Preparation and X-ray photoelectron spectroscopic characterization of Sn-doped C12A7:e− electride nanoparticles

Abstract

Understanding the chemistry of dopants in electride nanoparticles is essential and challenging owing to the active nature of the electride and the low atomic concentration of the dopants. In this work, we developed conductive Sn-doped C12A7:e− electride nanoparticles by a modified sol-gel method, and performed a comprehensive X-ray photoelectron spectroscopic characterization on the surface chemistry of the doped electride nanoparticles. The resulting electride Ca12Al(14−x)Snx:e− (x = 1) exhibited an electron concentration of 1.65 × 1021 cm−3 and a specific area of 53.9 m2/g. XPS results showed that Sn was in the form of Sn4+ at the surface of the doped C12A7:e− nanoparticles. The depth distribution of elements was investigated by XPS Ar+ ion and Ar cluster ion sputtering. Results showed that Sn was enriched at the surface and sputtering partially reduced Sn4+ to metallic Sn, and Ar cluster ion sputtering showed much weaker effect on the reduction of Sn4+ than the Ar+ ion sputtering. The chemical states and distribution of elements Ca, Al, O did not show obvious change after sputtering. The present study provides novel insights on the chemical states analysis of doped-C12A7:e− nanoparticles.