Ni_2P/Ti-MCM-41的催化加氢脱硫性能
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摘要
以MCM-41和Ti-MCM-41介孔分子筛为载体,低温还原法(400℃)制备了磷化镍催化剂。采用XRD、BET、FT-IR、Py-FT-IR、XPS、CO吸附等手段对催化剂进行了表征。采用固定床反应器,以二苯并噻吩为模型化合物,评价了磷化镍催化剂的加氢脱硫催化性能。结果表明,金属Ti的引入可以增强载体和催化剂的B酸和L酸酸性;金属Ti因其电子助剂的作用,能够促进更细小尺寸的Ni_2P活性相的形成。在反应温度340℃、反应压力3.0 MPa、质量空速(MHSV)3.5h~(-1)、V(H_2)/V(Oil)=650的条件下,Ni_2P/Ti-MCM-41催化二苯并噻吩加氢脱硫反应的转化率高达99.38%,与相同条件下制备的Ni_2P/MCM-41相比,提高了约17百分点。Ni_2P/Ti-MCM-41催化剂具有更优的原料处理能力和更佳的催化活性的原因可归结为金属Ti的电子效应、活性相的尺寸和分散度以及催化剂适宜的酸性。
Ni_2P/MCM-41 and Ni_2P/Ti-MCM-41 catalysts were successfully prepared by temperature programmed reduction method at a low reduction temperature(400℃).The obtained catalysts were characterized by XRD,BET,FT-IR,Py-FT-IR,XPS,TEM and CO uptake.The catalytic hydrodesulfurization(HDS)performance of Ni_2P/Ti-MCM-41 was investigated on a fixed bed and with dibenzothiophene(DBT)as model compound.The results indicated that the introduction of Ti into MCM-41 can modify the acidic nature of supports and catalysts and enhance the Lewis acidity as well as the Brnsted acid intensity of supports,being beneficial to the formation of Ni_2 P active phase because of the electronic properties of Ti.At the conditions of 340℃,3.0MPa,mass hourly space velocity(MHSV)of 3.5h~(-1) and H_2/oil volume ratio of 650,catalyzed by Ni_2P/Ti-MCM-41 the conversion of DBT HDS reached 99.38%,17% higher than that catalyzed by Ni_2P/MCM-41 catalyst.The electronic effect of Ti,size of active phase and its dispersion,and the moderate surface acidity of catalyst may be responsible to the enhancement of HDS catalytic activity of the Ti-doped samples.
Ni_2P/MCM-41 and Ni_2P/Ti-MCM-41 catalysts were successfully prepared by temperature programmed reduction method at a low reduction temperature(400℃).The obtained catalysts were characterized by XRD,BET,FT-IR,Py-FT-IR,XPS,TEM and CO uptake.The catalytic hydrodesulfurization(HDS)performance of Ni_2P/Ti-MCM-41 was investigated on a fixed bed and with dibenzothiophene(DBT)as model compound.The results indicated that the introduction of Ti into MCM-41 can modify the acidic nature of supports and catalysts and enhance the Lewis acidity as well as the Brnsted acid intensity of supports,being beneficial to the formation of Ni_2 P active phase because of the electronic properties of Ti.At the conditions of 340℃,3.0MPa,mass hourly space velocity(MHSV)of 3.5h~(-1) and H_2/oil volume ratio of 650,catalyzed by Ni_2P/Ti-MCM-41 the conversion of DBT HDS reached 99.38%,17% higher than that catalyzed by Ni_2P/MCM-41 catalyst.The electronic effect of Ti,size of active phase and its dispersion,and the moderate surface acidity of catalyst may be responsible to the enhancement of HDS catalytic activity of the Ti-doped samples.
引文
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[23]WANG H M,PRINS R.Hydrodesulfurization of dibenzothiophene and its hydrogenated intermediates over sulfided Mo/γ-Al2O3[J].Journal of Catalysis,2008,258(1):153-164.
[24]KANDA Y,KOBAYASHI T,UEMICHI Y,et al.Effect of aluminum modification on catalytic performance of Pt supported on MCM-41 for thiophene hydrodesulfurization[J].Applied Catalysis A:General,2006,308:111-118.
[25]LIU P,RODRIGUEZ J A.Catalysts for hydrogen evolution from the[NiFe]hydrogenase to the Ni2P(001)surface:The importance of ensemble effect[J].Journal the American Chemical Society,2005,127(42):14871-14878.
[26]NIQUILLE-ROTHLISBERGER A,PRINS R.Hydrodesulfurization of 4,6-dimethyldibenzothiophene over Pt,Pd,and Pt-Pd catalysts supported on amorphous silicaalumina[J].Catalysis Today,2007,123(1-4):198-207.
[27]SILVA-RODRIGO R,CALDERON-SALAS C,MELOBANDA J A,et al.Synthesis,characterization and comparison of catalytic properties of NiMo-and NiW/Ti-MCM-41catalysts for HDS of thiophene and HVGO[J].Catalysis Today,2004,98(1-2):123-129.
[2]宋华,代敏,宋华林.Ni2P加氢脱硫催化剂化学进展[J].化学进展,2012,24(5):43-47.(SONG Hua,DAI Min,SONG Hualin.Ni2P catalyst for hydrodesulfurization[J].Progress in Chemistry,2012,24(5):43-47.)
[3]SONG H,DAI M,SONG H L,et al.Synthesis of a Ni2P catalyst supported on anatase-TiO2 whiskers with high hydrodesulfurization activity,based on triphenylphosphine[J].Catalysis Communications,2014,43:151-154.
