High Purity Hydrogen Production by Sorption‐Enhanced Ethanol Steam Reforming over Lithium Cuprate Based Hybrid Material.

Abstract

High‐purity H 2 production via sorption‐enhanced ethanol steam reforming (SR) over a novel bifunctional material consisting of nickel (Ni), hydrotalcite (HTlc), and lithium cuprate (Li 2 CuO 2 ) is investigated. Three hybrid materials (HM): Ni/HTlc, Ni/Li 2 CuO 2 , and Ni/HTlc/Li 2 CuO 2 with 10 wt% Ni loading are synthesized by wet impregnation Ni/HTlc/Li 2 CuO 2 contained 45 wt% each of HTlc and Li 2 CuO 2 . Their catalytic activities are assessed for H 2 production in a fixed‐bed down‐flow reactor. Ni/HTlc/Li 2 CuO 2 is found to be the best choice. The effects of temperature, feed flow rate, and steam‐to‐carbon molar ratio ( S / C ) variation on the purity of H 2 and ethanol conversion are studied. All reactions are carried out at atmospheric pressure. The optimum process parameters are: T = 500 °C, feed flow rate = 0.5 mL min −1 , and S / C = 9 mol mol −1 . At optimum reaction conditions, ethanol conversion is 94%, H 2 yield = 89%, H 2 purity ≈94 mol%, breakthrough time = 20 min, and adsorption capacity = 4.3 mmol CO 2 per gram of material. HM is able to produce >90% pure H 2 till the 14th adsorption–desorption cycle. The material is regenerated by simply passing N 2 gas and steam at 500 °C for 30 min. A probable reaction mechanism indicates the dehydrogenation of ethanol to acetaldehyde followed by rapid SR of acetaldehyde. This study is the first to explore the application of Li 2 CuO 2 for any SR process.