how do you plan to "split" it?? you'd have to make the divider permanent and 100% ABSOLUTLY ESCAPE PROOF; sealed with something strong.
honestly, for peace of mind, just get two enclosures. you only benefit yourself with one modified enclosure, and that is not what keeping animals about.
besides the risk of escape/getting to the other side, an enclosure like this does not support the quarantine process for new reptiles with other reptiles in the home.
all this + itd be practically impossible to find a proper lid for this tank. also keeping temp gradients would probably be pretty hard.