There are a few things to consider here. You may need to dig in to the Elisp Manual (C-h i to get to the available manuals...) because there are some key concepts about functions, arguments, and commands that you may not be familiar with.
First of all, as @lawlist noted in the comments you want to to use the help system and/or source code to understand what arguments are required for the functions you are calling. C-h f origami-open-node will give you the function's doc string, which shows that it expects BUFFER and POINT to be passed as arguments.
Looking at the source (follow the link from the Help buffer) and you'll see that
origami-open-node has an
(interactive ...) form. This specifies how the arguments are obtained when the command is called interactively (when you call it with a key binding or via M-x). But when calling the same function from lisp you need to pass in the arguments yourself, or indicate that you want the interactive behavior by using e.g.
The next question is how to get the command to do two different things. As you've defined it so far (ignoring the missing arguments), your command would open and then close the node -- I suspect that is not what you want. It sounds like to want to toggle the node open or closed depending on its current state. That would require something like an
(if ...) form and a way to check whether the current node is open or closed, which might require more digging in to how origami mode works.
All that said, I think what you want is already provided by origami: have you tried the command
origami-toggle-node? Looks like origami does not bind any keys by default but provides a mode map, so you can use:
(define-key origami-mode-map (kbd "C-c C-f") 'origami-toggle-node)