Maybe it cannot act as a direct catalyst for fusion but it could potentially act as a catalyst for another potential catalyst for fusion, such as a pellet of fissionable material.
Just re-read this and realized that I'm using the term catalyst in a way that would make a chemist eyes weep. These would be used up in the reaction so it's not a true catalyst but the term has been kind of co-opted to mean anything that can speed up the reaction of something.