With all of the technological advances lately, couldn’t a catalytic converter be designed with cheaper materials that aren’t worth stealing?
Catalytic converters process hot exhaust gases. Common metals oxidize readily at these temperatures, so they don’t last very long. Only rare metals will survive long enough to be worth building into the exhaust system.
Not yet. Electrics cars are really the answer here. Nothing to catalyze because there are no emissions.
Replacing the metals in catalytic converters is a lot easier said than done. We use those metals in catalytic converters because of the unique chemistry properties of the platinum group, which has 6 metals in it (ruthenium, rhodium, palladium, osmium, iridium, and platinum). We chemists call this group of metals the noble metals because of they are highly non-reactive, which is a result of their electron configuration. As you may remember, the electron configuration is a large part of what makes an element distinct from the other elements on the periodic table (pedants: yes this is a simplification for ELI5). So, in short, simply choosing a cheaper catalyst isn’t exactly easy (or even necessarily possible).
The noble metals have tons is applications for being a useful catalyst, including in spaceflight! Hydrogen peroxide is used as a single fuel for rockets by flowing it over a noble metal catalyst bed, causing it to spontaneously decay into water and oxygen gas. This reaction propels the rocket without the need for a second oxidizer!
Edit: thanks to u/justonemom14 for pointing out the obvious mistake I made!
I believe there are only 7 known metals that can be used in catalytic converters. They need special properties to convert exhaust to less harmful gases.
You could easily create a converter that is less valuable to theft by making it more difficult and costly to recycle, but theft isn’t enough of a problem that it is worth intentionally making them more difficult to recycle.
That being said, maybe after he is done revolutionizing modern technology once again, John Goodenough (the rockstar of material sciences) might dedicate half a afternoon to creating a new renewable converter part with a 700 year part life.
*Could* one be designed? Perhaps. Chemistry’s a complicated subject.
*Has* one been designed without other downsides? Probably not. There’s no obvious reason why manufacturers would keep using a more expensive solution if a cheaper one were available.