Golden single-atomic-site platinum electrocatalysts

Bimetallic nanoparticles with tailored structures constitute a desirable model system for catalysts, as crucial factors such as geometric and electronic effects can be readily controlled by tailoring the structure and alloy bonding of the catalytic site. Here we report a facile colloidal method to prepare a series of platinum–gold (PtAu) nanoparticles with tailored surface structures and particle diameters on the order of 7 nm. Samples with low Pt content, particularly Pt 4 Au 96 , exhibited unprecedented electrocatalytic activity for the oxidation of formic acid. A high forward current density of 3.77 A mg Pt −1 was observed for Pt 4 Au 96 , a value two orders of magnitude greater than those observed for core–shell structured Pt 78 Au 22 and a commercial Pt nanocatalyst. Extensive structural characterization and theoretical density functional theory simulations of the best-performing catalysts revealed densely packed single-atom Pt surface sites surrounded by Au atoms, which suggests that their superior catalytic activity and selectivity could be attributed to the unique structural and alloy-bonding properties of these single-atomic-site catalysts

Design of XOR Photonic Gate using Highly Nonlinear Fiber

In this paper, a comprehensive design and simulation of an all-photonic XOR logic gate is proposed. The design is based on the third-order Kerr nonlinear effect in highly nonlinear fiber, i.e., utilizing the self-phase and cross-phase modulations phenomena. This work presents the first photonic logic gate based on highly nonlinear fiber component only that achieves a data rate of 20 Gbps. Moreover, the design is based on two input binary bit sequences, narrow pulsed by a Gaussian distribution as 8-bit incoming data streams. Also, optical cross connectors with different coupling coefficients are used to generate pump and probe signals and tuneable optical band pass filters are leveraged to perform the logic gate functionalities. Remarkable performance outcomes are concluded from the eye pattern diagram and bit error rate analyzers. Simulation results show that the proposed XOR optical logic gate design is achieved at very low power penalties, low bit error rates, a significant Q-factor, and high extinction ratios as compared to existing methods

Acta Musei Moraviae / Scientiae geologicae

The inkjet printing of CNTbiopolymer composite inks onto solid and gel substrates was investigated. Changing the substrate from glass to gel resulted in an increase in the resistance of printed materials from 9.85 kΩ/cm to 39.42 kΩ/cm

Synthesis of Metallocene Catalyzed Ethylene 1,7-Octadiene Copolymer: Effect of Copolymerization on Polymer Properties

In this article, metallocene catalyzed polyethylene homopolymer and ethylene 1,7-octadiene copolymers were synthesized and the produced polymers were characterized. The results show that these polymers were high density polyethylene. The effect of comonomer 1,7-octadiene on thermal, mechanical, and rheological properties of the polymers was investigated. The molecular weight, melting temperature (Tm), d-spacing, crystallite size, and % crystallinity (% Xc) decrease with the increase in comonomer content. Polyethylene homopolymer and copolymer exhibit cold drawing processes. The tensile stress-strain plots show multiple necks. A reduction in tensile modulus, strength, and strain at break is seen for copolymers compared to homopolymer. The effect of comonomer content on dynamic and extensional rheology of the polymers was also studied. In addition, Direct Current conductivity and dielectric property of the polymers were also reported. The results were interpreted in terms of mainly polymer type, molecular weight, and crystallinity. [Figure not available: see fulltext.]. - 2018, The Polymer Society of Korea and Springer Science+Business Media B.V., part of Springer Nature.Scopu

Fabrication and characterisation of sulfur and phosphorus (S/P) co-doped carbon nanotubes

Abstract not availableTariq Altalhi, Amine Mezni, Ali Aldalbahi, Arwa Alrooqi, Yasser Attia, Abel Santos, Dusan Losi

Size-and shape-controlled synthesis of well-organised carbon nanotubes using nanoporous anodic alumina with different pore diameters

Abstract not availableAmine Mezni, Tariq Altalhi, Nesrine Ben Saber, Ali Aldalbahi, Seifeddine Boulehmi, Abel Santos, Dusan Losi