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

Abstract Single-phase CeC 2 powders can be successfully prepared through the carbothermal reduction assisted by hydrogenation treatment (CRHT) using 20–50 nm CeO 2 as cerium source and 100–200 nm carbon black as carbon source. During the hydrogenation process, the interaction of CeO 2 with H 2 leads to a partial valence reduction of Ce ions, yielding a partially anoxic phase (CeO 1.675 ) and a hydrogenated phase (CeH 2 ). CeO 1.675 can increase the oxygen vacancies required in the reaction process, while CeH 2 can produce gas-phase reductant H 2 at the reaction temperature, which together promotes the reduction reaction. The results show that the CRHT can obtain single-phase CeC 2 powders at a temperature of 1550 °C, which is 100 °C lower than its theoretical temperature. For the preparation of CeC 2 powders, the CRHT is a low-temperature and efficient method.