Showing papers on "Nanocomposite published in 2022"

Multifunctional Wearable Silver Nanowire Decorated Leather Nanocomposites for Joule Heating, Electromagnetic Interference Shielding and Piezoresistive Sensing

Abstract: Multifunctional wearable electronic devices based on natural materials are highly desirable for versatile applications of energy conversion, electronic skin and artificial intelligence. Herein, multifunctional wearable silver nanowire decorated leather (AgNW/leather) nanocomposites with hierarchical structures for integrated visual Joule heating, electromagnetic interference (EMI) shielding and piezoresistive sensing are fabricated via the facile vacuum-assisted filtration process. The AgNWs penetrate the micro-nano porous structures in the corium side of leather constructing highly-efficient conductive networks. The resultant flexible and mechanically strong AgNW/leather nanocomposites exhibit extremely low sheet resistance of 0.8 Ω/sq, superior visual Joule heating temperatures up to 108°C at low supplied voltage of 2.0 V due to efficient energy conversion, excellent EMI shielding effectiveness (EMI SE) of ~55 dB and outstanding piezoresistive sensing ability in human motion detection. This work demonstrates the fabrication of multifunctional AgNW/leather nanocomposites for next-generation wearable electronic devices in energy conversion, electronic skin and artificial intelligence, etc .

Multiscale engineered artificial tooth enamel

Abstract: Tooth enamel, renowned for its high stiffness, hardness, and viscoelasticity, is an ideal model for designing biomimetic materials, but accurate replication of complex hierarchical organization of high-performance biomaterials in scalable abiological composites is challenging. We engineered an enamel analog with the essential hierarchical structure at multiple scales through assembly of amorphous intergranular phase (AIP)–coated hydroxyapatite nanowires intertwined with polyvinyl alcohol. The nanocomposite simultaneously exhibited high stiffness, hardness, strength, viscoelasticity, and toughness, exceeding the properties of enamel and previously manufactured bulk enamel-inspired materials. The presence of AIP, polymer confinement, and strong interfacial adhesion are all needed for high mechanical performance. This multiscale design is suitable for scalable production of high-performance materials. Description Artificial enamel analog Tooth enamel is the thin outer layer of our teeth and is the hardest biological material in the human body. Zhao et al. engineered an enamel analog consisting of assembled hydroxyapatite nanowires with amorphous intergranular phase segments aligned using scalable, dual-directional freezing in the presence of polyvinyl alcohol. The artificial tooth enamel was designed to closely mimic the composition of the natural material by copying the shapes and sizes of the components found biologically and the organization of their interfaces. —MSL A stiff, hard, strong, tough artificial enamel analog was self-assembled from nanowires with amorphous intergranular phase segments.

Graphene composites with Ru-RuO2 heterostructures: Highly efficient Mott–Schottky-type electrocatalysts for pH-universal water splitting and flexible zinc–air batteries

Abstract: Development of high-efficiency electrocatalysts for pH-universal overall water splitting is a critical step towards a sustainable hydrogen economy. Herein, graphene nanocomposites with Ru-RuO2 Mott-Schottky heterojunctions (Ru-RuO2@NPC) are prepared pyrolytically and exhibit a remarkable electrocatalytic activity at pH = 0–14 towards both oxygen/hydrogen evolution reactions and overall water splitting, as compared to commercial RuO2 and Pt/C. Ru-RuO2@NPC can also be used as an effective air cathode catalyst for flexible, rechargeable zinc-air batteries. Density functional theory calculations show that the formation of Ru-RuO2 heterojunctions moderately enhances the surface charge density of metallic Ru and brings the d states closer to Fermi level, as compared to that of RuO2 alone, leading to improved intrinsic electrocatalytic activity towards these important reactions. These results demonstrate the significance of Mott-Schottky heterojunctions in the development of high-efficiency electrocatalysts for various new energy technologies.

Graphene composites with Ru-RuO2 heterostructures: Highly efficient Mott–Schottky-type electrocatalysts for pH-universal water splitting and flexible zinc–air batteries

Abstract: Development of high-efficiency electrocatalysts for pH-universal overall water splitting is a critical step towards a sustainable hydrogen economy. Herein, graphene nanocomposites with Ru-RuO2 Mott-Schottky heterojunctions (Ru-RuO2@NPC) are prepared pyrolytically and exhibit a remarkable electrocatalytic activity at pH = 0–14 towards both oxygen/hydrogen evolution reactions and overall water splitting, as compared to commercial RuO2 and Pt/C. Ru-RuO2@NPC can also be used as an effective air cathode catalyst for flexible, rechargeable zinc-air batteries. Density functional theory calculations show that the formation of Ru-RuO2 heterojunctions moderately enhances the surface charge density of metallic Ru and brings the d states closer to Fermi level, as compared to that of RuO2 alone, leading to improved intrinsic electrocatalytic activity towards these important reactions. These results demonstrate the significance of Mott-Schottky heterojunctions in the development of high-efficiency electrocatalysts for various new energy technologies.

