The only hydraulic hammers that I have seen or have any experience with are the pile driver type use to drive posts/poles in the ground for fences, jetties, docks, and breakwater barriers. I think that the hammer may move to quick and the stroke won't be long enough to split the wood all the way through. It might work though, you never know until you try. I would look into a Splitfire 3 point hitch wood splitter.
The price is reasonable and the splitter works well.