Not really, "schemas" as such don't really exist in informix in that way - the closest thing to schemas is the owner of the tables/synonyms/functions/etc - and a lot of abstraction tools (Java in particular) regard ownership as schema.

You could get a list of table names/schemas and suchlike out of systables, eg...

select tabname
from systables
where owner = ?
and tabtype = "T"
and tabid > 99
-- Use each result to create a 'drop table ?'
;
select tabname
from systables
where owner = ?
and tabtype = "S"
and tabid > 99
-- use each result to create a 'drop synonym ?'
;
select tabname
from systables
where owner = ?
and tabtype = "V"
and tabid > 99
-- use each result to create a 'drop view ?'
;