Production of fuel-cell grade hydrogen by sorption enhanced water gas shift reaction using Pd/Ni–Co catalysts

It has been demonstrated both thermodynamically and experimentally that fuel-cell grade hydrogen can be produced by a one-step sorption enhanced water gas shift (SEWGS) process at about 500 °C, where the water gas shift (WGS) catalyst and the CO2 sorbent are highly integrated. A synthetic CaO-based mixed oxide sorbent was also assessed, which showed a good CO2 capture capacity and stability in the cyclic operation of the SEWGS reaction. Catalysts play a significant role in CO conversion via WGS, methanation and methane steam reforming reactions. A Pd promoted Ni–Co catalyst (1%Pd/20%Ni–20%Co) derived from hydrotalcite-like material (HT) showed a high activity for WGS and methane steam reforming. The methanation activity was further reduced on 30%Ni–10%Co. There exists an optimum temperature (500 °C) for hydrogen production by the SEWGS process, where it is kinetically limited by the WGS reaction at lower temperatures (425–475 °C) and it is thermodynamically unfavorable at higher temperatures (475–550 °C). The challenges for hydrogen production by SEWGS at high CO pressures were also demonstrated, where CO pressure has shown a negative influence on WGS activity. An induction period was observed, which can be reduced by improving catalyst activity and by adding hydrogen to the reactant mixture.

Bibliographic Details

Main Authors:	Noor, Tayyaba, Gil Matellanes, María Victoria, Chen, De
Format:	artículo biblioteca
Language:	English
Published:	Elsevier 2014-05-05
Subjects:	CO conversion, Fuel cells, Hydrogen, Pd/Ni–Co-hydrotalcite catalyst, Sorption enhanced water gas shift,
Online Access:	http://hdl.handle.net/10261/103629
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