Can smelly car exhaust be made “cleaner”?

Too many cars on the road will not only cause traffic congestion, but also pollute the environment, especially the exhaust gas, which is really smelly.

Of course, exhaust gas is unfairly blamed because it is related to the fuel that the car "drinks".

Fuel is like a functional drink for a car. With it, the car can run, but it also emits exhaust pollutants.

Image source: pixabay

These pollutants not only smell bad, but also harm people's health. When they spread into the atmosphere, they are more likely to produce smog, acid rain, etc. Therefore, we need to find a way to make them "clean" before leaving the car.

Scientists have come up with a solution. They take advantage of the "mutual promotion and restraint" relationship between pollutants to "transform" pollutants such as carbon monoxide, nitrogen oxides, and hydrocarbons into colorless, odorless, and non-toxic water, nitrogen, and carbon dioxide.

However, such a transformation requires the help of "precious metal catalysts" to achieve.

So, can automobile exhaust become “cleaner” as long as there is a precious metal catalyst?

Not enough!

In Romance of the Three Kingdoms, Liu Bei is the commander-in-chief of the Shu army, but he cannot do without his brilliant military advisor Zhuge Liang when deploying his troops and making strategic plans.

The same is true for solving the problem of automobile exhaust. The "commander-in-chief" cannot do without the "military advisor", and without the assistance of the "military advisor" of "oxygen storage materials", precious metal catalysts will be helpless.

Cars start and stop, and sometimes there is too much oxygen in the exhaust gas, so nitrogen oxides will hold on to the oxygen and "lie flat" without moving; sometimes there is too little oxygen, so carbon monoxide and hydrocarbons will complain about being "not full and hungry" and "play tricks" on the spot.

Thanks to the existence of oxygen storage materials. When there is an excess of oxygen, this resourceful "military advisor" will use its crystal structure like the "Eight Diagrams Formation" to lock up some of the oxygen, and then release it when oxygen is needed. In this way, the whole process will not be troubled by the "military supplies" that are sometimes more or less.

What is this ingenious oxygen storage material made of? The answer is cerium dioxide.

Cerium in cerium dioxide is a type of rare earth. Rare earth is a strategic resource in China, and cerium is the type of rare earth ore with the largest reserves in China.

Unfortunately, in the 1970s, China was unable to refine high-purity rare earth products due to its lagging technology and had to export rare earth ores at low prices and then buy purified products from abroad at dozens or even hundreds of times the price.

This is definitely a bad deal!

Can we buy foreign technology? Unexpectedly, the other party not only offered a sky-high price, but also required us not to sell the purified products ourselves, but to let them handle it.

It’s so frustrating!

"We must do our own research and development, and do better than them to bring honor to the country!" After learning about this situation, Xu Guangxian, who was over 50 years old at the time, resolutely decided to change the direction of scientific research and was determined to crack the "code" of rare earth separation and purification.

However, this "password" is not so easy to crack, but Xu Guangxian only said: "No matter how difficult it is, we must do it!"

In order to crack the "code", he consulted a large number of documents, made tens of thousands of document cards, and repeatedly and in-depth analyzed, summarized and concluded... Three years later, Xu Guangxian led the team and finally found the key to unlock the "code" and creatively proposed the "cascade extraction theory"!

Although there has been a major breakthrough in theory, how can we actually achieve large-scale production? Can we really solve this global problem?

Everyone felt that in order to find a basis for combining actual production with theory, Xu Guangxian had become "obsessed".

For a long time, he was silent and deep in thought. He had no holidays or weekends and worked more than 80 hours a week. He spent the day in the laboratory doing experiments and the night pondering the experimental results and technical problems.

Colleagues in the factory and laboratory joked: "We follow Teacher Xu, we are manual laborers during the day and mental laborers at night."

Xu Guangxian and his team created the "one-step amplification of rare earth extraction and separation process" technology, making the originally very complicated production process "idiot-proof".

In other words, by putting in rare earth raw materials, various high-purity rare earth products can be continuously produced on the other side. This world-class problem was solved in one fell swoop!

In order to promote the new technology, Xu Guangxian opened a "cascade extraction" workshop across the country and contributed his scientific research results for free. This rare earth separation technology, which was considered top secret abroad, suddenly became a process that many township enterprises could master. China became a major producer and exporter of rare earths, and the pattern of the international rare earth industry changed.

Since then, as scientists have continuously overcome difficulties, advanced domestic oxygen storage materials have finally become the most reliable "military advisor". With the help of the "military advisor", exhaust gas can finally come out of the car cleanly!

I believe that in the near future, with the continuous advancement of technology, we will be able to find more convenient and lower-cost ways to completely transform car exhaust into a fresh breath of nature!

Source: Chongqing Industry-University-Research Cooperation Promotion Association

Author: Pan Fusheng, Academician of the Chinese Academy of Engineering, Professor of Chongqing University, Chairman of Chongqing Association for Science and Technology

Review expert: Mao Yi, chief expert of Chongqing Science Communication Expert Group, professor of Chongqing Electronic Engineering Vocational College

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