Sorption enhanced hydrogen production using one-body CaO–Ca12Al14O33–Ni composite as catalytic absorbent

Catalytic absorbents containing CaO and Ca12Al14O33 and metallic Ni in one body were prepared in combination of precipitation and hydration and tested for sorption enhanced hydrogen production (SEHP). Adding aluminum precursor in the precipitation step induced the formation of Ca12Al14O33 and FIB-TEM analysis revealed that Ca12Al14O33 provides spacious pathway for CO2 diffusion by forming porous structure. In thermogravimetric analysis, Ca12Al14O33 was identified as an excellent support material providing superior cyclic stability for Ca-based sorbent. Catalytic absorbents were prepared with adding various amount of Ni precursor (3, 5, 7, and 10 wt %). The SEHP test with the catalytic absorbents showed that 7wt% of Ni loading resulted in excellent performance in terms of H2 production and CH4 conversion. Ni agglomeration was observed when 10 wt% of Ni is loaded on the catalytic absorbent.

► It was found that Ca12Al14O33 is formed as separate phase in CaO–Ca12Al14O33 and it provides spacious CO2 pathway. ► Precipitation with hydration provides excellent cyclic stability for CO2 absorbent and catalytic absorbent. ► Catalytic absorbent (CaO–Ca12Al14O33–Ni) was prepared and its satisfied performance in SEHP was achieved. ► Around 7 wt% of Ni loading in the catalytic absorbent is optimum for operation of SEHP.