable for biomaterial applications.This review underscores the significance of Ag and Cu NMs in the biomedical sector,detailing their applications and the promising role they play as medical materials.Our aim is to encourage further exploration and utilization of Ag and Cu NMs in biomaterials and industrial production sectors.

Printable inorganic nanomaterials for flexible transparent electrodes:from synthesis to application

Printed and flexible electronics are definitely promising cutting-edge electronic technologies of the future. They offer a wide-variety of applications such as flexible circuits, flexible displays, flexible solar cells, skinlike pressure sensors, and radio frequency identification tags in our daily life. As the most-fundamental component of electronics, electrodes are made of conductive materials that play a key role in flexible and printed electronic devices. In this review, various inorganic conductive materials and strategies for obtaining highly conductive and uniform electrodes are demonstrated. Applications of printed electrodes fabricated via these strategies are also described. Nevertheless, there are a number of challenges yet to overcome to optimize the processing and performance of printed electrodes.

Phase engineering two-dimensional nanostructures for electrocatalytic hydrogen evolution reaction

Hydrogen(H2)is considered to be a promising substitute for fossil fuels.Two-dimensional(2D)nanomaterials have exhibited an efficient electrocatalytic capacity to catalyze hydrogen evolution reaction(HER).Particularly,phase engineering of 2D nanomaterials is opening a novel research direction to endow 2D nanostructures with fascinating properties for deep applications in catalyzing HER.In this review,we briefly summarize the research progress and present the current challenges on phase engineering of 2D nanomaterials for their applications in electrocatalytic HER.Our summary will be of significance to provide fundamental understanding for designing novel 2D nanomaterials with unconventional phases to electrochemically catalyze HER.

Facile synthesis of hierarchical flower-like Ag/Cu2O and Au/Cu2O nanostructures and enhanced catalytic performance in electrochemical reduction of CO2

Novel,hierarchical,flower-like Ag/Cu2O and Au/Cu2O nanostructures were successfully fabricated and applied as efficient electrocatalysts for the electrochemical reduction of CO2.Cu2O nanospheres with a uniform size of^180 nm were initially synthesized.Thereafter,Cu2O was used as a sacrificial template to prepare a series of Ag/Cu2O composites through galvanic replacement.By varying the Ag/Cu atomic ratio,Ago.12/Cu2O,having a hierarchical,flower-like nanostructure with intersecting Ag nanoflakes encompassing an inner Cu2O sphere,was prepared.The as-prepared Ag/Cu2O samples presented higher Faradaic efficiencies(FE)for CO and relatively suppressed H2 evolution than the parent Cu2O nanospheres due to the combination of Ag with Cu2O in the former.Notably,the highest CO evolution rate was achieved with Ago.12/Cu2O due to the larger electroactive surface area furnished by the hierarchical structure.The same hier-archical flower-like structure was also obtained for the Auo./Cu2O composite,where the FEco(10%)was even higher than that of Ago.12/Cu2O.Importantly,the results reveal that Ago.12/Cu2O and Auo./Cu2O both exhibit remarkably improved stability relative to Cu2O.This study presents a facile method of developing hierarchical metal-oxide composites as fficient and stable electrocatalysts for the electrochemical reduction of CO2.