Do i need a visa transit of this?

i booked a flight through china southern airlines to go from Phnom penh to beijing a 3 hours and a half layover my next connection with china southern that take me from beijing to uramqi. at uramqi, i have another 16 hours befor flying back to Novosibirk with S7 air. in total, i am in china for less than 24 hours but i have never leave the airport in china. would i still need any sort of transit visa this?