Bio-Assisted Atomically Dispersed Fe–N–C Electrocatalyst with Ultra-Low Fe Loading toward pH-Universal Oxygen Reduction Reaction and Neutral Zn-Air Battery

The advancement in the design of non-platinum noble metal-based oxygen reduction reaction (ORR) electrocatalysts with pH universality is crucial for the implementation of renewable energy devices in various environments. In this study, we present a convenient bio-assisted synthesis approach for the preparation of Fe–N–C catalysts, Fe@G-800/100. The Fe–N4 active sites, distributed atomically in the catalyst, confer remarkable ORR activity, leading to half-wave potentials (E1/2) of 0.91, 0.70, and 0.83 V vs RHE in alkaline, acidic, and neutral media, respectively. These values surpass the performance of state-of-the-art pH-universal ORR catalysts. We have also demonstrated the feasibility of constructing a cathode for a liquid Zn-air battery (ZAB) by utilizing Fe@G-800/100, with a rarely used PBS-derived neutral electrolyte. The resulting neutral ZAB exhibits a high open-circuit voltage, excellent charge–discharge cycling behavior, and significant specific capacity. Our findings provide valuable observations on the potential of pH-universal Fe–N–C catalysts and a roadmap for the design of neutral ZABs

Aptamer-based fluorometric determination of <i>Salmonella Typhimurium</i> using Fe₃O₄ magnetic separation and CdTe quantum dots - Fig 7

(a) Fluorescence spectra of aptasensors with different concentrations (from a to h: 1010, 107, 105, 104, 103, 102, 10, 0 cfu•mL-1) of S. Typhimurium; (b) calibration curve of the fluorescence intensity of the QDs@ssDNA2 at 612 nm for S. Typhimurium detection.</p

Aptamer-based fluorometric determination of <i>Salmonella Typhimurium</i> using Fe₃O₄ magnetic separation and CdTe quantum dots - Fig 3

TEM (a) and HRTEM (b) images of CdTe QDs.</p

Interface Engineering Based on Liquid Metal for Compact-Layer-free, Fully Printable Mesoscopic Perovskite Solar Cells

A printing process for the fabrication of perovskite solar cells (PSCs) exhibits promising future application in the photovoltaic industry due to its low-cost and eco-friendly preparation. In mesoscopic carbon-based PSCs, however, compared to conventional ones, the hole-transport-layer-free PSCs often lead to inefficient hole extraction. Here, we used liquid metal (LM, Galinstan) as an interface modifier material in combination with a carbon electrode. Considering the high conductivity and room-temperature fluidity, it is found that LMs are superior in improving hole extraction and, more importantly, LMs tend to be reserved at the interface between ZrO2 and carbon for enhancing the contact property. Correspondingly, the carrier transfer resistance was decreased at the carbon/perovskite interface. As optimized content, the triple mesoscopic PSCs based on mixed-cation perovskite with a power conversion efficiency of 13.51% was achieved, involving a 26% increase compared to those without LMs. This work opens new techniques for LMs in optoelectronics and printing

Unique and Excellent Paintable Liquid Metal for Fluorescent Displays

A liquid metal (LM) generally has excellent electrical conductivity, thermal conductivity, flexibility, fluidity, and reflectivity. Innovative electronics using a LM to paint colorful fluorescent patterns may be applied to many important fields. Herein we propose, for the first time, the use of a LM to paint fluorescent patterns in the field of natural science. An LM containing a main-group metal (Ga50.25Bi8.28In28.2Sn13.27) is used to paint a uniform alloy film on a ceramic substrate. The painting is not restricted by any curved surface, shape, or size, which therefore gives the LM diverse adaptability. We have adopted the strategy of “painting–annealing–dealloying” through which LM can easily be diffused and doped into the substrate to produce various defects. Defects, my themselves or through their interactions, can produce different colors of emitted light. The primary fluorescence colors, such as purple, yellow, blue, and white, have been painted with the LM. Importantly, the brightness and color coordinates can be adjusted by changing the LM composition or annealing temperature, and intricate, delicate, colorful fluorescence patterns can be produced. Due to the unique painting form, colorful fluorescence, high stability, corrosion resistance, and low cost of the technique used for the LM, it can be used for displays, lighting panels, flexible electronic circuits, anticounterfeiting devices, and sensors

