Steam treatment on Ni/γ-Al2O3 for enhanced carbon resistance in combined steam and carbon dioxide reforming of methane

Coke deposition on reforming reaction catalysts, typically Ni particles deposited on alumina supports, has been a major obstacle barring their practical industrial application. In this work, a Ni/γ-Al2O3 catalyst was stabilized by a pretreatment with steam at high temperature of 850 °C. The steam-treated Ni/γ-Al2O3 catalyst showed thermodynamically possible highest conversion (98.3% for methane and 82.4% for carbon dioxide) and H2/CO ratio of 2.01 for combined steam and carbon dioxide reforming of methane, and operated stably for 200 h. The amount of deposited carbon coke was 3.6% for steam-treated catalysts whereas conventional catalysts had 15.4% of coke after 200 h of the reaction. The steam pretreatment removed unstable aluminum that can otherwise leach out, which causes severe carbon deposition at the early stage of the reaction. This novel steam pretreatment enhanced the carbon resistance of the catalysts significantly, resulting in improved activity and long-term stability.

Graphical abstractThe steam pretreatment on Ni/γ-Al2O3 catalyst enhanced the carbon resistance of the catalyst, resulting in improved activity and long-term stability for combined steam and carbon dioxide reforming of methane.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The combined steam and carbon dioxide reforming of methane was studied. ► Carbon coke was diminished by steam treatment on conventional Ni/Al2O3 catalyst. ► Steam pretreatment reduced aluminum leaching which caused severe coke formation. ► Steam pretreatment improved activity and long-term stability for the reaction. ► H2/CO ratio was closer to two, which is desirable for Fischer–Tropsch reaction.