A mini review on the chemistry and catalysis of the water gas shift reaction

TL;DR

This review discusses the chemistry and catalysis of the water gas shift reaction, emphasizing the roles of active metals and supports, and highlighting how different metals influence catalytic activity and support effects.

Contribution

It provides a comprehensive overview of the catalytic mechanisms and the influence of various metals and supports on the water gas shift reaction, including new insights into support effects and metal activation.

Findings

Catalytic activity correlates with CO adsorption heat in a volcano trend.

Support effects significantly influence catalytic performance, as seen with Pt/Al2O3 versus Pt/SiO2.

Different metals exhibit varying activation energies for CO activation.

Abstract

Water gas shift (WGS) reaction is a chemical reaction in which carbon monoxide reacts with water vapor to form carbon dioxide and hydrogen. It is an important reaction industrially used in conjunction with steam reforming of hydrocarbons for the production of high purity hydrogen. Grenoble et al examined the roles of both active metals and metal oxide support on the kinetics of the WGS reaction. They found out that the turn over numbers of various Al2O3 supported transition metals decreased in the trend of Cu, Re, Co, Ru, Ni, Pt, Os, Au, Fe, Pd, Rh, and Ir, which corresponds nicely to the observed volcano shaped correlation between catalytic activities and respective CO adsorption heat. This is a strong indication that CO gets activated on the metal surface during the reaction and different metals have different activation energies. The authors also observed that the turn over number of Pt/Al2O3 was one order of magnitude higher than that of Pt/SiO2, indicating a strong support effect, which the authors ascribed to the activation of H2O.