Synthesis and Crystallization Studies of Thermo-plastic Polyster/Titania Nanocomposites

The present work reports the non-isothermal crystallization kinetics of PET-TiO2 nanocomposites. The average particle size of TiO2 nanoparticles, prepared by chemical route, has been calculated 32 nm using Debay-Scherrer’s formula in XRD peaks. PET-TiO2 nanocomposites have been synthesized using solution casting method. The investigation of non-isothermal crystallization behavior has been conducted by means of Differential Scanning Calorimeter (DSC). The crystallization temperature shift to lower temperature for both PET pristine and PET-TiO2 nanocomposites due to decrease in mobility of chain segments and heterogeneous nucleation. Also, the inclusion of TiO2 nanoparticles may accelerate nucleation rate in nanocomposites that causes the crystallization time and absolute crystallinity fraction. The thermal conductivity of inorganic filler TiO2 nanoparticles may affect the crystallization temperature

Nitrogen-doped carbon nano-onions/polypyrrole nanocomposite based low-cost flexible sensor for room temperature ammonia detection

Abstract One of the frontier research areas in the field of gas sensing is high-performance room temperature-based novel sensing materials, and new family of low-cost and eco-friendly carbon nanomaterials with a unique structure has attracted significant attention. In this work, we propose a novel low-cost flexible room temperature ammonia gas sensor based on nitrogen-doped carbon nano-onions/polypyrrole (NCNO-PPy) composite material mounted low-cost membrane substrate was synthesized by combining hydrothermal and in-situ chemical polymerization methods. The proposed flexible sensor revealed high sensing performance when employed as the sensing material for ammonia detection at room temperature. The NCNO-PPy ammonia sensor exhibited 17.32% response for 100 ppm ammonia concentration with a low response time of 26 s. The NCNO-PPy based flexible sensor displays high selectivity, good repeatability, and long-term durability with 1 ppm as the lower detection limit. The proposed flexible sensor also demonstrated remarkable mechanical robustness under extreme bending conditions, i.e., up to 90° bending angle and 500 bending cycles. This enhanced sensing performance can be related to the potential bonding and synergistic interaction between nitrogen-doped CNOs and PPy, the formation of defects from nitrogen doping, and the presence of high reactive sites on the surface of NCNO-PPy composites. Additionally, the computational study was performed on optimized NCNO-PPy nanocomposite for both with and without NH3 interaction. A deeper understanding of the sensing phenomena was proposed by the computation of several electronic characteristics, such as band gap, electron affinity, and ionization potential, for the optimized composite

An efficient one pot three-component nanocatalyzed synthesis of spiroheterocycles using TiO2 nanoparticles as a heterogeneous catalyst

An efficient and environmentally benign isocyanide based domino protocol has been presented for the synthesis of structurally diverse spiroheterocycles, spiroannulated with imidazothiazole and imidazothiadiazole, involving the three component reaction of 2-aminobenzothiazole/2-amino-1,3,4-thiadiazole, cyclohexyl/tert-butyl isocyanides and isatines/cyclic carbonyl compounds catalyzed by recyclable and reusable nanocrystalline TiO2

Facile synthesis of Pd@ZnO core@shell nanoparticles for selective ethanol detection

In this work, we reported a high-performance ethanol gas sensor based on novel Pd@ZnO core@shell nanoparticles (CSNPs). The Pd@ZnO CSNPs were synthesized by chemical method and characterized by XRD, TEM and EDS techniques. Gas sensing results demonstrated that Pd@ZnO CSNPs show high sensitivity and remarkable selectivity towards ethanol at 250 °C. The response value of Pd@ZnO CSNPs is 152, which is almost six times higher than the response value (27) of ZnO NPs at 250 °C. The mechanism of enhancement in sensing properties can be ascribed to the chemical and electronic sensitization effect of Pd NPs and also due to the unique core@shell structure. These characteristics may shed light on the development of a selective ethanol sensor based on Pd@ZnO CSNPs

Heteroatom Doping in Pollutant Diesel Soot-Derived Nanocarbon for Enhanced Zn-Ion Storage Performance

Herein, we have isolated onion-like nanocarbon (ONC) from the exhaust soot of diesel engines and further doped it with nitrogen (N) and sulfur (S) to fabricate N,S-co-doped ONC (N–S–ONC). To explore its application feasibility, we have assembled an aqueous Zn-ion hybrid supercapacitor (ZIHSC) with a N–S–ONC cathode, which attains high specific capacitance with good rate capability. In-depth analyses suggest that the mechanism of charge storage in the ONC is governed by both capacitive-controlled and diffusion-controlled processes, with the capacitive processes leading at all sweep rates. The ZIHSC demonstrated a good energy density of 50 Wh/kg, a maximum power density of 3.6 kW/kg, and an impressive cycle life with 73% capacitance retention after 50,000 charge–discharge cycles. The study suggests the potential possibly for the long-term application of BC derived nanocarbon in electrochemical energy storage systems (EESSs)