I would absolutely turn that little room into a pantry! If you really like the little pantry you are using now, you can hang a broom and dustpan behind the door in the little room.

I can't tell for sure how big the empty room is, but I'd put 18" shelves on the back wall for bulk items and small appliances, and 12" shelves on the right for food. Ideally the shelves will be adjustable.

Of course you know best what your storage needs are.

I would add shelves all around except one side, use the shelves vertical wise for storage of all your appliances such as slow cooker, pressure cooker, food processor etc. and the side and lower areas for vacuum, cleaning supplies etc. .