A 45mm f4 on Pentax 67, or 17-40 on 35mm (17mm with very strong lead-in foreground anchor).
I don't actually shoot sunrise or sunsets (stopped that years ago), but the foreglow and afterglow of the event, that is to say, the camera has its back to the Sun.
The super-wide angles (17mm and lower) are good if have a sweeping, detail-rich landscape, quite aside from the Sun e.g. a beach with striking rock formations, backlit clouds on the horizon and the Sun placed somewhere in balance. But in 35mm, the wider you go, the further and further scenic content is pushed back. Probably better to stick with medium format and fit the scene to that frame. Personal choice.