Mg-promoted Ni-CaO microsphere as bi-functional catalyst for hydrogen production from sorption-enhanced steam reforming of glycerol

Abstract

The sorption-enhanced steam reforming (SESR) process provides a simple way to produce high-purity hydrogen. And a key requirement for SESR is the availability of high cyclic stability of sorbent due to the rapid decline of sorption capacity caused by the sorbent sintering. Herein, we report a facile one-pot hydrothermal synthesis method by using in situ generated carbon microspheres as templates to prepare porous Ni-CaO-MgO bi-functional catalyst. The catalyst possessed MgO-stabilized, Ni and CaO microspheres featuring highly porous structure, which provided sufficient void space for volume variations and reduced the contact between CaO particles which was beneficial to improving the stability. Meanwhile, the uniformly distributed MgO had been found to reduce the particle size of CaO and stabilize the structure of bi-functional catalyst to ensure a stable CO2 uptake. 10Ni-CM7 as the best performing material only required 8.1 wt% MgO, showing 40% loss in sorption-enhanced effect after 10 cycles of repeated SESRG-desorption, where CaO utilization kept 59.1% exceeding the commercial CaO by ~109%.