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Nissan to Introduce New Ultra-Low Precious Metal Catalyst in the Cube

The new ultra-low precious metal catalyst. Click to enlarge.

Nissan Motor Co. will introduce its ultra-low precious metal catalyst on the new Cube for the Japan market, to be launched on 19 November. The new catalyst utilizes half the amount of precious metals compared with conventional catalysts. (Earlier post.)

A high percentage of world’s reserves of platinum (50%) and rhodium (80%) are used in the automotive industry as catalysts. The standard three-way catalyst (TWC) device for emissions treatment consists of a mixture of platinum (Pt), rhodium (Rh) and palladium (Pd).

Within the catalyst, the chemical reaction between the precious metals and exhaust gases contributes to the conversion of nitrogen oxides (NOx), carbon monoxide (CO) and hydrocarbons (HC) into non-toxic compounds such as nitrogen (N2), water (H2O), and carbon dioxide (CO2).

Catalytic activity of the noble metals is roughly proportional to their exposed surface area, since catalytic reactions provided by noble metals are contact reactions. To obtain the greatest extent of catalytic activity from a small amount of noble metal, manufacturers fabricate particles that are small in size, with a high specific surface area.

The Nissan engineers who developed the new catalyst note:

...in the case of minute particles in which the noble metal grain size is 1 nanometer (nm) or smaller, the surface reactivity of the noble metal particle is high and the noble metal particle has a large surface energy, so they are extremely unstable. For this reason, particles of noble metals readily cohere to each other (by sintering) when brought together at high temperature. Pt in particular undergoes marked sintering when heated, so even when supported on a carrier in a dispersed manner, sintering causes grains to coalesce and thus the average grain size increases and thus the catalytic activity decreases.

“Nissan engineers approached the problem from a physical perspective rather than a chemical perspective in order to achieve the breakthrough.”
—Masanori Nakamura

Exhaust catalysts in automobiles are routinely subjected to high temperatures in the range of 800-900° C, and even in excess of 1,000° C, making it difficult to maintain catalytic activity. To compensate, existing catalyst devices contain higher amount of precious metals in order to maintain an efficient level of cleaning. This, however, pushes costs up.

Nissan’s new material uses a wall material to prevent clustering of the precious metals. Click to enlarge.

With Nissan’s technology, the precious metal attached to the substrates are separated by a “wall material” which prevents clustering of the precious metals, leading to improved cleaning efficiency.

Masanori Nakamura, manager of the Nissan Research Center, explained the concept using the analogy of “eggs protected in a bird’s nest”.

The new under-floor catalyst to be introduced in the next generation Cube uses half the amount of precious metals, from 1.3 grams down to .65 gram. Efficiency is improved with 75% less nitrogen oxides (NOx) and non-methane hydrocarbons (NMHC) emitted, lower than the Japan 2005 exhaust emission standards.

Nissan will produce the ultra-low precious metal catalyst in its Yokohama Plant for the domestic vehicle market. This catalyst and method for manufacturing the catalyst has been developed under the Renault-Nissan Alliance, and future applications of the approach will include Renault vehicles and diesel engines as well as potential for non-automotive application.




Truly remarkable

Henry Gibson

It may be that a different approach need to be taken to allow for complete combustion, But the ceramic companies have made great devices for improving combustion, and perhaps they should be used in house furnaces as well. ..HG..

Andrey Levin

HG, Google - catalytic stove -


What is the recyclability of this vs old style catalysts ?
While this uses fewer precious metals, if it is harder to recycle, it might not be such a good deal.


Maybe with less PM they will be worth less at the scrapyard and the bad guys won't have as much of a reason to steal them.


The ceramic is probably Al2O3 so grind the whole thing dip it to Fluorohydric acid and get the metal back.


Platinum use is forced by natural cartel ressources. We don't need that in catalytic converter or fuelcell, it's a gimmick by e.p.a. There is other method that cost less.



And what are these alternatives to precious metal for catalytic converter ? I am just curious to know why Mazda Nissan and other are spending millions of $ just to reduce the amount of precious metal use if there is alternatives as you say. Noble metal are very unique in their catalytic properties, nanotechnologie can offer alternatves in the medium long term (like gold for example...) but nothing serious in the decade to come, at least not that I am aware of.

"the chemical reaction between the precious metals and exhaust gases contributes to the conversion of nitrogen oxides (NOx), carbon monoxide (CO) and hydrocarbons (HC) into non-toxic compounds such as nitrogen (N2), water (H2O), and carbon dioxide (CO2)."

If true then why the fight for EPA to declare CO2 a "pollutant?"

Cyril R.

CO2 is not a pollutant. It is a GhG and dumping tens of billions of tons extra into the atmosphere is undesireable so we have kick the habit, but it is not a pollutant. The EPA should get their semantics right, otherwise it may actually hurt their case. If CO2 is a pollutant, then O2 may also be called a pollutant, considering it is toxic in very high concentrations, but absolutely vital to life on earth in lower concentrations. Yet that is also true for CO2.

Water is also a pollutant. If you get to much of it in your lungs you'll die. 100% nitrogen will kill you. 100% oxygen will kill you. 100% water (drowning) will kill you.

CO2 from fossil fuel combustion isn't toxic to us in any way that would require us to make regulations about it, because it is dispersed into the atmosphere. With the possible exception of CO2 sequestration if the field leaks. And of course when you burn stuff in a poorly ventilated room. But otherwise I don't see the purpose of calling fossil fuel combustion derived CO2 a pollutant.

Seriously. What we need is GhG regulation and chemical/radiological pollutant regulation as seperate things. CO2 is only a pollutant in very high concentrations, which isn't a problem with fossil fuel burning.

Now, back on topic. Why not zirconia/ruthenium catalysts?

Max Reid

I read a news that new research found the method to use silver as a catalyst in Diesel engines. Silver belongs to gold family and is much cheaper than those PGM (Platinum Group Metals).

Hope all these new experiments works. As the functions of motor increases and the engine decreases, the catalyst use may also decrease.

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