Practical and environmentally friendly! The new catalyst in the United States makes CO emission close to zero during hydrogen pr
Although hydrogen is ubiquitous in the atmosphere, the cost of manufacturing and collecting molecular hydrogen for transportation and industrial applications is very high. Duke University engineers in the hydrogen reaction in the use of a new catalyst, this new catalyst can make hydrogen production process of carbon monoxide emissions close to zero, but also to make the production process has become more simple.
Duke University engineers in the hydrogen reaction using a new catalyst. The results show that the new method can reduce the concentration of carbon monoxide (CO) to zero at the same time when hydrogen is produced, and the temperature required for new reaction is lower than that of the traditional method, so it is more practical. The study was published in the Journal of Catalysis.
Although hydrogen is ubiquitous in the atmosphere, the cost of manufacturing and collecting molecular hydrogen for transportation and industrial applications is very high and the process is complex. At present, most methods of hydrogen production will produce toxic carbon monoxide to humans and animals.
The latest method of making renewable energy is to use ethanol-based raw materials extracted from biomass, such as methanol. When methanol is treated with steam, a hydrogen-rich mixture of fuel cells can be produced. "The main problem with this approach is also the production of carbon monoxide, and a small amount of carbon monoxide can quickly destroy the fuel cell," says Nick Hortz, the first author of the study and an assistant professor of mechanical engineering and materials at the Duke University School of Engineering. Performance-critical catalyst on the battery membrane. "
"Nowadays, everyone wants to be able to produce useful energy in a sustainable and less polluting way, instead of fossil fuels," says Hertz Laboratories graduate student Tirey Sodia. "Our ultimate goal is Manufacturing of fuel cells for the use of hydrogen.With the traditional method of using gold nanoparticles as the only catalyst is different from our new reaction using gold and iron oxide nanoparticles as a catalyst combination.The new method can continue to produce hydrogen, the resulting Carbon monoxide concentration of only 0.002%, while the by-products of carbon dioxide and water. "
Sodia explains: "It has always been thought that iron oxide nanoparticles are merely 'containers' of gold nanoparticles, and gold nanoparticles are responsible for the reaction, but we find that increasing the surface area of iron oxide can significantly increase the number of gold nanoparticles Of the catalytic activity.
Researchers to the new reaction carried out more than 200 hours, found that the catalyst to reduce the hydrogen-rich mixture of carbon monoxide in the capacity of the capacity has not decreased. In this case,
"Although the size of gold nanoparticles is critical to the reaction, future research should focus on the role of iron oxide particles in chemical reactions," Sodia acknowledges: "At present, we do not yet know what the mechanism is for the new reaction . "
Carbon monoxide pollutants on the human body
Carbon monoxide (CO) is a highly toxic pollutant to the blood, and the nervous system. Carbon monoxide (CO) in the air, through the respiratory system, enters the human blood and hemoglobin (hemoglobin) in the blood. Muscle in the myoglobin. Respiratory enzymes containing ferrous iron combine to form reversible conjugates.
The combination of carbon monoxide and hemoglobin not only reduces the ability of blood cells to carry oxygen, but also inhibit and delay the analysis and release of oxygen hemoglobin (o2hb), leading to tissue necrosis due to hypoxia, severe cases may endanger human life.
Under normal circumstances, through the respiratory system into the blood of oxygen, will be combined with hemoglobin (hb), the formation of oxygen hemoglobin (o2hb) is transported to the body of the various organs and tissues to participate in normal metabolic activity. If the concentration of carbon monoxide in the air is too high, a lot of carbon monoxide will enter the body's blood. Into the blood of carbon monoxide, with the priority hemoglobin (hb) to form carboxyhemoglobin (cohb), carbon monoxide and hemoglobin than oxygen and hemoglobin binding force of 200-300 times. The dissociation rate of carboxyhemoglobin (cohb) is only one-third of that of oxygen hemoglobin (o2hb).
Carbon monoxide on the degree of harm to the body, mainly depends on the concentration of carbon monoxide in the air and the body absorbs high concentrations of carbon monoxide in the air for a long time. Carbon monoxide poisoning in the blood of carboxyhemoglobin (cohb) content and concentration of carbon monoxide in the air is proportional to the relationship between the severity of poisoning and blood carboxyhemoglobin (cohb) content is directly related. In addition, the body's hemoglobin (hb) metabolism process, but also produce carbon monoxide, the formation of endogenous carboxyhemoglobin (cohb). Normal body, the general carboxyhemoglobin (cohb) accounted for only 0.4-1.0%, anemia patients will be higher.
The practical use of the catalyst
In the chemical production, scientists experiments and life activities, catalysts are to show their talents. For example, the production of sulfuric acid to use vanadium pentoxide as a catalyst. From nitrogen and hydrogen synthesis of ammonia, to use iron-based multi-group catalyst to improve the reaction rate. In the refinery, the catalyst is indispensable, the choice of different catalysts, you can get different qualities of gasoline, kerosene. Chemical synthesis of acid and alkaline color catalyst can 赛 Sai. Car exhaust gas containing harmful carbon monoxide and nitric oxide, the use of platinum and other metals as catalysts can quickly transform the two into harmless carbon dioxide and nitrogen. Enzymes are plant, animal and microbial production of catalytic capacity of the protein, the chemical reaction of the body almost all in the enzyme under the catalysis, brewing industry, the pharmaceutical industry and so on with the catalyst.
We can observe in the Boltzmann distribution and the energy profile that the catalyst allows the chemical reactant to flow through the path with less activation energy, without change, To carry out a chemical reaction. And usually in this energy, the molecule is not unable to complete the chemical reaction, or it takes a long time to complete the chemical reaction. However, in the presence of a catalyst, the molecule needs less energy to complete the chemical reaction.
New approaches to development
Chemical bonding method. This process is now widely used in the manufacture of polymerization catalysts. The purpose is to solidify the homogeneous catalyst. Carriers chemically bonded to the transition metal complex have certain functional groups on the surface (or chemically treated functional groups) such as the -X, -CH2X, -OH groups. Arsenazo or amines, and then using the surface of phosphorus, arsenic or nitrogen atoms of the lone electron pair transition metal complexes with the center of the metal ions in the collocation network (http://www.agile-news.com/). Chemical synthesis of solid-phase catalyst, such as propylene bulk liquid phase polymerization carrier Ziegler-Natta catalyst for the manufacture.
Fibrosis method. For the manufacture of supported catalysts containing precious metals. Such as the borosilicate glass fiber drawn into the wire, with concentrated hydrochloric acid solution corrosion, into a porous glass fiber carrier, and then impregnated with chloroplatinic acid solution, to carry platinum components. Depending on the practical situation, the fibrous catalyst is compressed into various shapes and densities as required, such as catalysts for automotive exhaust oxidation, which can be compacted in a short round tube. If the oxidation process is not used, carbon fibers may also be used. The manufacturing process of the fiber catalyst is complicated and the cost is high.