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2025-02-28 Update From: SLTechnology News&Howtos shulou NAV: SLTechnology News&Howtos > IT Information >
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Shulou(Shulou.com)11/24 Report--
The original title: "your car has a substance 10 times more expensive than gold, so be careful to be targeted by thieves."
If the most vulnerable part of a battery car is the battery, which part of the car with more complex parts is more likely to be stolen?
On a dark and windy night, sleeping cars were "woken up" by the sound of metal tools-someone was "cutting" the parts of their chassis. But at the moment, the owners of the car are not aware of what is happening, and they will not hear the exhaust sound of the car "wailing" until the engine is turned on in the morning. And for careless owners, cars have to let black smoke out of their buttocks to send a distress signal: "the ternary catalytic converter on my chassis has been stolen!" .
Photo Source: pixabay three-way catalytic converter is the main part of the tail gas treatment system of automobile engine. It is not only thieves who have tampered with these parts, but also automakers that have been exposed as "emission doors" in recent years.
In September 2015, the US Environmental Protection Agency accused some diesel vehicles sold by Volkswagen of installing software designed to deal with exhaust emission tests to identify whether the vehicles were being tested. and adjust the exhaust treatment device during vehicle inspection to meet high environmental standards. Subsequently, Mercedes-Benz, Ford and other large automakers have been exposed the problem of emissions fraud. In China, it is reported that some car repair shops will help with the three-way catalytic converter on the car inspection fashion, which will be removed after the annual inspection.
But the question is, why do thieves and automakers go to so much trouble to install, disassemble and control the ternary catalytic converters of cars? Before we can answer this question, we have to go back to the 20th century, when catalytic converters were about to emerge.
Catalytic converters were born in the early 20th century, and Los Angeles was famous for its haze weather. In the days of haze, children are forced to stay at home and cannot go out, and hospital emergency rooms are crowded with patients with headaches and shortness of breath. The whole of Los Angeles is at a low ebb, which forces people from all walks of life to look for ways to solve the air pollution problem.
Dr Arie Haagen-Smit, a professor of chemistry at the California Institute of Technology, played a key role in the fight against haze. He began to study air pollution in 1948, discovering not only the chemical composition of haze, but also how haze is produced in the real world. He believes that the formation of haze is complex, involving the interaction of nitrogen oxides, hydrocarbons and sunlight.
Los Angeles, USA, shrouded by haze in 1948. (photo Source: UCLA Library Special Collections) in 1968, he joined the California Air Resources Board and found that air pollution sources can be divided into two categories-stationary sources and mobile sources, the former including large factories and the latter mainly cars. At that time, California decided to deal with the latter, that is, car emissions.
More importantly, Congress passed the Clean Air Act in 1970, and then-President Richard Nixon (Richard Nixon) was under great pressure to create the Environmental Protection Agency.
Photo source: pixabay for automobile exhaust, different models, engines, fuel and other factors will make its composition different. Generally speaking, however, automobile exhaust mainly includes three kinds of pollutants: unburned or partially burned hydrocarbons (HCs), carbon monoxide (CO) and nitrogen oxides (NOx, mainly NO). The Clean Air Act requires that vehicle emissions of HC, CO and NOx be reduced to 10 per cent of 1970 levels by 1976. Under the condition that no other solution can meet the requirements of such a stringent bill, catalytic converters in cars began to appear on the stage of history. And driven by many forces, the ternary catalytic converter was born in 1981 and has become the core of the automobile exhaust treatment device that has been used up to now.
Ternary catalytic converter is called ternary catalytic converter when a catalytic converter can simultaneously deal with three kinds of automobile exhaust: HC, CO and NOx.
The problem is that HC and CO are reductive substances, while NOx is oxidizing, so in order to convert toxic automobile exhaust into other non-toxic substances, oxidation and reduction reactions are needed respectively. Among them, HC is oxidized to carbon dioxide and water, CO is oxidized to carbon dioxide, and NOx is reduced to nitrogen.
This involves many complex processes, so it is necessary to find more efficient catalysts to convert more toxic tail gas into non-toxic products (that is, catalytic selectivity). Moreover, a large number of hydrocarbons will be produced when the car starts cold (when the engine starts at a low temperature). In order to prevent these substances from being discharged directly into the air, ternary catalysts need to play a role as soon as possible.
Scientists have found that platinum group metals (platinum, palladium, which belong to a class of precious metals) have higher intrinsic activity (the ability to catalyze the oxidation of HC and CO) than cheaper base metals (such as copper, iron, chromium) in HC and CO oxidation. However, before the lead-containing fuel was discarded, because the precious metal palladium reacted more easily with the lead in the fuel, the active center of the early ternary catalyst was platinum. It was not until several countries began to ban the sale of leaded fuel that palladium, which is cheaper than platinum, gradually began to "rise" in ternary catalysts.
