Welcome to genvibe
I don't see where the pulley is available separate from the rest of the tensioner assembly, but that doesn't mean it isn't.
Also, I can't say how hard it would be to replace the whole tensioner compared to replacing just the pulley, if you can find one
If you decide to go for the full tensioner, first you'll want to confirm this info before you spend any money

:
https://parts.toyotasouth.com/oem-parts ... dhcw%3D%3D seems to say that the Toyo0ta part number for a 2010 Matrix with 2.4L engine is 16620-0H021 which I think fits your 2010 2.4L Vibe. There's one on amazon for $27 US + tax at
https://www.amazon.com/ATPPCCE-Tensione ... B09YM22F6G.