Effect of Temperature and N-Doping on the Distribution of Bamboo Waste Pyrolysis Products Using Quartz Tube Furnace

Synergistic effect of nitrogen and oxygen dopants in 3D hierarchical porous carbon cathodes for ultra-fast zinc ion hybrid supercapacitors

For thin-film sensor applications, the mechanical properties, such as the hardness and elastic modulus, of the sensing material are important in addition to its electrical properties. The mechanical properties of the material need to be known at the design stage of the sensor because these properties are influenced by doping. The effect of in situ nitrogen doping on the mechanical properties of 3C-SiC (111) thin films are presented in this paper. These films are deposited at a pressure of 2.5 mbar and a temperature of 1040 °C on thermally oxidized Si (100) substrates from methyltrichlorosilane and ammonia using a resistively heated vertical hot-wall low-pressure chemical vapour deposition reactor. The effect of in situ nitrogen (0, 9 and 17 atomic per cent of nitrogen) doping on the mechanical properties of the material is investigated using nanoindentation. The x-ray diffraction patterns of 3C-SiC thin films show a decrease in the crystallanity and the intensity of the peak (111), with an increase in the dopant concentration from 0 to 17 atomic percent (%). AFM investigations show a decrease in the roughness and an increase in grain size of the 3C-SiC thin films with an increase in the nitrogen concentration. Nanoindentation measurements revealed that the elastic modulus and hardness of nitrogen doped 3C-SiC thin films decreased from 353 ± 5 to 178 ± 3 GPa and from 35 ± 1.4 to 22 ± 0.6 GPa, respectively, with an increase in the nitrogen doping concentration. This study shows that the mechanical properties of films strongly depend on the grain size, which is influenced by the effects of nitrogen doping. The elastic modulus and hardness are found to be 178 GPa and 22 GPa, respectively, for 3C-SiC thin films doped with 17 atomic % of nitrogen concentration, making it suitable as a sensing material for sensor applications.

Effect of N-doping on visible light activity of TiO2–SiO2 mixed oxide photocatalysts

Influence of temperature on the distribution of gaseous products from pyrolyzing palm oil wastes

Graphene has attracted a lot of attention due to its excellent electrical properties, however, the gapless nature of graphene limits its further applications. Doping is an effective way to open the bandgap, in which nitrogen-doped (N-doped) graphene has potential applications, but the study of its tribological properties is still lacking. In this work, the effects of nitrogen doping on the tribological properties of graphene under different interfacial structures are investigated by molecular dynamics simulation. The simulation models include a hexagonal graphene sheet, graphene or N-doped graphene substrate. The results show that the nitrogen doping has different effects on friction when interface structure is in a commensurate state and an incommensurate state. In a commensurate state, N-doping reduces the friction between interfaces in all cases, but the friction first goes up and then decreases with the increase of doping ratio of nitrogen. The local maximum value of friction occurs at a doping ratio of 7.5%. This phenomenon results from the interface structure and the change of van de Waals force between interfaces. The introduction of nitrogen atoms causes the lattice of graphene to distort, which results in the formation of local incommensurate state, thus reducing the interfacial potential barrier and friction. However, the van der Waals force between nitrogen atom and carbon atom between layers is stronger than that between carbon atoms and carbon atoms, which causes the friction to increase. When the doping ratio is low or high, lattice distortion plays more important role. The friction of N-doped graphene shows much smaller increase with load than that of ideal graphene, which indicates that the N-doped graphene possesses a better performance under high load. When the interface structure is in an incommensurate state, the introduction of nitrogen atoms shows slight influence on lattice mismatch, therefore, the change of atomic type plays a dominant role in determining the friction between interfaces, which goes up with the increase of N-doping ratio. When the substrate is graphene with vacancy defects, the value of friction between interfaces is larger than the ideal graphene substrate or N-doped graphene substrate, which indicates that the doping of nitrogen atoms has positive effect on reducing the friction of graphene with defects.

Effect of nitrogen doping on characteristics of SiTe Ovonic threshold switch for selectors

The effects of nitrogen doping on Ge2Sb2Te5 (GST) films for chemical mechanical polishing (CMP) and their performance were investigated. Nitrogen doping was controlled using a rapid thermal annealing system with nitrogen gas flow rates that varied from 0 to 20 sccm at 300 °C. The material removal rate, surface characteristics and crystal structure of the nitrogen doped GST films after CMP were examined by X-ray diffraction (XRD), scanning electron microscopy, and atomic force microscopy. XRD patterns revealed that the intensities of crystalline diffraction peaks decreased with increasing nitrogen flow rate. With increasing flow rate, the material removal rate and surface roughness of GST films reduced owing to nitrogen doping effects. Current–voltage (I–V) characteristics of the nitrogen doped GST films after CMP showed changes in the threshold voltage owing to changes in crystallization and surface roughness. Further, Nitrogen doped GST films in CMP showed a strong correlation with material removal rate, surface roughness, and crystallization.

