24 hour transit without visa - for Malaysian

I am a Malaysian and bought a flight from Singapore - Beijing ( transit 3 hours) - Ulaanbaatar
Ulaanbaatar - Beijing (transit 6 hours) - Singapore
Do I need to apply for any sort of visa for my transit in Beijing for the above 2 flights. Will just hang in the airport and won’t be going out of the immigration. Appreciate your advice thank you in advance.