Aptamer-based fluorometric determination of <i>Salmonella Typhimurium</i> using Fe₃O₄ magnetic separation and CdTe quantum dots - Fig 1

The flow chart diagram of synthesis of QDs (a), QDs-ssDNA2 (b) and aptamer@MNPs (c).</p

Unique and Excellent Paintable Liquid Metal for Fluorescent Displays

A liquid metal (LM) generally has excellent electrical conductivity, thermal conductivity, flexibility, fluidity, and reflectivity. Innovative electronics using a LM to paint colorful fluorescent patterns may be applied to many important fields. Herein we propose, for the first time, the use of a LM to paint fluorescent patterns in the field of natural science. An LM containing a main-group metal (Ga50.25Bi8.28In28.2Sn13.27) is used to paint a uniform alloy film on a ceramic substrate. The painting is not restricted by any curved surface, shape, or size, which therefore gives the LM diverse adaptability. We have adopted the strategy of “painting–annealing–dealloying” through which LM can easily be diffused and doped into the substrate to produce various defects. Defects, my themselves or through their interactions, can produce different colors of emitted light. The primary fluorescence colors, such as purple, yellow, blue, and white, have been painted with the LM. Importantly, the brightness and color coordinates can be adjusted by changing the LM composition or annealing temperature, and intricate, delicate, colorful fluorescence patterns can be produced. Due to the unique painting form, colorful fluorescence, high stability, corrosion resistance, and low cost of the technique used for the LM, it can be used for displays, lighting panels, flexible electronic circuits, anticounterfeiting devices, and sensors

Aptamer-based fluorometric determination of <i>Salmonella Typhimurium</i> using Fe₃O₄ magnetic separation and CdTe quantum dots - Fig 2

Schematic diagram of (a) the synthesis of streptavidin magnetic nanoparticles and carboxyl CdTe QDs, (b) illustration of the detection of S. Typhimurium.</p

Aptamer-based fluorometric determination of <i>Salmonella Typhimurium</i> using Fe₃O₄ magnetic separation and CdTe quantum dots - Fig 6

(a) UV-visible absorption spectrum of 10 μL of 1 mg•mL-1 streptavidin-coated MNPs decorated with 50 μL of 10 nM aptamer. (b) Fluorescence spectra of different concentrations (from 70 μL to 10 μL) of ssDNA2@CdTe QDs of 30 μg·mL-1 ssDNA2@CdTe QDs. (c) Fluorescence spectra of aptamer&QDs-ssDNA2@MNPs after different incubation times with S. Typhimurium. (d) Fluorescence spectra of aptamer&QDs-ssDNA2@MNPs incubated with S. Typhimurium at different incubation temperatures.</p

Unique and Excellent Paintable Liquid Metal for Fluorescent Displays

A liquid metal (LM) generally has excellent electrical conductivity, thermal conductivity, flexibility, fluidity, and reflectivity. Innovative electronics using a LM to paint colorful fluorescent patterns may be applied to many important fields. Herein we propose, for the first time, the use of a LM to paint fluorescent patterns in the field of natural science. An LM containing a main-group metal (Ga50.25Bi8.28In28.2Sn13.27) is used to paint a uniform alloy film on a ceramic substrate. The painting is not restricted by any curved surface, shape, or size, which therefore gives the LM diverse adaptability. We have adopted the strategy of “painting–annealing–dealloying” through which LM can easily be diffused and doped into the substrate to produce various defects. Defects, my themselves or through their interactions, can produce different colors of emitted light. The primary fluorescence colors, such as purple, yellow, blue, and white, have been painted with the LM. Importantly, the brightness and color coordinates can be adjusted by changing the LM composition or annealing temperature, and intricate, delicate, colorful fluorescence patterns can be produced. Due to the unique painting form, colorful fluorescence, high stability, corrosion resistance, and low cost of the technique used for the LM, it can be used for displays, lighting panels, flexible electronic circuits, anticounterfeiting devices, and sensors