Hi Shirley, Welcome
At 6 months, your baby should be having longer awake times than that, more like 2hr45-3hr and be working on dropping that catnap. I'd say he's not sleeping more than 45min at naptime because he's not tired enough to take a good long nap.
At this age, its quite normal to have a night feed still. I'd try a BF at that 3am waking and see if he'll go to sleep a bit more easily and maybe even sleep a little longer in the morning.
Here's a suggested routine for a 6-month old:
7 - wake
10 - nap
11:30/12 - wake
2:30/3 - nap
4/4:30 - wake
7 - bedtime
I would suggest extending A times by 10-15min every few days though, rather than jumping straight to 3hr A time. If he's had an 11hr night, you can't really expect him to go back to sleep in the morning at this age. At 3 months, sure but at 6 months, an 11hr night is plenty, though 12hr is ideal, especially if he's at the younger end of 6 months and you're extending his A times.