Rapid selective detection of formaldehyde by hollow ZnSnO3 nanocages

► Hollow ZnSnO3 nanocages are successfully prepared. ► The hollow ZnSnO3 nanocages have high specific surface areas. ► The hollow ZnSnO3 nanocages show excellent gas-sensing properties. ► Such morphology renders ZnSnO3 promising for the development of formaldehyde sensors.