Ethanol Catalytic Combustion Research Articles

Atmospheric Environment Fabrication of Composite Films by Ethanol Catalytic Combustion and Its Use as Counter Electrodes for Dye-Sensitized Soar Cells

The composite films which consist of amorphous carbon, carbon nanotube, and iron nanoparticles were prepared by ethanol catalytic combustion in atmospheric environment. The as-prepared composite films have good electrocatalytic activity and high conductivity which is due to their particular structure. The efficiency of the composite films based dye-sensitized soar cells (DSSCs) is closed to that of the Pt based one. Most importantly, the DSSC employing the composite films presents a higher FF than those of Pt based solar cell. In addition, it is a simple method for mass production of composite films counter electrode (CE) which is expected to reduce the cost of fabricating DSSCs.

Effects of synthesis conditions on the synthesis of carbon nanofibers by ethanol catalytic combustion

In this paper, the effects of position of substrates in flames, preparation time, stability of flames and catalyst precursors on the synthesis of carbon nanofibers (CNFs) by ethanol catalytic combustion (ECC) were investigated. For investigating the effects of these influence factors on the synthesis of CNFs, several sets of controlled experiments were performed, such as preparation experiments with different position of substrates in flames, different preparation time, stable and unstable flames, and different catalyst precursors. In our experiments, the catalyst precursors were iron nitrate, cobalt nitrate, nickel nitrate, and iron chloride, cobalt chloride, nickel chloride. The as-synthesized products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. Our results indicate that the optimal position of substrates in flames is more than 1cm and less than 2.5cm, the optimal preparation time is more than 5min and less than 30min for massive yield, stable flames would be tent to synthesize CNFs with mainly single-type morphology and could improve the graphitization of CNFs, and the catalyst precursors obviously have effects on the synthesis of CNFs.

Effects of Synthesis Parameters on the Preparation of Carbon Nanofibers by Ethanol Catalytic Combustion

In this paper, the effects of position of substrates in flames, preparation time and stability of flames on carbon nanofibers are investigated in ethanol catalytic combustion. For the position of substrates, our results indicate that the temperature at the lower height (h<1cm) is too low (less that 500°C) to grow carbon nanofibers; the temperature at higher height (h>2.5cm) is suitable for the growth of carbon nanofibers, but the carbon source is insufficient because of sufficient combustion of ethanol; the optimal position of substrates in flames is more than 1cm and less than 2.5cm for massive yield because the temperature of flames is suitable for the growth of carbon nanofibers and the carbon source is also sufficient. For the preparation time, our results indicate that the optimal preparation time is more than 5min and less than 30min for massive yield. If the preparation time is excessive long (more that 30min), the deposits partly become burning in flames due to excessive products on substrates. The stability of flames has effects on the morphology and graphitization of products. Our experimental results indicate that stable flames prefer to produce noncoiled carbon nanofibers with relatively good uniformity and higher graphitization because the relatively stable flames could provide a relative stable synthesis environment.

The Effects of Nano Pt/Carbon Black Compound Coating on the Electro-Catalysis Properties of the Graphite Electrode

The modification of Nano Pt and carbon black compound coating on the fuel cell’s graphite electrode by the method of vacuum ion plating and ethanol catalytic combustion. The microstructures and the electro catalysis properties of the electrode surface before and after the modification were analyzed and tested with the methods of scanning electron microscope(SEM), transmission electron microscope(TEM), electrochemical workstation and so on. The effects of nano Pt and carbon black on the electrode’s electro catalysis properties were investigated. The Study results have shown that carrying on electrochemical properties test to the graphite electrode which has been treated with nano Pt and carbon black compound surface modification, there will be three oxidation peaks in its cyclic voltammograms and the background current will be higher. Compared with the nano Pt surface modification, the electrode which has been treated with nano Pt and carbon black compound surface modification has better ethanol electro catalysis properties. The high specific surface area acquired from the nano carbon black surface modification and the synergic action of the catalytic material Pt can improve the ethanol electro catalysis properties of the electrode effectively.

Ethanol oxidation over Au/TiO<sub>2</sub> catalysis

The adsorption and reaction of ethanol over Au/TiO2 catalysts was investigated using pulse flow reactor, DRIFTS, and TPD. The adsorption of ethanol over TiO2 (P25) indicated a full monolayer adsorption of ethanol, with much of it in a dissociative state, forming ethoxy group on the cationic sites and hydroxyl group at anions. The ethoxy is relatively stable until 300oC, at which point dehydration to ethene occurs by a bimolecular surface reaction. As the concentration of ethoxy on the surface disappears, so the mechanism reverts to a decomposition pathway, producing methane, CO and hydrogen (~320oC) in TPD. However, the presence of gold on the catalysts prepared by deposition precipitation method indicates that the reaction is complete oxidation to CO2 and water similar to Titania. The effect of the presence of low level of gold is marked with complete conversion of ethanol at low temperature (220oC) lower than Titania (240oC).Simultaneously, ethanol oxidation on Au/TiO2 catalyst was followed by dehydration to ethene at 300oC (characteristic of TiO2) and dehydrogenation to ethanal at high temperature. The pathway which gives ethene as seen on TiO2 remains, but a new feature of the reaction is the evolution of CO2 and H2 (a peak is seen in TPD above 350oC) and appears to be due to the production of formate species on the surface of the catalysts. This formate species is mainly involved in the complete oxidation reaction of ethanol on the catalysts. Keywords: Au catalysis, ethanol oxidation, ethanol catalytic combustion, TPD, DRIFTS