A theoretical model to study the impact of nitrogen-doping on the plasma-assisted growth and field emission properties of the graphene sheet (GS) has been developed. The model incorporates the charging rate of the GS, kinetics and energy balance of all plasma species i.e., electrons, positively charged ions and neutral atoms along with the nitrogen doping species, and growth rate of the GS. Numerical calculations on the effect of nitrogen doping on the thickness of the GS have been carried out for typical glow discharge parameters. It is found that the thickness of the GS decreases with nitrogen doping. The ramifications of nitrogen doping on the field enhancement factor of GS have likewise been examined on the premise of the above result. It is observed that the nitrogen doped GSexhibits better field emission as compared to undoped GS. Some of the results of the present investigation are in compliance with the experimental observations.

A comparative production and characterisation of fast pyrolysis bio-oil from Populus and Spruce woods

In practice, modifying the fundamental properties of low-dimensional materials should be realized before incorporating them into nanoscale devices. In this paper, we systematically investigate the nitrogen (N) doping and oxygen vacancy (OV) effects on the electronic and magnetic properties of the beryllium oxide (BeO) monolayer using first-principles calculations. Pristine BeO single layer is a non-magnetic insulator with an indirect K–Γ gap of 5.300 eV. N doping induces a magnetic semiconductor nature, where the spin-up and spin-down band gaps depend on the dopant concentration and N–N separation. Creating one OV leads to the energy gap reduction of 31.06% with no spin-polarization, which is due to the abundant 2p electrons of the Be atoms nearest the OV site. The further increase to two OVs and varying the OV–OV distance affect the band gap values, however the spin independence is retained. The magnetic semiconducting behavior is also obtained by the simultaneous N doping and OV presence. Calculations reveal significant magnetization of the BeO@1N, BeO@2N-n, BeO@NOV-n systems, which is produced mainly by the spin-up N–2p state. Except for the BeO@NOV-1 and BeO@NOV-2, whose magnetic properties are created by the spin-up 2p state of the Be atoms closest to the OV site. The variation of the N–N and N–OV distances keeps the ferromagnetic ordering in the BeO@2N and BeO@NOV layers. Results presented herein may propose efficient methods to artificially modify the physical properties of BeO monolayer, leading to the formation of novel two-dimensional (2D) materials for optoelectronic and spintronic applications.

The influence of nitrogen source and doping sequence on the electrocatalytic activity for oxygen reduction reaction of nitrogen doped carbon materials

Nitrogen doped multi walled carbon nanotubes produced by CVD-correlating XPS and Raman spectroscopy for the study of nitrogen inclusion

Aquathermolysis experiments over the temperature range 360 to 422 ºC were performed on core samples taken from three large bitumen and heavy oil deposits found in Alberta: Athabasca, North Bodo, and Frisco Countess. The purpose of this work was to facilitate the development of comprehensive thermal cracking models for predicting gas and liquid phase product distributions under conditions anticipated during thermal recovery. Previous studies. have shown by material balance on oxygen that water is implicated in many of the chemical reactions leading to the formation of H2S and CO2, yet most of the reported thermal cracking studies have not included water. Additionally, experimental investigations in this area have, for the most part, not involved realistic time frames, and as such certain phenomena observed in this work have not been previously reported. The experiments conducted using Athabasca bitumen included runs with an initially previously oxidized oil sample (designed to simulate conditions preceding the arrival of the firefront during in situ combustion) and runs with a change in core mineralogy. Pre-oxidizing the oil was found to substantially increase the amount of H2 generated. Core mineralogy played an important role in the generation of CO2; and the amount of H2S produced was. dependent on oil composition, mineralogy, and time. Gas production was observed to be largely associated with the conversion of the heavy. oil and asphaltenes oil fractions. The cracking models developed in this work offer useful directional insight as to the effect of core mineralogy and oil composition on the kinetic parameters, and a much needed means of estimating the calorific value and acidic gas content of the produced gases during thermal recovery operations. Introduction The purpose of this work was to develop thermal cracking models capable of describing the liquid and gas phase compositional changes that occur during thermal recovery operations. Although rather extensive laboratory studies have been performed concerning the thermal cracking of heavy oils and bitumen, few in comparison have included water as part of the reactants. Laboratory studies(1, 2, 3) and field applications of thermal recovery processes(4) have demonstrated that appreciable amounts of gaseous environmental contaminants such as H2S and CO2 arecreated by the aquathermolysis (steam/oil reactions) of heavy oils. hese problems are all the more severe as the sulphur and oxygen content of the oil increases(5). It has also been demonstrated(2) that H2 and light saturated hydrocarbons are also produced by steam/oil reactions over the temperature range 200 to 300 ºC. Accordingly, casing gas produced from cyclic steam stimulation projects has sometimes been collected and condensed yielding between 0.015 and 1.5 m3 of condensate per well per day(6), with the noncondensible gas (which contains mostly methane) being used as a supplementary fuel for the steam generators. Thus, aside from the pollution aspect there is the potential to recover chemical energy from the effluent gases. In this paper we present thermal cracking models based on aquathermolysis experiments performed on core samples from three large bitumen and heavy oil deposits in Alberta: Athabasca, North Bodo, and Frisco Countess. The oils from these deposits have contrastingly different elemental compositions and API gravities. For the experiments involving Athabasca oil sands we report on three sets of tests: two involving significantly different core minera

Pyrolysis of palm oil wastes for enhanced production of hydrogen rich gases

Nitrogen doped graphene/CuCr2O4 nanocomposites for supercapacitors application: Effect of nitrogen doping on coulombic efficiency