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What is the catalytic activity of gold nanoparticles as catalysts?

Regarding the catalytic properties of gold, the first ionization ability of gold is very large, and it is difficult to lose electrons, so the interaction force between gold and surface molecules is usually very weak. At temperatures below 200 °C, even highly reactive molecules, such as hydrogen and oxygen, are not easily adsorbed on the surface of single crystal gold. Since the adsorption of molecules on the catalyst surface is a prerequisite for the catalytic reaction, it can be considered that elemental gold does not have good activity for hydrogenation and oxidation reactions. Gold does not have very good catalytic activity. In fact, the prerequisite for the catalytic activity of gold catalysts is to prepare highly dispersed nano scale gold particles.

The characteristics of nano-gold catalysts: low temperature activity, good selectivity, and environmental friendliness.

An obvious feature of gold nanoparticles as catalysts is low temperature activity.

When the nano-gold catalyst catalyzes some reactions, it can be at room temperature or even below 0 °C, and the real good catalytic activity, such as catalytic CO oxidation and O3 decomposition, can be carried out at room temperature. In fact, the activity of gold catalysts for most reactions occurs below 230 °C. However, the activity of gold catalysts above 230 °C is significantly lower than that of other precious metal catalysts.

Nano gold particle catalysts have good selectivity when catalyzing certain reactions, and their catalytic properties are usually different from other noble metal catalysts.

For example, in the hydrogenation of CO2 catalyzed by Au/Zno catalyst, although its catalytic activity to methanol is slightly lower than that of commercial Cu/ZnO-Al2O3 catalyst, its selectivity is higher.

The nanogold powdercatalyst is environmentally friendly. Nano-gold catalysts can purify some polluted gases in the environment under normal temperature and humidity conditions without consuming too much thermal energy.

In terms of hydrogen energy generation, the catalyst can provide some new green synthesis methods and processing processes.

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Something About Pure Nano Gold Powder

Can you imagine no bacterial clothing? Such clothing can be in the medical field is especially useful in health conditions, not only the important they can save a life! In particular, bacteria such as MRSA continue to threat the health of employees and medical clinics and medical centers with the whole world. Interestingly, a group of Professor developed a clothing anti bacteria, actually kill harmful microorganisms on the pants, shirt, etc..

Actually, numerous types of harmful bacteria exist in hospitals. However, MRSA causes the majority of the roughly 90,000 annual deaths that occur in the USA, due to bacteria.

Methicillin-resistant Staphylococcus aureus is the bacteria’s official name, although the media often refers to it as the “superbug.” MRSA can remain harmless sitting inside your nose or atop your skin. However, when you become weary, injured, or have undergone surgery recently, then MRSA can become harmful or even deadly.

One common way that MRSA can spread, is through clothing. Fortunately, some professors at Wilkes University (Pennsylvania) are working on a solution to this problem. They are using nanotechnology to sense bacteria and then destroy it. Nanotechnology involves working with objects that are so tiny that you need a powerful microscope to view them.

So what exactly are the searchers creating? They designed a machine that can coat fabrics with Pure Nano gold powder containing various materials. What are nanopowders, you ask? These are microscope particles whose diameters are tinier than one micrometer. In other words, they are roughly the viruses’ size. Because the naked eye cannot view them, a wearer of the treated clothing would not look like he had just rolled around in flour.

So how would the nanopowders work? After the special machine coats the fabric with the nanopowders, the fabrics could then detect and destroy particular bacteria that land on the surface of the clothing. Although washing clothing in antibacterial soap can currently destroy unwanted microbes, the nanopowders would perform that function between washings!

Unfortunately, even if the creation of the bacteria-killing fabric is a success, it might not appear on the market for several years. Until then, scrubs, such as cheap landau scrubs, are one of the best options for numerous types of medical personnel. Such attire is much more useful in preventing MRSA, than earlier medical attire and the original “medical attire”-street clothes, were.

In addition to being more hygienic than other types of clothing, scrubs also provide other benefits:

1、They are comfortable. Many people are even wearing scrubs for workouts, backpacking, and lounging. In fact, some people even wear scrubs as a substitute for pajamas!

2、They are available in a wide variety of colors, patterns, and sizes.

3、They are easy to wash, and they dry quickly.

Maybe one day we can purchase bacteria-killing clothing. Until that time, those in the medical field work can help prevent the spread of bacteria. The method includes clothes, transmission may limit microbial. Till clothing can make super bacteria skin, keep them at bay!

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Oxidation Catalysis by Pure Nano gold powder

The historical notion regarding the inability of gold to catalyze reactions has been discarded in view of recent studies, which have clearly demonstrated the high catalytic efficiency of supported nano-gold catalysts. Although nano-Au catalysts are known to catalyze a variety of reactions, the major focus has been on CO oxidation catalysis. In this work we focus on the important aspects related to the CO oxidation reaction. Special emphasis is placed on the studies undertaken on model nano-Au systems as these studies have considerably enhanced the understanding of the oxidation process. Pure Nano gold powder in a highly dispersed state can selectively oxidize CO in the presence of excess hydrogen (of tremendous interest to state-of-the-art low-temperature fuel cells); related studies are addressed in this review. The nano-gold catalysts have also been investigated for the direct vapor-phase oxidation of propylene to propylene oxide in the presence of molecular oxygen; these investigations are highlighted in this work.
Gold nano-particles confined in the walls of mesoporous silica (GMS) catalysts were successfully prepared by a novel and simple technique utilizing thioether functional groups in the walls of mesoporous silica to anchor HAuCl4. Calcination of the materials removed organic moieties and reduced the gold salt to gold nano-particles. In this procedure, the thioether groups were introduced into the silica wall via a co-condensation of tetraethyl orthosilicate (TEOS) with 1,4-bis(triethoxysily)propane tetrasulfide. These gold containing mesoporous catalysts have unusually high surface area and pore volume.
The catalysts were evaluated for the solvent free liquid phase oxidation of benzyl alcohol by molecular oxygen. High selectivity to benzaldehyde was obtained under the reaction conditions of 403 K, 15 atm and 5 h in an autoclave. The 1.5% GMS catalyst was also evaluated for oxidation of alcohols using toluene as solvent under flowing oxygen at atmospheric pressure at 353 K in a two-necked flask. Under these conditions the conversion of benzyl alcohol reached 100% after 2 h and it was demonstrated that the catalyst can be recycled three times without significant loss of activity.