I hold a Nepali passport. Do I need transit visa if I am transiting via Beijing for 23hrs & 20 min?

Hi - I am a US permanent resident and hold a Nepali passport. I will be in transit in Beijing for 23 hrs and 20 mins (arrive 6:40pm and depart 6pm next day) before my flight to Thailand. Do I need to get a transit entry permit? Also, can i leave the airport for 1 night? Appreciate a prompt response as I have my flights booked but no entry permit yet and dont have time to apply for an entry permit. Thanks