24 hour layover in Wuhan airprot, no visa where can we sleep?

First of all, don't worry about visa. You can enjoy the 24 hours visa free policy.
About the accommodation, there are only VIP Lounges at airport that only service for first-class cabin passengers and business class passengers. So you can find a hotel nearby the terminal building. But if you wanna go out of the airport, you need to apply for the Stay Permit at airport. Then you can allowed to go outside.
Airport Hotel is recommended. It has clean environment and kind service. The transportation to/from airport is quite convenient. It's just located at the left side of the terminal building. You can find it easily. You can take a shower and have some rest there.