화학공학소재연구정보센터
Applied Catalysis B: Environmental, Vol.238, 576-585, 2018
Alkaline zirconates as effective materials for hydrogen production through consecutive carbon dioxide capture and conversion in methane dry reforming
In this work, H-2 production was evaluated using different carbonation conditions and two alkaline zirconates. For this purpose, Li2ZrO3 and Na2ZrO3 were synthesized, characterized and tested on a consecutive process composed of initial CO2 capture, followed by methane dry reforming (MDR). Thermogravimetric results showed that under the four gas mixtures tested (diluted and saturated CO2, CO and CO-O-2), both ceramics are able to chemisorb CO2, with Na2ZrO3 having the highest capture with saturated CO2. In catalytic tests, ceramics carbonated with saturated CO2 or CO-O-2 gas flows were able to act as sorbents and catalysts, producing H-2 at T > 750 degrees C through the partial oxidation of methane. This reaction was produced because CO2 desorption did not occur, thus avoiding the MDR process. On the other hand, carbonated ceramics under a CO-O-2 gas mixture presented an outstanding catalytic performance. Between 450 and 750 degrees C, H-2 was formed through the MDR process promoted by CO2 desorption from both ceramics. This result is in line with CO2 desorption results, where a weaker CO2-solid interaction was observed in comparison with saturated CO2. Afterward, both ceramics presented a similar catalytic behavior, good regeneration and cyclability after the double process proposed (CO2 capture-MDR reaction). Lithium zirconate also presented high thermal stability during cycle tests; meanwhile, sodium zirconate showed an important H-2 production increase as a function of cycles. Finally, both materials are feasible options for producing a clean energy source in a moderate temperature range through the catalytic conversion of two greenhouse gases (CO2 and CH4).