Would Avada Kedavra Work on Voldemort?

You can absolutely "kill" him in a duel, but now that the Death Eaters know that there are ways of creating new bodies and that Voldemort can't be fully killed, it wouldn't delay his return to power like it did the first time.

Does Harry Potter use Avada Kedavra on Voldemort?

Avada Kedavra was Lord Voldemort's signature spell. In fact, the Dark Lord directly killed multiple notable figures, including Lily and James Potter, with the Killing Curse. ... By the time he faced Harry in their final duel, both wizards could have used the Killing Curse.

Does Avada Kedavra work on Horcruxes?

Avada Kedavra kills. Horcruxes are the opposite of a human being, so foremost they can't be killed as that's a rather obvious fact about humans.