page_title: Water-gas shift reaction
section_title: Temperature dependence
hierarchical_section_title: Water-gas shift reaction / Reaction conditions / Temperature dependence
caption_attribution_description: English: Keq WGS Temperature Dependence
context_page_description: The water-gas shift reaction describes the reaction of carbon monoxide and water vapor to form carbon dioxide and hydrogen:
  CO + H₂O ⇌ CO₂ + H₂
  The water gas shift reaction was discovered by Italian physicist Felice Fontana in 1780. It was not until much later that the industrial value of this reaction was realized. Before the early 20th century, hydrogen was obtained by reacting steam under high pressure with iron to produce iron, iron oxide and hydrogen. With the development of industrial processes that required hydrogen, such as the Haber–Bosch ammonia synthesis, a less expensive and more efficient method of hydrogen production was needed. As a resolution to this problem, the WGSR was combined with the gasification of coal to produce a pure hydrogen product. As the idea of hydrogen economy gains popularity, the focus on hydrogen as a replacement fuel source for hydrocarbons is increasing.
context_section_description: The water gas shift reaction is a moderately exothermic reversible reaction. Therefore, with increasing temperature the reaction rate increases but the conversion of reactants to products becomes less favorable. Due to its exothermic nature, high carbon monoxide conversion is thermodynamically favored at low temperatures. Despite the thermodynamic favorability at low temperatures, the reaction is kinetically favored at high temperatures. 
  The water-gas shift reaction is sensitive to temperature, with a tendency to shift towards reactants as temperature increases due to Le Chatelier's principle. Over the temperature range 600–2000 K, the equilibrium constant for the WGSR has the following relationship:
caption: A plot of the temperature dependence of Keq, the value of which approaches 1 at 1100 K.[2]
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