For better or for worse, there will be no independent Catalonia in the foreseeable future. About 40-50% of Catalans don't support this. The EU doesn't support this, no Western nation supports this (save maybe Russia if you consider them Western -- and even their position is unclear). Furthermore, Spain won't allow it, and they're the main actor in a position to do something about it.
Even if Catalonia somehow manages to enforce its declaration, the economic consequences will be so devastating that they will reverse course in due time.
Even if Catalonia somehow manages to enforce its declaration, the economic consequences will be so devastating that they will reverse course in due time.