Abstract: Ni/γ-Al₂O₃ catalyst with high activity in water-gas shift (WGS) reaction was prepared by an impregnation method, and nano-sized Li₂ZrO₃ absorbent with excellent CO₂ capture properties was synthesized by a citrate sol-gel method. Two processes, WGS over 20% Ni/γ-Al₂O₃ catalyst alone and sorption-enhanced WGS (SE-WGS) over 20% Ni/γ-Al₂O₃ catalyst admixing with nano-sized Li₂ZrO₃ absorbent in a fixed-bed microreactor, towards the production of H₂ were compared. The nano-sized Li₂ZrO₃ absorbent shows better CO₂ capture properties than other CO₂ absorbents reported so far in terms of uptake rate and reusability. Based on these excellent properties, the application of the developed Li₂ZrO₃ absorbent in sorption-enhanced reaction process (SERP) for the in-situ removal of CO₂ produced from WGS leads to the equilibrium shift of the reaction to the production of H₂ with high purity. The H₂ purity higher than 98% can be achieved by SE-WGS at 823 K, a total pressure of 0.1 MPa, and a H₂O/CO molar ratio of 4, demonstrating the concept of SERP for H₂ production.

Key words: hydrogen production, carbon dioxide, absorbent, water-gas shift reaction, lithium zirconate