Carbon Nanotubes Grown by Ethanol Catalytic Combustion with an Additive of Thiophene

Combustion method is a simple method to synthesize carbon nanotubes(CNTs), which employs flames of carbon-contained reactant to synthesize CNTs. It has been proved that combustion method is an effective method to synthesize carbon nanotubes and carbon nanofibers. In this paper, we reported the synthesis of CNTs by using ethanol catalytic combustion with an additive of thiophene, which employed ethanol as carbon source and fuel, nitrate as catalyst precursor, stainless steel as substrate, and thiophene as accelerant. Compared with previous reports on the synthesis of CNTs by ethanol catalytic combustion, great yield of CNTs were obtained with adding thiophene in ethanol. The reproducibility of the synthesis of CNTs in the case of adding thiophene in ethanol was greatly improved.

Co‐growsth of Straight and Coiled Carbon Nanofibers by Ethanol Catalytic Combustion Technique

We have successfully fabricated straight carbon nanofibers containing coiled carbon nanofibers by ethanol catalytic combustion technique. In our experiment, copper plate was employed as substrate, transition metal salt solution as catalyst precursor, and ethanol as carbon source. The morphology and microstructure of the obtained carbon nanostructures have been investigated and their growth mechanism has been discussed.

Effects of Catalysts on Carbon Nanofibers Synthesized by Ethanol Catalytic Combustion

It is very important to study the effects of various factors on synthesis of carbon nanomaterials for controlled synthesis, which plays a significant role in realizing desired nanostructures or nanodevices for applications. In this report, we employed iron nitrate, cobalt nitrate, nickel nitrate, iron chloride, cobalt chloride and nickel chloride as catalyst precursors, and studied the effects of catalyst precursors on carbon nanofibers that were synthesized by ethanol catalytic combustion process. The as‐grown carbon deposits have been characterized by scanning electron microscopy and transmission electron microscopy for deep understanding. The experimental results suggested that the carbon deposits synthesized by employing iron salt, cobalt salt, and nickel salt as catalyst precursors had different unique characteristics, respectively.

Synthesis of carbon nanofibers by ethanol catalytic combustion technique

A general, simple and economic synthetic method for synthesizing carbon nanofibers was presented. In the method, ethanol was employed as carbon source; metal salts such as nickel nitrate, ferric nitrate and ferric chloride were used as catalyst precursor respectively; copper plate was employed as the support material. A lot of products were obtained by catalytic combustion deposition of ethanol vapor. Then the as-prepared carbon nanofibers were characterized by field-emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, energy dispersion X-ray spectroscopy and selected-area electron diffractometry. By analyzing the results of characterization, the conclusions are as follows: 1) the large catalyst particles tend to form large-diameter CNFs, small catalyst particles are inclinable to form small-diameter CNFs; 2) the morphology of the catalyst can affect the final morphology of the CNFs. Moreover, the possible growth mechanisms were proposed and the degree of graphitization of samples was estimated by Raman spectroscopy characterization.

Carbon Nanotubes Obtained by ECC Technique with Cobalt Salt as Catalyst Precursor

In this paper we report the preparation of carbon nanotubes (CNTs) by ethanol catalytic combustion (ECC) technique. We employed cobalt salt as catalyst precursors, copper plate as substrate and ethanol as carbon source. In order to have a better understanding of the growth mechanisms, we employed cobalt chloride, cobalt nitrite and cobalt sulfate as catalyst precursor to study the influence of catalysts on CNTs growth respectively. Entangled and nonseparated CNTs were aggregated together when the catalyst precursor was cobalt chloride, while straight and uniform CNTs were obtained when the catalyst precursor was cobalt sulfate. In the case of using cobalt nitrite as catalyst precursor, the CNTs tend to form helical and disordered structure. We have examined the morphology and microstructure of the obtained CNTs and discussed the growth mechanism.

Carbon Nanostructures by Using FeCl<sub>3</sub> as Catalyst Precursor

Carbon nanotubes and carbon nanowires were synthesized by ethanol catalytic combustion (ECC) technique, using FeCl3 solution as a catalyst precursor. Applying the 0.01 mol/l, 0.1 mol/l and 1 mol/l FeCl3 as catalyst precursor solution to the copper plate, carbon nanotubes and carbon nanowires were synthesized. The effect of concentration on growth and structural changes of the as-grown nanomaterials are illustrated and discussed. This technique has advantages of low cost, large scale production and flexible reaction conditions, etc. This technique can be used to synthesize carbon nanotubes and nanowires on metal substrate directly. This technique also has potential applications for fabricating nano-electrical devices.

