Hydrogen Production From Steam Reforming Biomass Oil Over Metal Pt Modified Ni/MgO Catalyst

In order to improve the activity of mesoporous Ni/MgO catalyst in hydrogen production by steam reforming biomass oil,metallic Pt was used to modify the catalyst Ni/MgO.A series of Ni/MgO catalysts with various Ni loadings were prepared and applied in hydrogen production by steam reforming of hydroxyacetone.After screening,a suitable Ni/MgO catalyst was obtained and then a series of Pt-Ni/MgO catalysts with various Pt loadings were prepared based on a suitable Ni/MgO catalyst.The catalysts were characterized by N₂ adsorption/desorption,XRD,H₂-TPR,XPS and TEM.In addition,to discuss the modification effect of Pt on Ni/MgO catalyst,the catalytic activities of Ni/MgO and Pt-Ni/MgO in steam reforming hydroxyacetone and commercial biomass oil were investigated in a fixed bed reactor.The results of N₂ adsorption/desorption and XRD show that the MgO support,NiO/MgO and Pt-NiO/MgO precursors were mesoporous structures.H₂-TPR result showed that the Ni reducibility increased from 20.65%on Ni/MgO to 25.25%on Pt-Ni/MgO after the addition of an appropriate amount of Pt.TEM and XPS results showed that after adding an appropriate amount of metallic Pt,the Ni metallic particles decreased from 6.91 nm on Ni/MgO to 4.45 nm on Pt-Ni/MgO.Thus,the modification of Pt increased the active position and dispersion of the active Ni.The results of steam reforming of hydroxyacetone on Ni/MgO and Pt-Ni/MgO catalysts showed that the modification of metallic Pt could significantly enhanced the activity of Ni/MgO catalyst.At 475 ^oC and water to carbon ratio S/C=10 mol/mol,the yield and selectivity of hydrogen were increased from 30.77%and 68.05%on Ni/MgO to 53.38%and 73.78%on 2Pt-250Ni/MgO,respectively.At 475 ^oC and water to carbon ratio S/C=10 mol/mol,the yield of hydrogen increased from 24.35%on Ni/MgO to 45.58%on 2Pt-250Ni/MgO in hydrogen production by steam reforming bio-oil A（from the pyrolysis of corn stalks）.The yield of hydrogen increased from 28.41%on Ni/MgO to 50.62%on 2Pt-250Ni/MgO in hydrogen production by steam reforming bio-oil B（from emulsification and catalytic cracking of agricultural and forestry product residues）.It can be seen that the modification of Pt significantly improved the hydrogen production activity of Ni/MgO catalytic steam reforming from commercial bio-oil.In summary,the catalytic activity of mesoporous Ni/MgO catalyst was significantly improved by addition of metallic Pt in hydrogen production by steam reforming hydroxyacetone or commercial bio-oil.It is also showed that Ni based and Pt-Ni based catalysts have potential applications in hydrogen production by steam reforming of biomass oil.