Carbon-supported cobalt catalyst for ammonia synthesis: Effect of preparation procedure

Supported cobalt catalysts were synthesised, characterised (by H2 TPD, XRD, TEM), and tested in ammonia synthesis at 9.0 MPa (400–470 °C; H2:N2 = 3:1). Partly graphitised carbon of high surface area (840 m2/g), cobalt nitrate, and barium nitrate were used as a support, a precursor of the active phase, and a promoter precursor, respectively. Both cobalt dispersion in the Ba-doped catalyst and, to a greater extent, catalytic properties of the promoted Co surfaces (TOF) proved to be dependent on the unpromoted material pretreatment (reduction in H2, subsequent calcination in air). The kinetic studies of NH3 synthesis have shown explicitly that Ba-promoted cobalt on carbon is very active and less inhibited by the ammonia product than the commercial magnetite-based material.