Hydrogen Production via Water Gas Shift Reaction over Noble Metals Nanocatalysts Supported on Nanocrystalline Alumina Stabilized with Magnesium Oxide

Water gas shift reaction is an essential process of hydrogen production and carbon monoxide removal from syngas. In this research, noble metal (Rh, Pt, Pd, Ir, and Ru) nanocatalysts supported on alumina stabilized with magnesium oxide were prepared and employed in high temperature water gas shift reaction for production of hydrogen. The prepared samples were characterized by X-Ray Diffraction (XRD), N2 adsorption (BET), Temperature Programmed Reduction (TPR), H2S chemisorption and Transmission Electron Microscopy (TEM) techniques. The obtained results revealed that the prepared samples showed the BET surface area in the range of 85-179 m2/g. The TEM analysis results showed that the catalysts have a nanocrystalline structure with average crystal size of less than 5 nm, which is in agreement with H2S chemisorption results for measuring the active metal crystallite size. The obtained results indicated that among the prepared catalysts, Ru and Rh showed higher CO conversion due to undesirable methanation reaction. In addition, it was found that amount of methane formation was negligible over Pt catalyst, which implied that all converted carbon monoxide over this catalyst is related to the water gas shift reaction. This catalyst also exhibited stable catalytic performance without any decrease in CO conversion during 10 h time on stream.