COx free hydrogen production over cobalt incorporated silicate structured mesoporous catalysts

On board hydrogen production for fuel-cell derived motor vehicles requires resources for COx free hydrogen production. Ammonia is one of the most attractive hydrogen storage compounds which may yield clean hydrogen through catalytic decomposition. In the present study, new cobalt incorporated mesoporous silicate catalysts were prepared for ammonia decomposition, by applying a one-pot hydrothermal synthesis procedure. Ammonia decomposition experiments were performed in a fixed bed flow reactor in a temperature range of 400–750 °C. While all of the synthesized catalysts showed good activity in hydrogen production from ammonia at temperatures higher than 500 °C and at a space velocity of 150,000 h−1, catalysts prepared with KOH promoter gave the highest activity with 70% conversion at 600 °C and close to total conversion at 700 °C. Reduction temperature and period of the synthesized catalysts were also shown to be highly effective on the catalytic performance of the synthesized materials.

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► Synthesis solution pH had significant effects on the structure of the final product.
► KOH greatly enhanced the incorporation of cobalt into the mesoporous lattice of amorphous silica.
► Catalysts prepared with KOH promoter gave the highest activity with 70% conversion at 600 °C.
► Ammonia conversion was increased by increasing the space velocity over the same catalyst.
► The texture and porosity of SiO2 is associated to the availability of Co species that affect activity.