Embedded MoN@C nanocomposites as an advanced catalyst for ammonia decomposition to COx-free hydrogen

s Mo-based nanoparticles (MoO 2 and Mo 2 C) embedded in porous carbon matrix have been synthesized by a successive hydrothermal and thermal treatment strategy. The synthesized materials were tested for CO x -free H 2 production via ammonia decomposition . Various characterizations, including N 2 -sorption, TGA , FTIR, TEM, XRD , EDX and XPS, were employed to investigate the morphology, component and structure of fresh and used catalysts. In terms of fresh Mo@C sample, tiny Mo-based nanoparticles (3–6 nm) are homogeneously dispersed in porous carbon matrixes, which were rapidly nitridized to MoN phases during reaction process. Most of MoN species were still embedded in carbon matrixes after 25 h stability test. For comparison, MoN@C sample was achieved via temperature-programmed ammonolysis of Mo@C sample, demonstrating the formation of MoN species and enhanced activities. The ammonia decomposition activity (∼90% conversion) is obtained over MoN@C catalyst at 600 °C and 15,000 h −1 , which is higher than that of non-pretreated Mo@C catalyst. This embedded structure also endows them with a relatively stable performance even at high temperature.