Published in “Nature communications” (Online Publication, July 15, 2023).

Single-atom catalysts dispersed on support materials show excellent heterogeneous catalytic properties that can be tuned using the interactions between the single atoms and the support. Such interactions depend on whether the single atoms are located on the surface or within the interior of the support. However, little is known about immobilizing single atoms on the surface or within the interior of supports deliberately and selectively.

We achieved such location-selective placement of single atoms through the choice of metal complex precursor, solvent, and workup procedure. Using CdSe nanoplatelets as a support, a cis-[PtCl₂(dmso)₂] (dmso: dimethyl sulfoxide) precursor in an aprotic solvent exclusively attaches single Pt atoms on the surface of the support. In contrast, a [PtCl₄]²⁻ precursor in a protic solvent followed by amine treatment places 60% of the single Pt atoms inside the support by cation substitution. The surface-adsorbed single Pt atoms show higher stability in photocatalytic hydrogen evolution than the substituted ones, and the preclusion of substitution as internal Pt maximizes the activity.

This study demonstrates that the location of single-atom catalysts with respect to their support is an important factor to the catalytic properties. At the same time, we have devised using coordination chemistry a new method to immobilize single atoms to a support location-selectively. These insights would be useful in understanding and development of various single atom catalysts.

Endo, K.; Saruyama, M.; Teranishi, T., Location-Selective Immobilization of Single-Atom Catalysts on the Surface or Within the Interior of Ionic Nanocrystals Using Coordination Chemistry, Nat. Commun., DOI : 10.1038/s41467-023-40003-8 (2023).