There doesn't need to be. Just perform a search! When you visit a user's profile, the search box is automatically pre-filled with their user ID number. All you have to do is append a small snippet, and you can see all their questions which either have or do not have an accepted answer.
So, just click in the search box and add in
hasaccepted:1 (or you can use 0 to find questions which don't have an accepted answer) and commence your search!
Visit the search options help page for details on more advanced searching. Useful here:
hasaccepted:0 - questions which do not have an accepted answer
answers:0 - questions which have no answers to them yet