Hi there!
Which library are you using? If the official Neo4j Driver for Python (Bolt), I think it is correct that Nodes are not JSON serializable. You can retrieve the properties and labels from the Node (https://neo4j.com/docs/api/python-driver/current/types/graph.html) and then build up a standard list/dict and convert that to JSON with json.dumps().
Hope that helps!
Cheers,
-Ryan