Mild temperature hydrogen production by methane decomposition over cobalt catalysts prepared with different precipitating agents

摘要

Hydrogen production by methane decomposition has been studied using different cobalt catalysts obtained by reduction of cobalt oxide precursors synthesized in ethylene glycol and using three different precipitating agents: sodium carbonate, ammonium hydroxide and urea. The physicochemical properties of the catalysts precursors vary with the precipitating agent, which shows a significant influence in their catalytic performance. Thus, the catalysts obtained from precursors precipitated with Na_2CO_3 or CO(NH_2)_2 show remarkable catalytic activity at lower temperatures, which in both cases has been assigned to the lower particle size and aggregation degree of the final metallic Co phase. Accordingly, the use of urea as precipitating agent led to the catalyst with the highest H_2 production at 600℃ after 12 h of time on stream. Likewise, it is worth mentioning that the catalyst prepared using Na_2CO_3 shows significant activity in this reaction even at temperatures as low as 400℃.