The effect of acetic acid pretreatment for cobalt catalysts prepared from cobalt nitrate

The effects of acetic acid pretreatment for dried catalysts prepared from cobalt nitrate were investigated. Cobalt catalyst prepared from cobalt nitrate, followed by treatment of 2.2 M acetic acid, namely CoN/2.2Ac catalyst, showed the highest CO conversion as well as the lowest CO2 and CH4 selectivities in liquid-phase Fischer–Tropsch synthesis. On the contrary, cobalt catalyst prepared from cobalt acetate exhibited poor catalytic activity due to very low reduction degree of supported cobalt. The higher catalytic activity for CoN/2.2Ac catalyst could be ascribed to the formation of the mixture of cobalt nitrate and cobalt acetate with suitable ratio between them during acetic acid treatment, which led to an optimum balance between the dispersion and reduction degree of supported cobalt, eventually realizing the higher catalytic activity. Various catalysts were characterized by XRD, TPR and H2 chemisorption.