(468e) Method to Produce High Densities of Isolated Atoms Regardless of the Support Functional Groups

Single-atom catalysts (SACs) with the advantages of both homogeneous and heterogeneous catalysts have been rising as a new frontier in the field of catalysis. Considering the host materials having similar functions to ligands in homogeneous catalysis, the robust nature and recovery of the heterogeneous catalysts make them very attractive. A large number of synthesis methods resulting in a varied population of atomic species have been developed, but a facile targeted synthesis of isolated metal atoms remained a challenge. Usually, the current synthesis methods are based on the functional groups and defects on the surface of the support.

We developed a simple general method applied to metals to synthesize single atoms with high density regardless of the functional group on the support surface. The technique overcomes the preparation challenges of SACs, such as high densities of the single atoms, and increases the active sites' stability. The method is based on the chelate fixation (CheFi) of precursors on the support surface before thermal treatment. In case of having a maximum density of the single atoms, one monolayer of precursors and then chelate fixation of the precursors with a chelating agent with a higher boiling point of the activation temperature of the catalyst. One of the essential advantages of this method is the independence of the functional groups on the support. We have enough evidence on diamond with no functional group that we successfully deposited single Pt atoms. In addition, several supports were used to produce SACs, including Volcane-XC-72, Al­₂O₃, SiO₂, and TiO₂. The representative image shows STEM images of 0.97% Pt/Diamond and 3.5% Pt on VXC-72 plus in situ XPS/CO temperature-programmed desorption for samples treated at different activation temperatures of 170°C and 300°C.