Laser-Induced Graphene Hybrid Catalysts for Rechargeable Zn-Air Batteries

Rechargeable Zn-air batteries are projected to afford electrical energy storage with high energy and power density, safety, and economic viability. One of the key components in designing the battery is the cathode catalyst that is used to facilitate the cathodic reactions, specifically oxygen reduction and oxygen evolution reactions (ORR and OER). Here we report the facile synthesis of ternary metal oxide/graphene hybrid catalysts by combining ORR-active Co/Mn with OER-active Ni and Fe species to promote the bifunctional activity all in an in situ formed laser-induced graphene flexible film. These hybrid catalysts exhibit high catalytic activity and surpass the performance of precious metal Pt and RuO2 catalysts in Zn-air batteries. The batteries show high discharge peak power density of 98.9 mW cm–2 and energy density of 842 Wh kgZn–1. The batteries also show high reversibility and durability through charge/discharge cycles for >200 h. The catalysts demonstrate that applications in flexible Zn-air batteries that would be beneficial for wearable and flexible electronic devices

Laser-Induced Graphene Hybrid Catalysts for Rechargeable Zn-Air Batteries

Rechargeable Zn-air batteries are projected to afford electrical energy storage with high energy and power density, safety, and economic viability. One of the key components in designing the battery is the cathode catalyst that is used to facilitate the cathodic reactions, specifically oxygen reduction and oxygen evolution reactions (ORR and OER). Here we report the facile synthesis of ternary metal oxide/graphene hybrid catalysts by combining ORR-active Co/Mn with OER-active Ni and Fe species to promote the bifunctional activity all in an in situ formed laser-induced graphene flexible film. These hybrid catalysts exhibit high catalytic activity and surpass the performance of precious metal Pt and RuO2 catalysts in Zn-air batteries. The batteries show high discharge peak power density of 98.9 mW cm–2 and energy density of 842 Wh kgZn–1. The batteries also show high reversibility and durability through charge/discharge cycles for >200 h. The catalysts demonstrate that applications in flexible Zn-air batteries that would be beneficial for wearable and flexible electronic devices

Laser-Induced Graphene Hybrid Catalysts for Rechargeable Zn-Air Batteries

Rechargeable Zn-air batteries are projected to afford electrical energy storage with high energy and power density, safety, and economic viability. One of the key components in designing the battery is the cathode catalyst that is used to facilitate the cathodic reactions, specifically oxygen reduction and oxygen evolution reactions (ORR and OER). Here we report the facile synthesis of ternary metal oxide/graphene hybrid catalysts by combining ORR-active Co/Mn with OER-active Ni and Fe species to promote the bifunctional activity all in an in situ formed laser-induced graphene flexible film. These hybrid catalysts exhibit high catalytic activity and surpass the performance of precious metal Pt and RuO2 catalysts in Zn-air batteries. The batteries show high discharge peak power density of 98.9 mW cm–2 and energy density of 842 Wh kgZn–1. The batteries also show high reversibility and durability through charge/discharge cycles for >200 h. The catalysts demonstrate that applications in flexible Zn-air batteries that would be beneficial for wearable and flexible electronic devices

In Situ Synthesis of Efficient Water Oxidation Catalysts in Laser-Induced Graphene

NiFe-based catalysts are highly active for the oxygen evolution reaction (OER) in alkaline electrolytes. These catalysts are generally synthesized by solution-based methods. We present an in situ synthesis method for NiFe-based OER catalysts through a laser-induced graphene (LIG)-assisted process. By loading the metal precursor on a preformed LIG surface followed by laser scribing, we synthesized the NiFe/LIG catalysts via a solid phase transition that did not require utilization of CVD or typical solution-based reactions. The catalysts showed high OER activity and durability. The overpotential at 10 mA cm^–2 is as low as 240 mV with a Tafel slope of 32.8 mV dec^–1 in 1 M KOH. Additionally, this method worked well on a carbon fiber paper substrate, providing a convenient approach for the preparation of a free-standing catalytic electrode. This method provides a potential route to the facile synthesis of a variety of catalysts on a conductive surface

Oligo(phenothiazine)s: Twisted Intramolecular Charge Transfer and Aggregation-Induced Emission

Two 9,10-divinylanthracene oligomers containing phenothiazines (AnPHZ2 and AnPHZ4) are synthesized, and their intramolecular charge transfer as well as aggregation-induced emission (AIE) properties are investigated. Both oligomers show typical AIE properties as well as solvent polarity dependent emission. Time-resolved fluorescence spectra revealed that the twisted intramolecular charge transfer state formed in polar solvents accounts for the weak emission with large Stokes shifts, and the interactions between solvent and solutes facilitate the nonradiative decay. The restriction of intramolecular torsion induced by supramolecular interactions in aggregates eliminates the charge transfer state, thus resulting in efficient AIE

Table_1_Effects of agronomic traits and climatic factors on yield and yield stability of summer maize (Zea mays L) in the Huang-Huai-Hai Plain in China.docx

