After working tirelessly with your graduate student to carry out a research and making serous input in a journal article involving both of you., who should be the first author of this publication?
The person who has the highest contribution to the research should be the first author. That means the person who had highest contribution in designing the study, conducting the experiments, data analysis and writing the manuscript.
After the first author, the rest of the authors are usually listed according to their contribution to the study.
I also think it is the graduate student because that is supposed to be his work that serves as his contribution to be conferred a degree. After all he is the author of the thésis and by that the author of any manuscript from the thésis Under the guidance of supervisors.
In some institution, student are required to present at least three published papers from their thésis as first authors in order to graduate from the institution.
To cater for this issue, some scholar classify authors using the first and last author system where by the first author is the main investigator (usually graduate student) and the last authors are generally known as the head of the lab or professors Under which the study was carried out.
So, I think in this case you can be the last author and enjoy the prestige of being the lab head or professor.
However, if your interest is promotion, you may need to undertake a different personal research, get it funded and engage interested student