[en] In view of the High-Luminosity upgrade of the Large Hadron Collider (LHC) collimation system, a family of novel molybdenum-carbide graphite (MoGr) composites was developed to meet the challenging requirements of HL-LHC beam-halo collimation, in particular the electrical conductivity and thermo-mechanical performances. The Ultra-High Vacuum (UHV) behaviour of this material was extensively characterized to assess its compatibility with the accelerator’s specifications. The results presented in this paper correlate the outgassing behaviour with the microscopic features of MoGr compared to other graphite-based materials. Residual gas analysis (RGA) was exploited to optimize post-production treatments. (paper)