Transit Brussels-Beijing-Tokyo

Hello,
I am a Belgian national and will be travelling with two minors from Brussels to Tokyo with transit in PEK (Beijing Airport) with the same airline (Hainan). My transit is 2h and I do not need to change terminal (it is T2-T2).
Please let me know whether I need to pass through immigration/customs in Beijing or I can stay in the transit area ? Do I need to apply for 24-hour visa-free transit ?
And what happens to my checked-in luggage? Can it be registered directly until Tokyo or I have to collect it in Beijing? Thanks !