有机蒙脱土负载镍催化剂上乙醇重整制氢

采用浸渍法制备了有机改性蒙脱土(OMt)负载的Ni/有机蒙脱土(Ni/OMt)催化剂,用于乙醇重整制氢;通过XRD、FT-IR、H₂-TPR、SEM、XPS和氮吸附等手段对催化剂进行了表征分析。结果表明,与未改性的蒙脱土负载的Ni催化剂(Ni/MMT)相比,有机改性可显著提高其比表面积、孔容和金属Ni的分散度,降低碳沉积量,改善Ni/MMT催化剂的稳定性。Ni/OMt催化剂表现出较高的乙醇重整制氢催化性能,在773K下反应30 h,乙醇转化率保持在100%,氢气选择性为70%;而Ni/MMT催化剂在反应10 h即开始失活,碳沉积严重,同时产生副产物乙烯和乙醛。使用十六烷基三甲基溴化铵(CTAB)改性可促进Ni高分散在MMT层板上,抑制积炭对活性金属Ni包裹,提高其乙醇重整氢气选择性、降低乙烯和乙醛的选择性。

Catalytic performance of nickel immobilized on organically modified montmorillonite in the steam reforming of ethanol for hydrogen production

Nickel immobilized on organically modified montmorillonite (Ni/OMt) was prepared by impregnation method and used as the catalyst for hydrogen production from ethanol steam-reforming;the Ni/OMt catalyst was characterized by XRD, FT-IR, H₂-TPR, SEM, XPS and N₂ adsorption-desorption. The results indicate that in comparison with the catalyst of nickel supported on unmodified montmorillonite (Ni/MMT), the Ni/OMt catalyst exhibits higher surface area and pore volume as well as higher nickel dispersion with smaller metallic particle size. For the ethanol steam-reforming over Ni/OMt, the conversion of ethanol keeps at 100%, with a selectivity of 70% to hydrogen during the 30h reaction test at 773K;however, over the unmodified Ni/MMT catalyst, severe carbon deposition is observed after reaction for only 10h, accompanying with catalyst deactivation and the formation of byproducts such as acetaldehyde and ethylene. The modification of MMT with cetyltrimethylammonium bromide (CTAB) can significantly improve the stability of the Ni/OMt catalyst in ethanol steam-reforming and reduce the carbon deposition rate by immobilizing highly dispersed nanoparticle Ni on the interlayers of OMt;the selectivity to ethylene and acetaldehyde is also greatly depressed.