New semi trucks have two catalytic converters.
One is called a DOC or a Diesel Oxidizing Catalyst and the other is called a SCR or a Secondary Catalyst Reduction. The DOC captures the soot from the engine and then burns the soot off. The SCR converts the NOx emissions to N. So yes, newer big rigs have catalytic converters.
The next time you see a new big rig running down the highway, look and you won’t see the chrome stacks pointing up from behind cab.
Tester