Synthesis of Carbon Nanofibers by Ethanol Catalytic Combustion Technique

In this paper, we report a simple growth of carbon nanofibers by means of the combustion of ethyl alcohol. In our experiment, copper plate was employed as substrate, iron nitrate and iron chloride as catalyst precursor and ethanol as carbon source. The as-grown carbon nanofibers were characterized by employing scanning electron microscopy, transmission electron microscopy, high-resolution field-emission transmission electron microscopy and Reinshaw optical confocal Raman spectroscopy. Our results suggested that it would tend to form relatively uniform nanofibers when the catalyst precursor was iron nitrate, however, to form some helical structure nanofibers when the catalyst precursor was iron chloride. The sample using iron chloride as the catalyst precursor has a higher graphitization degree than that using iron nitrate as the catalyst precursor.

Catalytic Combustion Synthesis of Carbon Nanofibers

The catalytic combustion technique was used to synthesize carbon nanotubes and carbon nanofibers. In this paper, we report that carbon nanofibers were synthesized by ethanol catalytic combustion technique. The as-grown products were characterized by means of scanning electron microscopy, transmission electron microscopy, Raman spectroscopy. The results showed that the products have a mass of carbon nanofibers. However, morphology and microstructure of carbon nanofibers are affected by synthesis conditions, such as stability of flames and sampling time, sampling temperature etc. Different Influence factors were depicted in detail. Ethanol catalytic combustion technique offer a simple method to synthesize carbon nanotubes and carbon nanofibers, it also has some advantages, such as flexible synthesis conditions, simple setup, and environment-friendly.

Effects of Concentration of Catalyst Precursors on Carbon Nanostructures

It is very important to study the effects of various factors on synthesis of carbon nanomaterials for controlled synthesis, which plays a significant role in realizing desired nanostructures or nanodevices for applications. In this report, we employed iron nitrate solution with different concentration, such as 1 mol/l, 0.1 mol/l, 0.01 mol/l, and saturated iron nitrate solution as catalyst precursor solution and studied the effects of concentration of catalyst precursor solution on carbon nanostructures that were synthesized by ethanol catalytic combustion (ECC) process. We have characterized the as-grown carbon nanostructures by employing scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for deep understanding.

Synthesis of Y-junction carbon nanofibres by ethanol catalytic combustion technique

Y-shaped structure was synthesized by ethanol catalytic combustion(ECC) technique on the copper plate substrate, without directly seeding catalyst into the flame. The as-grown Y-junction carbon nanofibres were investigated by transmission electron microscopy (TEM). The very common laboratory ethanol burner was used for synthesizing carbon nanofibres. Two kinds of the catalyst precursor, which are iron nitrate (Fe(NO 3) 3) and nickel nitrate (Ni(NO 3) 2), were respectively employed to assist the formation of Y-junction carbon nanofibres. TEM analysis confirm the formation of Y-junction in the coiled and noncoiled carbon nanofibres. The type of the catalyst is found to be crucial to grow different Y-junction carbon nanofibres. Different Y-shaped structure may possess different mechanical and electronic properties. These three-terminal nanofibres provide the nanoelectronics community with a novel material for the development of molecular-scale electronic devices.

Synthesis of bamboo-like carbon nanotubes by ethanol catalytic combustion technique

Bamboo-like carbon nanotubes were synthesized by ethanol catalytic combustion (ECC) technique with combustion method. Copper plate was employed as substrate, ethanol as carbon source, and iron chloride as catalyst precursor. The as-grown black powder was characterized by means of scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that the thinner bamboo-like carbon nanotubes have a relatively good structure that the compartment layers are more regular, while the thicker carbon nanotubes have a relatively irregular bamboo-like structure; the proposed method is simple to synthesize bamboo-like carbon nanotubes and has some advantages, such as flexible synthesis conditions, simple setup, and environment-friendly.

Effects of catalyst precursors on carbon nanowires by using ethanol catalytic combustion technique

Iron nitrate, nickel nitrate and cobalt nitrate were used as catalyst precursors to study their effects on carbon nanowires synthesized by ethanol catalytic combustion (ECC) process. The as-grown carbon nanowires were characterized by means of scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that relatively uniform nanowires will be formed when the catalyst precursor is iron nitrate; while helical structure or disordered structure will be formed when the catalyst precursor is nickel nitrate or cobalt nitrate.

Preparation of carbon nanotubes by ethanol catalytic combustion technique using nickel salt as catalyst precursor

A simple growth technique of carbon nanotubes (CNTs) by combustion of ethanol was developed. In the experiment, copper plate was employed as substrate, nickel nitrate (Ni(NO 3) 2) and nickel chloride (NiCl 2) as catalyst precursor, and ethanol as carbon source. The cleaned copper substrate was dipped into catalyst precursor solution for mounting catalyst precursor particles. The dip-coated substrate was then placed into ethanol flame for about 10 min after drying. The black wool-like production grown on copper plate was obtained. This route is called an ethanol catalytic combustion(ECC) process. The black powders were characterized by means of scanning electron microscopy(SEM), transmission electron microscopy(TEM), energy dispersive X-ray spectrometer(EDS) and Raman spectroscopy. The results show that the techique is much simpler and more economical to meet the future broader applications.