Magnetic NiFe2O4/Polypyrrole nanocomposites with enhanced electromagnetic wave absorption

Abstract: NiFe2O4/polypyrrole (NiFe2O4/PPy) nanocomposites are prepared by a simple surface-initiated polymerization method and demonstrate negative permittivity in the low frequency regions. These nanocomposites also exhibit significantly enhanced electromagnetic wave (EMW) absorption property in the high frequency regions. Compared with pure PPy, the enhanced negative permittivity is observed in the NiFe2O4/PPy nanocomposites with a NiFe2O4 loading of 5.0, 10.0, 20.0 and 40.0 wt%, indicating the formation of metal-like electrical conducting network in NiFe2O4/PPy nanocomposites. Moreover, the negative permittivity could be tuned by changing the NiFe2O4 loading. The minimum reflection loss (RL) of -40.8 dB is observed in the 40.0 wt% NiFe2O4/PPy composites with a thickness of only 1.9 mm. The effective absorption bandwidth below -10.0 and -20.0 dB reaches 6.08 and 2.08 GHz, respectively. The enhanced EMW absorption performance benefits from the improved independence matching, EMW attenuation capacity, and synergistic effects of conduction loss, dielectric loss (interfacial and dipole polarizations) and magnetic loss (exchange and natural resonances). This research work provides a guidance for the fabrication of nanocomposites with an excellent EMW absorption.

Magnetic-MXene-based nanocomposites for water and wastewater treatment: A review

Abstract: An increase in the pollutants such as hazardous refractory contaminations, organic dyes, pharmaceutical and pesticide contaminants which are widely disposed to water resources due to population and global industrialization is becoming one of the most significant health issues in the world. Due to the unique properties, easy production, low-cost preparation, and excellent degradation of water and wastewater pollutants, magnetic-MXene nanocomposites are promising candidates with many attractive characteristics. These composites offer new fascinating perspectives in various applications such as biosensors, cancer theragnostic, imaging strategies, and especially in water treatment. This paper reviews magnetic-MXene nanocomposites for removing contaminants from aqueous environments. The concept of using magnetic nanomaterials for water treatment, MXene applications and implications for the degradation of water and wastewater pollutants, and magnetic-MXene nanocomposites for water treatment will be discussed. Future trends on MXene and Magnetic-MXene nanomaterials for water treatment and environmental applications will also be explained. • Pollutants removal by magnetic-MXene-based nanocomposites was reviewed. • Magnetization of nanocomposites of MXene enhanced pollutants degradation. • Magnetization of nanocomposites of MXene enhanced antibacterial properties. • A future perspective was developed.

A Comprehensive Review of Graphitic Carbon Nitride (g-C3N4)–Metal Oxide-Based Nanocomposites: Potential for Photocatalysis and Sensing

Abstract: g-C3N4 has drawn lots of attention due to its photocatalytic activity, low-cost and facile synthesis, and interesting layered structure. However, to improve some of the properties of g-C3N4, such as photochemical stability, electrical band structure, and to decrease charge recombination rate, and towards effective light-harvesting, g-C3N4–metal oxide-based heterojunctions have been introduced. In this review, we initially discussed the preparation, modification, and physical properties of the g-C3N4 and then, we discussed the combination of g-C3N4 with various metal oxides such as TiO2, ZnO, FeO, Fe2O3, Fe3O4, WO3, SnO, SnO2, etc. We summarized some of their characteristic properties of these heterojunctions, their optical features, photocatalytic performance, and electrical band edge positions. This review covers recent advances, including applications in water splitting, CO2 reduction, and photodegradation of organic pollutants, sensors, bacterial disinfection, and supercapacitors. We show that metal oxides can improve the efficiency of the bare g-C3N4 to make the composites suitable for a wide range of applications. Finally, this review provides some perspectives, limitations, and challenges in investigation of g-C3N4–metal-oxide-based heterojunctions.

A high-performance room temperature benzene gas sensor based on CoTiO3 covered TiO2 nanospheres decorated with Pd nanoparticles

Abstract: A benzene sensor based on Pd doped CoTiO3/TiO2 (Pd-CTT) nanocomposite was reported in this paper. The surface morphology and structure composition of the samples were investigated by SEM, TEM, XRD and XPS. The benzene sensing performance of the sensors with different ratios of CoTiO3 and TiO2 was studied at room temperature (RT) of 25 °C. The gas sensing performance of the sensor was further improved by the construction of Pd-CTT ternary composite sensing material. The results show that the sensor has remarkable sensing performance for benzene, including excellent linear response, rapid detection speed, good repeatability and stability. The Pd-CTT sensor showed a high response (Rg/Ra = 33.46 @ 50 ppm) to benzene, with detection limit as low as 100 ppb. The excellent benzene sensing properties of Pd-CTT sensor are attributed to the formation of CoTiO3/TiO2 p-n heterojunction and catalytic action of Pd. This work highlights the unique advantage of Pd-CTT nanocomposite for benzene sensor.

A high-performance room temperature benzene gas sensor based on CoTiO3 covered TiO2 nanospheres decorated with Pd nanoparticles

Abstract: A benzene sensor based on Pd doped CoTiO3/TiO2 (Pd-CTT) nanocomposite was reported in this paper. The surface morphology and structure composition of the samples were investigated by SEM, TEM, XRD and XPS. The benzene sensing performance of the sensors with different ratios of CoTiO3 and TiO2 was studied at room temperature (RT) of 25 °C. The gas sensing performance of the sensor was further improved by the construction of Pd-CTT ternary composite sensing material. The results show that the sensor has remarkable sensing performance for benzene, including excellent linear response, rapid detection speed, good repeatability and stability. The Pd-CTT sensor showed a high response (Rg/Ra = 33.46 @ 50 ppm) to benzene, with detection limit as low as 100 ppb. The excellent benzene sensing properties of Pd-CTT sensor are attributed to the formation of CoTiO3/TiO2 p-n heterojunction and catalytic action of Pd. This work highlights the unique advantage of Pd-CTT nanocomposite for benzene sensor.