Characterizations of bimetallic NiV-supported SiO2 catalysts prepared for effectively hydrogen evolutions from ethanol steam reforming

• Hydrogen selectivity was improved on the Ni8V2/SiO2 catalyst.
• During ESR, the amount of evolved CO gas was relatively low on the NiV/SiO2.
• CH4 and CO molecules were adsorbed predominantly on the surface of metallic Ni and NiV composite, respectively.
• Water molecules were absorbed easily on the surface of the V-sites.

Bimetallic NiV supported on SiO2 catalysts were tested in the steam reforming of ethanol. The catalysts were prepared using a wet impregnation method, and all the catalysts had a Ni oxide or NiV oxide loading of 30 wt.% vs. the SiO2 weight. The catalysts were characterized by energy dispersive X-ray spectroscopy (XPS), nitrogen adsorption/desorption isotherm, X-ray diffraction (XRD), temperature programmed desorption with CO and H2O, and temperature programmed reduction with H2. XRD and XPS revealed the crystallite sizes and oxidation states of the NiO or metallic Ni in NiV/SiO2 catalysts, respectively, which indicated suppressed agglomeration between the Ni particles by the V promoters. The ESR catalytic tests for hydrogen production were performed in a fixed bed reactor containing 0.4 g of catalyst at 650 °C and a 6000 h−1 GHSV after the H2-pretreatment with an inlet H2O:CH3CH2OH ratio of 3:1. These tests showed that hydrogen evolution on the Ni8V2/SiO2 catalyst during ESR was improved by suppressing the deposition of carbon compared to those on the Ni/SiO2 catalyst.

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