Can PhD students patent their work
There is no generic rule that PhD students can't patent their work. When they do, usually, the university or research institution has rules about who owns the IP of what's being done in their labs. My alma mater had a 3-thirds rule where the student, the supervisor and the institution all held a third of the IP.
I don't find it particularly surprising that only few students end up patenting their work. Patents are much less useful than good scientific publications when applying for academic positions or grants. It seems normal that the focus is set on the later.
Also relevant: patenting costs money to file and money to maintain. It only makes sense to secure future sales. Students rarely have the funds for this and institutions usually prefer to spend on other things more closely related to their mission. Most of the time the decision not to patent is motivated by the low potential gain vs. costs ratio.
Universities are usually a bit generous in what they accept to file, but then eventually drop the payments later on if it's evident that the work does not bring any profit.
This will likely vary from university to university. At Carnegie Mellon University it is very common for students (and professors) to patent their work. I suggest you talk to your department chair about how the university handles intellectual property. For what it's worth, you may be able to find information online (e.g., CMU's IP guidelines are online).
No advice on 'yes go patent it' or 'don't patent it' will suit your case.
Couple of points to think about:
Location: Country, and then university and department you are in.
Funding: Are you fully funded by the university, is there any clause in your contract about this?
- Supervision: What your supervisor(s) wants/recommends. Maybe he/she is more like to publish journals instead of dealing with patents. Maybe he/she likes the idea and supports you on this. You need to discuss this with him/her.
- Publications: Your previous publications, are they part of your patents? When did you submit them; and so on.
- IP Department: The group/department that deals with intellectual property. If your university does not have it, then can you afford a lawyer/firm to do that?
- Waiting time: How many years you have to spend to see if the patent goes through.
- Ph.D Defense: How do you defend your thesis if no publication and the best case scenario 'patent pending' situation.
So best advice would be to think about those points and talk to someone at your university that deals with IP submissions.