This paper investigates the pseudospectra and the numerical range of the OrrSommerfeld operator for plane Poiseuille flow. A number z E C is in the E-pseudospectrum of a matrix or operator A if Il(zI A)-'II 2 E-l, or, equivalently, if z is in the spectrum of A + E for some perturbation E satisfying IlEll 5 E. The numerical range of A is the set of numbers of the form (Au, u), where (., .) is th...

A general solvent-dependent protocol directly influencing the oxygen reduction reaction (ORR) in metal oxide/graphene nanohybrids has been demonstrated. We conducted the two-step synthesis of cobalt oxide/N-doped graphene nanohybrids (CNG) with solvents of water, ethanol, and dimethylformamide (DMF), representing tree typical categories of aqueous, polar organic, and organic N-containing solven...

3D and porous reduced graphene oxide (rGO) catalysts have been prepared with sp3-hybridized 1,4-diaminobutane (sp3-DABu, rGO-sp3-rGO) and sp2-hybridized 1,4-diaminobenzene (sp2-DABe, rGO-sp2-rGO) through a covalent amidation and have employed as a metal-free electrocatalyst for oxygen reduction reaction (ORR) in alkaline media. Both compounds have used as a junction between functionalized rGO l...

Synthesis of boron-carbon-nitrogen (BCN) nanocarbon with a controllable bond structure for enhanced oxygen reduction reaction (ORR) activity and durability was performed using a new method of discharge in organic solution mixtures named the 'Solution Plasma Process'. Using selected precursors a new strategy for the simultaneous synthesis of nanocarbon co-doped with heteroatoms was found. The sy...

Reduced graphene oxide (rGO), as a newly emerged carbon material, has attracted great attention concerning its applications for electrocatalysts. Presently, there are mixed opinions regarding the advantages to using rGO as a support for preparing nonprecious metal catalysts for the oxygen reduction reaction (ORR). The primary goal of this work is to determine whether rGO would be favorable for ...

In this study PtFeCo ternary alloys nanoparticles of three dimentional (3D) rhombus shapes dispersed on graphene nanosheets (PtFeCo/Gr) were successfully prepared and studied as electrocatalysts for oxygen reduction reaction (ORR) in polymer-electrolyte fuel cells. A combination of analytical techniques including powder X-ray diffraction, X-ray photoelectron spectra, inductively coupled plasma-...

Due to the limited reaction rate of oxygen reduction (ORR), it is considered as a limiting factor in performance fuel cells and metal-air batteries. Platinum benchmark catalyst for ORR; however, scarcity platinum, its high price, drift phenomenon, insufficient durability, susceptibility gas poisoning are reasons constant search new ORR catalysts. Carbon-based catalysts show exceptional promise ...

Microbial fuel cells (MFCs) are a promising green approach for wastewater treatment with the simultaneous advantage of energy production. Among the various limiting factors, the cathodic limitation, with respect to performance and cost, is one of the main obstacles to the practical applications of MFCs. Despite the high performance of platinum and other metal-based cathodes, their practical use...

Non–noble metal catalysts have recently emerged as promising alternatives to the expensive platinum catalysts for the oxygen reduction reaction (ORR). In this study, a new domain of materials, copper based coordination polymers, has been investigated as promising catalysts for ORR. The study was inspired by copper incorporating biomolecules, which efficiently catalyse the oxygen reduction react...