Nanoparticles of Pt/HxMoO3 electrodeposited in poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) as the electrocatalyst for methanol oxidation

Nanoparticles of platinum and hydrous molybdenum oxide (Pt/H_xMoO₃) were successfully electrodeposited onto poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT-PSS) film by chronocoulometry (0.2 C). Various loadings of Pt/H_xMoO₃ particles onto the PEDOT-PSS electrode were achieved using the co-deposition technique. The existence of Pt/H_xMoO₃ particles was determined through characterization by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis. XPS results revealed that deposited Pt and molybdenum were metallic Pt and H_xMoO₃, respectively. XRD analysis showed a decrease of Pt crystalline facets for the incorporation of H_xMoO₃ into PEDOT-PSS-Pt, indicating a strong interaction between Pt and H_xMoO₃. Scanning electron microscopy (SEM) results revealed a uniform dispersion of Pt/H_xMoO₃ particles, with the particle size of 70–90 nm, in the PEDOT-PSS matrix. The cyclic voltammetry study and chronopotentiometry measurements demonstrated that the PEDOT-PSS-Pt/H_xMoO₃ electrode had superior electrocatalytic activity of methanol oxidation with less CO poisoning. The presence of amorphous H_xMoO₃ particles on the Pt surface minimized CO poisoning of methanol oxidation.     

Logistic Regression with Elliptical Curve Cryptography to Establish Secure IoT

Nowadays, Wireless Sensor Network (WSN) is a modern technology with a wide range of applications and greatly attractive benefits, for example, self-governing, low expenditure on execution and data communication, long-term function, and unsupervised access to the network. The Internet of Things (IoT) is an attractive, exciting paradigm. By applying communication technologies in sensors and supervising features, WSNs have initiated communication between the IoT devices. Though IoT offers access to the highest amount of information collected through WSNs, it leads to privacy management problems. Hence, this paper provides a Logistic Regression machine learning with the Elliptical Curve Cryptography technique (LRECC) to establish a secure IoT structure for preventing, detecting, and mitigating threats. This approach uses the Elliptical Curve Cryptography (ECC) algorithm to generate and distribute security keys. ECC algorithm is a light weight key; thus, it minimizes the routing overhead. Furthermore, the Logistic Regression machine learning technique selects the transmitter based on intelligent results. The main application of this approach is smart cities. This approach provides continuing reliable routing paths with small overheads. In addition, route nodes cooperate with IoT, and it handles the resources proficiently and minimizes the 29.95% delay.     

Electrical and Electrochemical Characteristics of Withania somnifera Leaf Extract Incorporation Sodium Alginate Polymer Film for Energy Storage Applications

The current investigation addresses the alternating current electrical properties, electrochemical characteristics on biopolymer as Withania somnifera leaf extract incorporated sodium alginate [WLISA] polymer film prepared by solution casting method. Some crystallinity along with the amorphous nature of sodium alginate emerged due to the incorporation of Withania somnifera leaf extract [WSLE]. Two absorption maximum (λ_max) were obtained for both WLISA and WSLE samples in the UV–Vis spectrum. The blue, green, and red emission of WSLE and weak blue emission of WLISA are studied by PL analysis. The more amount of strain that occurred in crystallization provides broaden peak in X-ray diffraction pattern. With aid of guluronic and mannuronic acids in sodium alginate making hydroxyl bond formation with leaf extract due to the cross-linking process can be analyzed from Fourier transform infrared spectroscopy. The EDAX analysis showed the chemical composition of WSLE. At room temperature, the prepared 5 ml leaf extract WLISA film has demonstrated the highest ionic conductivity in the typical value of 2.80?×?10^–6 S/Cm. The electrochemical window of the prepared polymer film is in the range of ? 0.4 to 0.4 V suggesting that used as an electrolyte for supercapacitor applications.

     

Precision Nanocluster-Based Toroidal and Supertoroidal Frameworks Using Photocycloaddition-Assisted Dynamic Covalent Chemistry

Atomically precise nanoclusters (NCs) have recently emerged as ideal building blocks for constructing self-assembled multifunctional superstructures. The existing structures are based on various non-covalent interactions of the ligands on the NC surface, resulting in inter-NC interactions. Despite recent demonstrations on light-induced reversible self-assembly, long-range reversible self-assembly based on dynamic covalent chemistry on the NC surface has yet to be investigated. Here, it is shown that Au₂₅ NCs containing thiolated umbelliferone (7-hydroxycoumarin) ligands allow [2+2] photocycloaddition reaction-induced self-assembly into colloidal-level toroids. The toroids upon further irradiation undergo inter-toroidal reaction resulting in macroscopic supertoroidal honey-comb frameworks. Systematic investigation using electron microscopy, atomic force microscopy (AFM), and electron tomography (ET) suggest that the NCs initially form spherical aggregates. The spherical structures further undergo fusion resulting in toroid formation. Finally, the toroids fuse into macroscopic honeycomb frameworks. As a proof-of-concept, a cross-photocycloaddition reaction between coumarin-tethered NCs and an anticancer drug (5-fluorouracil) is demonstrated as a model photo-controlled drug release system. The model system allows systematic loading and unloading of the drug during the assembly and disassembly under two different wavelengths. The results suggest that the dynamic covalent chemistry on the NC surface offers a facile route for hierarchical multifunctional frameworks and photocontrolled drug release.