Thank you for your good thought, me (engineer), my colleague (PHD in Chemistry) and guys from "Muséum national d'Histoire naturelle" needed your great experience with that kind of hornet.
We are putting some wax/honey cap from the extraction in our trap to lure them and it works fine.
We got some honey leak from a supper after a 40 degree C day cause we put the bee escape to empty it. There was like 10 hornets eating the honey from the side of the hive and none of them gave a damn about the bees. They eat the honey for themselves, they catch the bees for their colony and they seem to prefer the honey.