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.