Zhengdan 958 (ZD958) is the summer maize variety with the widest planting area in Huang-Huai-Hai plain in the past 20 years. Understanding the agronomic characteristics of maize and its adaptability to climatic factors is of great significance for breeding maize varieties with high yield and stability. In this study, the experimental data of 33 experimental stations from 2005 to 2015 were analyzed to clarify the effects of different agronomic traits on yield and the correlation between agronomic traits, and to understand the effects of different climatic factors on summer maize yield and agronomic traits. The results showed that the average yield of ZD958 was 9.20 t ha-1, and the yield variation coefficient was 13.41%. There was a certainly negative correlation between high yield and high stability. Plant heights, ear heights, double ear rate, ear length, ear rows, line grain number, grain number per ear, ear diameter, cob diameter, and 1000 grains weight were significantly positive correlation with maize yield. Solar radiation before and after silking were significantly positive correlation with maize yield. Path analysis showed that changes in agronomic traits accounted for 54% of the yield variation, and changes in climate factors accounted for 26% of the yield variation. Our study showed that higher plant height, ear height, grain number per ear and 1000-grain weight, lower lodging rate, pour the discount rate and shorter bald tip long were the main reasons for high yield. Among the climatic factors, solar radiation and the lowest temperature have significant effects on the yield.</p

Tuning Metal Elements in Open Frameworks for Efficient Oxygen Evolution and Oxygen Reduction Reaction Catalysts

Electrochemical methods are promising technical routes for future clean energy storage and conversion. Most of the electrochemical methods involve oxygen reactions. Unfavorable kinetics and sluggish reactions are the main challenges for these processes. We report here a facile synthesis of highly efficient oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalysts. The catalysts are synthesized through the fine-tuning of metal ions (M, specifically Co, Ni, Zn, and Cu) in Prussian blue analogues (PBAs) and thus termed as M-PBAs. The CoNi-PBA-2 catalyst shows the highest activity toward OER with an onset potential at 280 mV and a Tafel slope of 63 mV dec–1. Zn-PBA catalysts demonstrate high selectivity in two-electron-transfer ORR. The H2O2 yield is as high as 88% at 0 V vs RHE. Density functional theory (DFT) calculations also confirm the high selectivity of Zn-PBA toward H2O2 in ORR

Convenient Synthesis of NiCo Alloy Nanoparticles Encapsulated by N‑Doped Porous Carbon for the Oxygen Evolution Reaction

Extremely important for water electrolysis are the rational design and investigation of oxygen evolution reaction (OER) electrocatalysts with excellent performance and long-term durability and that are precious metal-free. Herein, we demonstrate the convenient synthesis of a nitrogen-doped carbon-wrapped nickel cobalt alloy (NiCo2@NC) by pyrolysis of the metal complex. The results indicate that the ideal Ni/Co ratio and NC wrapping can provide high Cdl, low charge transfer resistance, and long-term durability for electrocatalysts, which are all reasons for significant OER performance. The optimal NiCo2@NC composite exhibits rapid OER reaction kinetics, which require a comparatively low overpotential of 288 mV at 10 mA cm–2 and a relatively small Tafel slope of 66 mV dec–1 in the alkaline electrolyte. Furthermore, I–t experiments were performed to demonstrate its better long-term catalytic endurance. In short, this study may provide guidance for the rational construction and design of carbon-coated bimetallic alloy materials

Effects of Liquid Environments on the Distribution of Hafnium Oxide and Hafnium Carbide Nanoparticles from Pulsed-Laser Synthesis: Implications for High-Melting Ceramics

Laser ablation in liquids (LAL) is an emerging laser technique for rapidly producing surfactant-free nanoparticles (NPs), which require minimal postprocessing and purification. Current work employing LAL has primarily focused on the generation of metal oxides and NPs composed of a single element. Here, we show that the ablation of hafnium (Hf) foil in different organic liquids allows for the controlled synthesis of HfO2 and HfC in selected ratios, resulting in a synthetic scheme for the rational design of materials relevant for high temperature and plasma applications. Additionally, the physical properties of the organic solvents can dictate the overall NP size distribution; specifically, solvents with low boiling points produce a large dispersity of NPs. This work indicates that the material-formation process is much more complicated than previous studies have indicated and paves the way for a pulsed-laser synthesis methodology that is tunable for desired properties

Video_1_The Third Hand of Neurosurgeons – a novel intraoperative malleable adjustable continuous suction tube.MP4

ObjectiveWe designed a novel intraoperative malleable adjustable continuous suction tube to obtain clear surgical fields, reduce intracranial pressure, and lower the temperature of the surgical area.MethodsThis device consists of six parts: continuous suction tube head and cotton patty, suction tube, fixed wire position, fixed clip, spiral plastic pressure regulating valve, and tail. It can continuously extract blood, cerebrospinal fluid, and rinsing solution from surgical fields, with minimal contact and trauma to tissues, nerves, and blood vessels, while also having a negligible impact on the surgeon’s focus and procedure.ResultThe excellent and safe performance (simple, malleable, adjustable, space-saving, inexpensive, safe, and effective) of this device in clearing the operating field has been proven in more than 2000 neurosurgical operative procedures. We encountered no complications associated with this device, such as cerebral hematoma, postoperative low intracranial pressure, or vascular and nerve injuries.ConclusionThe newly innovated intraoperative malleable adjustable continuous suction tube is effective and safe for microneurosurgery.</p