Carbothermal reduction assisted by hydrogenation treatment for preparing single-phase CeC2 nanoscale powders

Abstract

Single-phase CeC2 powders can be successfully prepared through the carbothermal reduction assisted by hydrogenation treatment (CRHT) using 20–50 nm CeO2 as cerium source and 100–200 nm carbon black as carbon source. During the hydrogenation process, the interaction of CeO2 with H2 leads to a partial valence reduction of Ce ions, yielding a partially anoxic phase (CeO1.675) and a hydrogenated phase (CeH2). CeO1.675 can increase the oxygen vacancies required in the reaction process, while CeH2 can produce gas-phase reductant H2 at the reaction temperature, which together promotes the reduction reaction. The results show that the CRHT can obtain single-phase CeC2 powders at a temperature of 1550 °C, which is 100 °C lower than its theoretical temperature. For the preparation of CeC2 powders, the CRHT is a low-temperature and efficient method.