文摘
A high tolerance to oxidation of Ru nanoparticles loaded on 12CaO·7Al2O3 (C12A7) was examined by in situ X-ray absorption fine structure (XAFS). Ru nanoparticles on electron-doped C12A7 (C12A7:e–) and stoichiometric C12A7 (C12A7:O2–) are robust to oxidation, while those on Al2O3 and on MgO with Cs promoters are easily oxidized. The oxidation tolerance is higher for Ru/C12A7:e– than Ru/C12A7:O2–. The main factor of the oxidation tolerance comes from the electron donation property of C12A7:e–. C12A7:e– is an electride in which electrons serve as anions, and these anionic electrons with a low work function (2.4 eV) have a high ability to donate electrons to supporting Ru nanoparticles with a higher work function (4.7 eV). Electron transfer from C12A7:e– maintains Ru nanoparticles in the metallic state even under oxidation condition. The Ru catalysts on C12A7:e– with high oxidation tolerance can be applied to various catalytic reactions under oxygen-rich conditions, in which conventional catalysts are rapidly oxidized.