Leaving Bejing Airport for 13 hour layover

On our return trip from Thailand back to home (USA), we have about a 12 hour layover at the Bejing airport. We land at 1am on April 5th and leave Bejing at 1pm on April 5th. We want to get a hotel room and enjoy some sites during our layover. Can we just leave the Bejing airport, go to the hotel, see some sites, and return to the airport to fly back to the US? Or is a visa required? Anything else we should know? Thank you.