Yes a clogged catalytic converter can be a cause of rough engine idle.
When the catalytic converter becomes clogged it restricts the airflow for the exhaust which then creates back pressure on the engine and that leads to rough idle.
You can start the vehicle and have someone press on the gas pedal to accelerate the engine as you hold your hand over the tail pipe and see if you get enough pressure coming out of the exhaust.
If the exhaust seems restricted then your catalytic converter could be clogged and need either removed or replaced.
In the place I live in I just had my catalytic converter removed and my engine performed much better.
Replacing a catalytic converter is expensive so unless you really have to have the catalytic converter on the vehicle the best thing to do is just have the catalytic converter removed from the vehicle.
Some other things besides a catalytic converter that can cause rough engine idle are bad spark plugs, bad spark plug wires, low fuel pressure, clogged or dirty fuel injectors, bad ignition coil, bad distributor cap or rotor or even a clogged or partially clogged fuel filter.
Check to make sure you're getting enough fuel pressure to the engine otherwise it will not run correctly.
You can have a shop put a fuel pressure tester on the fuel line to test for the proper amount of fuel pressure.