The MPhil safety net

If you don’t yet have a contribution to knowledge that can be communicated in a PhD thesis, don’t despair. This might be because you are at an early stage in your research, still looking at the literature to find a suitable gap, or because your investigation hasn’t yet led to any conclusions. The latter case is easier since by this stage you should be fairly sure that the investigation will lead to conclusions that ought to be of interest. You supervisors will advise you what sort of conclusions will interest your academic audience: it is important to be guided by their advice.
But it does sometimes happen that a line of research leads nowhere, or simply rediscovers something that is already in the literature. This is not a source of any shame: discuss the problem openly with your supervisors. Maybe they can advise on an interesting change of direction, or an improvement to the investigative machinery you are using.
If not, then the options are to start again with a new problem, or to write up the research as an MPhil instead of PhD. MPhil is a perfectly respectable degree, and especially if your work has led to a useful overview of the literature, digest of existing theory, and description of the primary work that you have carried out, then simply submit it for MPhil.
How does the MPhil thesis differ from PhD? They both have an abstract, introduction, literature review, primary research, conclusions and suggestions for further work. The formal difference is in the primary research section. They both will give an account of the initial investigations into the research question posed in the Introduction. But the PhD thesis will then discuss the process of refinement identifying the contribution to knowledge, and the more detailed investigation that establishes this securely.
If your career is already beyond the PhD stage, and your research is for establishing a track record in an area that is new to you, it is unlikely that anything useful will be gained by attempting to publish results that don’t make a contribution to knowledge. Use the work in your lectures by all means, but don’t waste the time of reviewers and editors.