Medium‐Temperature Shift Catalysts for Hydrogen Purification in a Single‐Stage Reactor

Abstract

Interest regarding the WGS process has grown significantly, because of the recent progression in fuel cells as a clean technology for power generation. Due to the large volume and cost of WGS conventional two-stage reactors, and also problems related to pyrophoricity and lengthy reduction of customary catalysts, the current challenge is to develop more active and stable catalysts that convert CO in a single-stage medium temperature shift (MTS, 280-360°C) reactor, which is applicable in small-scale fuel cells. Advanced and newly developed catalytic systems for hydrogen purification via MTS reactions are reviewed and discussed in this study. Pt-based catalysts on reducible oxide supports, e.g., CeO 2 and TiO 2 , have mainly been used for this reaction. It is known that ceria is the most applicable active and stable support and highly promising for MTS reactions, considering its high oxygen storage capacity and mobility of surface oxygen/hydroxyl groups. New studies investigate modified ceria, e.g., CeZr, to improve its catalytic properties. Figure 8. The effect of Cu-loading on the WGS reaction over Cu-CeO 2 catalyst at 150-360°C [91].

Nickel‐based Catalysts for High‐temperature Water Gas Shift Reaction‐Methane Suppression

“…Thus, it can be observed from these contexts that water gas shift (WGS) reaction plays vital industrial role in adjusting and increasing H 2 concentration [Eq. ] …”

Comparison of Preparation Methods of Iron‐Based Catalysts for High‐Temperature Water‐Gas Shift Reaction

“…It is suggested that Cu in the magnetite structure modifies the electronic properties of the standard Fe 3 O 4 /Cr 2 O 3 catalyst [16]. Moreover, in recent years, this process has also been developed using Ni and Cu supported on the nanocrystalline CeO 2 , ZrO 2 , and combination of these metal oxides [19][20][21].…”

Effect of surfactants and digestion time on nano crystalline cerium oxide characteristics synthesized by differential precipitation

“…However, performance of ceria in above uses is strongly influenced by the physical properties of ceria particles [7]. Easier reducibility of ceria as well as high oxygen storage capacity and mobility of surface oxygen will make ceria as a good choice for catalyst support [8].…”

“…Universally, cerium (III) nitrate and different precipitation agents, including ammonia [7][8][9][10][11], sodium hydroxide [12] and urea [13] were used for synthesizing of ceria. Use of high amount of precipitation agent and high temperature for precipitation of cerium cations are the main defects for these agents.…”