Solid Single-Atom Catalysts in Tandem Catalysis: Lookout, Opportunities and Challenges.

Tandem catalysis stands out as a major instrument towards the intensification of existing and future chemical processes. Initially formulated in the field of homogeneous catalysis, the concept relies on the single-pot integration of two (or more) catalysts showing high specificity for mechanistically decoupled reactions, while being operational and compatible under a single set of operation conditions. Isolated metal atoms stabilized on solid carriers in single-atom catalysts (SACs) hold the potential to reconcile the high reaction specificities of mononuclear sites in molecular catalysts with an intrinsic catalyst compartmentalization on inorganic matrices. Understandably, SACs have started to be considered as platforms in tandem catalysis. Tandem (electro)catalytic processes based on SACs have been showcased recently. While this sets excellent prospects for the expansion of this research subarea, challenges are faced, particularly as to the verification of the tandem nature of the processes.