Using impedance spectroscopy the electrical response of sensors with various porous Y-stabilized ZrO2 (YSZ) microstructures was measured for gas concentrations containing 0-100 ppm NO with 10.5%O2 at temperatures ranging from 600-700 °C. The impedance response increased substantially as the sensor porosity increased from 46%-50%. Activation energies calculated based on data from the impedance m...

The oxidation of CO has attracted great interest in recent years because of its important role in enhancing the catalyst durability in fuel cells and in solving the growing environmental problems caused by CO emission. The usually used noble metal nanocatalysts are costly and require high reaction temperature for efficient operation. We report here a density functional theory (DFT) study of low...

The chemical oxidation of activated carbon by H2 O2 and H2 SO4 is investigated, structural and chemical modifications are characterized, and the materials are used as catalysts for the hydrolysis of cellulose. Treatment with H2 O2 enlarges the pore size and imparts functional groups such as phenols, lactones, and carboxylic acids. H2 SO4 treatment targets the edges of carbon sheets primarily, a...

Large Li2O2 aggregations can produce high-capacity of lithium oxygen (Li-O2) batteries, but the larger ones usually lead to less-efficient contact between Li2O2 and electrode materials. Herein, a hierarchical cathode architecture based on different discharge characteristics of α-MnO2 and Co3O4 is constructed, which can enable the embedded growth of large Li2O2 aggregations to solve this problem...

Understanding surface reactivity is crucial in many fields, going from heterogeneous catalysis to materials oxidation and corrosion. In order decipher the reactions of ZrB2 exposed harsh environment aerospace components, chemical activity both Zr- B-surfaces predicted compared by using density functional theory nudged elastic band methods. particular adsorption, dissociation diffusion O2, CO H2...

In this work, the effects of As-doped on the adsorption of oxygen gas on the outer and inner surface ofboron nitride nanotube (BNNTs) is investigated. The structural parameters, quantum properties involving:bond length, bond angle, HOMO-LUMO orbital, gapenergy, electron affinity, electronegativity, chemicalpotential, global hardness, global softness and NMR parameters of BNNTs are calculated at...

We report the electrical responses of thin and thick single-walled carbon nanotube (SWNT) networks to N2 and O2 adsorption. In the surface desorbed state exposure to N2 and O2 provide an increase in conductance of thin and thick SWNT networks. The increase in conductance of both thin and thick networks is of a greater magnitude during O2 exposure rather than N2 exposure. Thin networks exhibit a...

Optical properties of metal oxide nanoparticles are subject to synthesis related defects and impurities. Using photoluminescence spectroscopy and UV diffuse reflectance in conjunction with Auger electron spectroscopic surface analysis we investigated the effect of surface composition and oxygen adsorption on the photoluminescence properties of vapor phase grown ZnO and MgO nanoparticles. On hyd...

The adsorption and dissociation of dioxygen on the Ir~111! surface have been studied using periodic self-consistent density functional theory ~DFT-GGA! calculations. Three di-s-type chemisorbed molecular precursors are identified: One is located over bridge sites and has a binding energy of 21.3 eV and a bond length of 1.4 Å; the other two are located over threefold hollows and have similar bin...

The adsorption and activation of both CO2 methanol are mainly affected by the distance Lewis acid site, Zr4+, base, Zr4+/O2−, Zr-based catalysts. In this paper, Zr-incorporated SBA-15 (Zr-SBA-15) Zr-grafted (Zr/SBA-15) catalysts were prepared with different Zr environments, analyzed N2 adsorption–desorption isotherms, X-ray diffraction, UV-vis spectra, XPS. It was proposed that Zr-SBA-15 cataly...