In the ternary catalytic converter, oxidation reaction and reduction reaction take place at the same time. (photo source: Platinum Metals Rev., 1972, 16, 74486) in contrast, scientists spend more time looking for catalysts to reduce NOx. At first, scientists pinned their hopes on platinum group metal ruthenium, because they found that ruthenium is one of the best metals in catalytic NOx to nitrogen, but ruthenium oxides are very volatile, so how to stabilize ruthenium catalysts has become one of the biggest problems. However, in the end, they chose the platinum group metal rhodium because the oxide of rhodium is relatively stable and non-volatile, and rhodium has a higher catalytic performance for NOx reduction than platinum and palladium.
At present, in gasoline vehicles, ternary catalysts are mainly composed of palladium, and a small amount of rhodium is used for the conversion of NOx. Due to the different composition of exhaust gas, the ternary catalyst of diesel vehicle is mainly platinum and a small amount of rhodium.
Sometimes the temperature of automobile exhaust can be as high as 1100 ℃, and the car body is often bumpy during driving, so scientists have also found a honeycomb porous ceramic as a catalyst carrier to improve the thermal stability and mechanical strength of the active components. In order to distribute platinum group metals evenly on the carrier, scientists are constantly updating the technology to obtain honeycomb ceramics with more "honeycomb chambers" to increase the specific surface area of the carrier. However, the inner surface area of ceramics is still too small, so it is necessary to apply materials with larger surface area, such as alumina coating, in the nest room.
The ternary catalytic converter mainly includes catalyst, carrier and coating. (photo Source: DOI:10.1016 / S0920-5861 (02) 00384 MuthX) so far, platinum group metals (active components), carrier and coating constitute the basic ternary catalyst. If the catalyst is protected by a metal shell and some small parts such as gaskets and interlayers are added to it, a ternary catalytic converter is obtained.
Stealing catalytic converters = stealing precious metals we can see that for ternary catalytic converters, the most important component is platinum group metals, but their content in the earth's crust is very low, so the output is also very low. According to statistics, in 2019, the global production of rhodium was less than 24 tons, compared with 3300 tons of gold, which is also a precious metal.
Low production naturally brings high prices. On December 27, 2021, the prices of rhodium, palladium, platinum and gold per gram are about RMB 4150, 553,175 and 364 yuan respectively-one gram of rhodium is more expensive than 11 grams of gold. No wonder thieves pry away the ternary catalytic converters of the car chassis before midnight, which contain substances that are more expensive than gold. Ternary catalytic converters of different models are worth thousands of yuan, and some even cost tens of thousands of yuan.
Precious metals. (photo source: Alesia Kozik / pexels) in addition, since the implementation of the sixth National vehicle Emission Standard in July 2020, both gasoline and diesel vehicles have to add catalytic converters, so more precious metal catalysts are needed. If there is no timely supply, the prices of palladium and rhodium may continue to increase.
The price of palladium surpassed that of platinum for the second time in 2018 (for the first time in history around 2000) and has since far exceeded the price of platinum. At present, it is still controversial whether to replace palladium in gasoline vehicles with platinum again, and more manufacturers of catalytic converters are still in the wait-and-see stage, because the palladium-based catalyst technology in gasoline vehicles is very mature. More money is needed to redevelop platinum-based catalysts.
Internal combustion engine vs motor is not only the cost of catalyst is troubling the manufacturers of catalytic converters, the re-emergence of the electric vehicle industry has also made these "big companies" feel the crisis, because electric vehicles will no longer need three-way catalytic converters.
Recently, the German company BASF issued a statement that it wants to separate the business related to the ternary catalyst and exist as an independent entity. Some analysts believe that this move is ultimately to sell and transfer the affiliated entity, that is, to plan to cut off this piece of meat that is no longer "fat".
Faraday electrolysis experiment. (photo: SHEILA TERRY / SCIENCE PHOTO LIBRARY) Johnson Matthey, a British company with ternary catalytic converters as its main source of income, has adopted a completely different strategy. They said they would continue to make ternary catalytic converters, but would also expand their businesses related to green hydrogen and proton exchange membrane fuel cells.
It is not easy to completely replace the internal combustion engine. Now, some scientists are trying to improve various technologies to improve the ability of catalytic converters to deal with automobile exhaust, while others are working on developing electric vehicles powered by lithium-ion batteries or fuel cells. For these electric cars, at least they no longer have to worry about catalytic converters being stolen.
Reference link:
Https://knowablemagazine.org/article/society/2021/why-do-thieves-keep-stealing-catalytic-converters-its-elemental?
Utm_source=email&utm_medium=knowable-newsletter&utm_campaign=K_newsletter_2021-12-12
Https://advancedfleetmanagementconsulting.com/eng/2020/10/11/three-way-auto-catalyst/
"Platinum 2004" from https://www.technology.matthey.com/
Https://www.kcet.org/socal-focus/breathe-deep-and-then-thank-the-epa-that-you-can
Https://www.kcet.org/history-society/how-los-angeles-began-to-put-its-smoggy-days-behind
Https://doi.org/10.1016/S0021-9517(02)00067-2
Https://doi.org/10.1016/S0920-5861(02)00384-X
Http://www.tanxshu.net/xiangqing/19463.html
This article comes from the official account of Wechat: global Science (ID:huanqiukexue), written by Wang Yibo, Wang Yibo
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