Hi,

As a general principle, you should devise a recovery protocol for your photocatalyst and integrate the recyclability assessment with a catalyst stability analysis (chemical and /or morphological). Assuming your photocatalyst is solid or in colloidal suspension, you should probably opt for a physical method, such as filtration and/or centrifugation, or even dialysis in the case of very stable colloidal suspensions; chemical methods such as solvent extraction are more suited for homogeneous catalysts, but anyway the choice is highly dependent on the kind of system you are dealing with.

After recovery, you should 1) characterize your spent catalyst in detail, to assess its stability and 2) subject the spent catalyst to an identical catalytic run. You can then decide whether to report distinct* or cumulative performance indicators (e.g. turnover number) for the two runs. Both information at points 1) and 2) combined will give you overall information about the recyclability.

If you are working with an immobilized catalyst, such as on the walls of a flow photoreactor, you may need to devise a regeneration/reconditioning protocol, for example an eluent mixture to flow through your catalyst film, and then directly proceed to a new catalytic run. Stability assessment in this case would be done mainly by assessing the decrease of the catalyst performance over time, since identifying the decomposition traces of the catalyst in the effluents would be more challenging than when the catalyst is in suspension, and not immobilized.

Hope you may find this useful! Good luck

If you want advice on how to recycle the XY molecule, you must state its structure, or other known characteristics.