DB_OWNER permissions for user I would like to know if db_owner can change the recovery model of database.

Using TSQL-   alter database db set recovery simple
Well , its simple from the word itself db_owner:


  Members of the db_owner fixed database role can perform all
  configuration and maintenance activities on the database, and can also
  drop the database.


So yes , user with db_owner role can change the recovery model.

Also, for complete understanding please read Database-Level Roles