A Discovery of Strong Metal-Support Interaction (SMSI)Between Platinum Group Metals & Hydroxyapatite

Recently, MEDC discovered O-SMSI between platinum group metals (Pt and Pd, PGMs) and hydroxyapatite (HAP) under oxidative atmosphere. The results have been published in the Journal of Chemical Science (Chem. Sci., 2018, 9, 6679 - 6684).

SMSI was coined by Tauster et al. in 1978 and now referred as classical SMSI. Since its discovery, it is mainly focused on the PGMs catalysts supported on reducible metal oxides, and its reaction conditions are also limited to high temperature or ultra-high vacuum conditions for causing carrier reduction. SMSI can change the morphology and electronic property of metal nanoparticles, thus after the reactivity and selectivity, which are of important effect on the catalytic performance of supported catalyst. Also, it can generally stabilize the metal particles with embedding metal particles on the carriers, therewith stable metal catalysts can be prepared easily.

Schematic diagram on the development of SMSI researches

(Image by TANG Hailian and QIAO Botao)

In previous studies, MEDC firstly discovered the O-SMSI between Au and HAP under oxidative atmosphere based upon research experience of HAP supported metal catalysts. They designed and developed highly active & stable Au/HAP-TiO2 catalysts with unique semi-encapsulated nanostructure through tuning the O-SMSI, and systematically investigated classical SMSI of oxide supported gold catalysts.

This time, PGMs nanoparticles were encapsulated by HAP carrier-like thin layer, and their aggregation growth and leaching among reaction process were effectively inhibited. Therefore, the reusability and reaction stability of the HAP-supported PGMs catalysts were markedly improved. Consequently, the O-SMSI existed between PGMs & HAP was discovered. This discovery identifies firstly that O-SMSI can occur in the PGMs catalysts, which provides a new way for the design and development of stable PGMs catalysts under oxidative environment.

This research work was financially supported by the National Natural Science Foundation of China, the Ministry of Science and Technology & the Chinese Academy of Sciences. (Text by TANG Hailian, QIAO Botao and Lucy)