[4]SONG H,DAI M,GUO Y T,et al.Preparation of composite TiO2-Al2O3 supported nickel phosphide hydrotreating catalysts and catalytic activity for hydrodesulfurization of dibenzothiophene[J].Fuel Processing Technology,2012,96:228-236.
[5]SONG H,DAI M,SONG H L,et al.A novel synthesis of Ni2P/MCM-41 catalysts by reducing a precursor of ammonium hypophosphite and nickel chloride at low temperature[J].Applied Catalysis A:General,2013,462-463:247-255.
[6]MELENDEZ-ORTIZ H I,GARCIA-CERDA L A,OLIVARES-MALDONADO Y,et al.Preparation of spherical MCM-41molecular sieve at room temperature:Influence of the synthesis conditions in the structural properties[J].Ceramics International,2012,38(8):6353-6358.
[7]KONG Y,ZHU H Y,YANG G,et al.Investigation of the structure of MCM-41samples with a high copper content[J].Advanced Functional Materials,2004,14(8):816-820.
[8]SHI Y,WANG S P,MA X B.Microwave preparation of Ti-containing mesoporous materials.Application as catalysts for transesterification[J].Chemical Engineering Journal,2011,166(2):744-750.
[9]KOSSLICK H,LISCHKE G,LANDMESSER H,et al.Acidity and catalytic behavior of substituted MCM-48[J].Journal of Catalysis,1998,176(1):102-114.
[10]WANG X Q,CLARK P,OYAMA S T.Synthesis,characterization,and hydrotreating activity of several iron group transition metal phosphides[J].Journal of Catalysis,2002,208(2):321-331.
[11]OYAMA S T,WANG X Q,LEE Y K,et al.Active phase of Ni2P/SiO2 in hydroprocessing reactions[J].Journal of Catalysis,2004,221(2):263-273.
[12]LI X,LU M H,WANG A J,et al.Promoting effect of TiO2on the hydrodenitrogenation performance of nickel phosphide[J].Journal of Physical Chemistry C,2008,112(42):16584-16592.
[13]EIMER G A,CASUSCELLI S G,CHANQUIA C M,et al.The influence of Ti-loading on the acid behavior and on the catalytic efficiency of mesoporous Ti-MCM-41 molecular sieves[J].Catalysis Today,2008,133-135:639-646.
[14]AREAN C O,DELGADO M R,MONTOUILLOUT V,et al.NMR and FTIR spectroscopic studies on the acidity of gallia-silica prepared by a sol-gel route[J].Microporous and Mesoporous Materials,2004,67:259-264.
[15]DUAN X Q,TENG Y,WANG A J,et al.Role of sulfur in hydrotreating catalysis over nickel phosphide[J].Journal of Catalysis,2009,261(2):232-240.
[16]SHU Y Y,LEE Y K,OYAMA S T.Structure-sensitivity of hydrodesulfurization of 4,6-dimethyldibenzothiophene over silica-supported nickel phosphide catalysts[J].Journal of Catalysis,2005,236(1):112-121.
[17]FUKS D,VINGURT D,LANDAU M V,et al.Density functional theory study of sulfur adsorption at the(001)surface of metal-rich nickel phosphides:Effect of the Ni/P ratio[J].Journal of Physical Chemistry C,2010,114(31):13313-13321.
[18]LIU P,RODRIGUEZ J A,ASAKURS T,et al.Desulfurization reactions on Ni2P(001)andα-Mo2C(001)surfaces:Complex role of P and C sites[J].Journal of Physical Chemistry B,2005,109(10):4575-4583.
[19]LAYMAN K A,BUSSELL M E.Infrared spectroscopic investigation of CO adsorption on silicasupported nickel phosphide catalysts[J].Journal of Physical Chemistry B,2004,108(30):10930-10941.
[20]OYAMA S T.Novel catalysts for advanced hydroprocessing:Transition metal phosphides[J].Journal of Catalysis,2003,216(1-2):343-352.
[21]OYAMA S T,WANG X,LEE Y K,et al.Effect of phosphorus content in nickel phosphide catalysts studied by XAFS and other techniques[J].Journal of Catalysis,2002,210(1):207-217.
[22]HOUALLA M,BRODERICK D H,SAPRE A V,et al.Hydrodesulfurization of methyl-substituted dibenzothiophenes catalyzed by sulfided Co-Mo/γ-Al2O3[J].Journal of Catalysis,1980,61(2):523-527.
[23]WANG H M,PRINS R.Hydrodesulfurization of dibenzothiophene and its hydrogenated intermediates over sulfided Mo/γ-Al2O3[J].Journal of Catalysis,2008,258(1):153-164.
[24]KANDA Y,KOBAYASHI T,UEMICHI Y,et al.Effect of aluminum modification on catalytic performance of Pt supported on MCM-41 for thiophene hydrodesulfurization[J].Applied Catalysis A:General,2006,308:111-118.
[25]LIU P,RODRIGUEZ J A.Catalysts for hydrogen evolution from the[NiFe]hydrogenase to the Ni2P(001)surface:The importance of ensemble effect[J].Journal the American Chemical Society,2005,127(42):14871-14878.
[26]NIQUILLE-ROTHLISBERGER A,PRINS R.Hydrodesulfurization of 4,6-dimethyldibenzothiophene over Pt,Pd,and Pt-Pd catalysts supported on amorphous silicaalumina[J].Catalysis Today,2007,123(1-4):198-207.
[27]SILVA-RODRIGO R,CALDERON-SALAS C,MELOBANDA J A,et al.Synthesis,characterization and comparison of catalytic properties of NiMo-and NiW/Ti-MCM-41catalysts for HDS of thiophene and HVGO[J].Catalysis Today,2004,98(1-2):123-129.