Insight into the nature of Au-Au2O3 functionalized palygorskite

Abstract The Au/palygorskite (Au/Pal) composite was prepared via supporting gold species on the surface of palygorskite. Results indicated that the dehydration of palygorskite showed obvious effect on the Au 0 /Au 3 + molar ratio, and the generated hydroxide radicals (− OH) played a special role in the formation of Au-Au 2 O 3 coexistence system. Au 2 O 3 nanoparticles were formed on the hydrated (010) palygroskite surface, while Au nanoparticles were mainly on the surface of unhydrated (100) palygroskite. The decomposition of Au 2 O 3 to metallic Au was promoted by increasing calcination temperature. However, this process would be hindered by –OH radicals produced at high temperature. The Au 0 /Au 3 + molar ratio changed nonlinearly with the calcination temperature. The dehydration was beneficial to the formation of the chemical bonds between Au species and palygroskite. Au-Au 2 O 3 coexistence expanded the application of gold supported composites. Atomic-level interfaces between Au species and palygorskite surface were also investigated. Realizing Au-Au 2 O 3 coexistence by dehydration of palygorskite could provide a novel method for the synthesis of advanced mineral-based composites.