Hydrogen production via water-gas shift reaction over gold supported on Ni-based layered double hydroxides

Co-precipitated NiAl and NiMgAl layered double hydroxides (LDHs) were prepared at M2+/Al3+ molar ratio of 2.5/1 and subsequently promoted with gold targeting to be studied as catalysts and supports of gold particles in the hydrogen production via water-gas shift (WGS) reaction. Powder X-ray diffraction and N-2 physisorption before and after WGS tests were applied to investigate the impacts of Mg and Au on the structure and catalytic behavior of the systems. Partial replacement of Ni by Mg resulted in moderate activity of NiMgAl and Au/NiMgAl catalysts than NiAl analogues due to: (i) smaller Ni amount that could not supply sufficient number catalytically active sites; (ii) higher thermal stability leading to the creation of the active Ni species at higher temperatures, and (iii) partial regeneration of the layered structure with the assistance of small Au particles, Mg, and the reaction medium as well. Favorable role of gold on Au/NiAl WGS activity was elucidated. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

Partial replacement of Ni by Mg resulted in moderate activity of NiMgAl and Au/NiMgAl catalysts than NiAl analogues due to smaller Ni amount that could not supply sufficient number catalystically active sites, higher thermal stability leading to the creation of the active Ni species at higher temperatures, and partial regeneration of the layered structure with the assistance of small Au particles, Mg, and the reaction medium as well.