If you are looking to silence notification sounds, you can use Volume Widget. It allows you to manually change to different sound profiles. I have a profile where notification sounds are turned off. I set this when I go to bed. When I wake up, I change it back to my regular sound profile with notification sounds turned on. Volume Widget requires you to tap on the widget to change sound profiles. It does not do it on a timer. Also, notifications do come through. They just won't make a sound.
I personally, do not use my personal phone while I'm at work. I just set it to airplane mode when I get to work. I take it off airplane mode when I leave work.