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摘要: 以天然层状黏土蒙脱石(MMT)为前体,通过液相沉积-沉淀将镍物种引入水溶液中剥离为MMT纳米片表面的简易方法制得Ni/MMT纳米片。该Ni/MMT纳米片由于是二维(2D)结构,利于芳烃及其加氢产物的传质扩散,相比Ni/SBA-15和Ni/γ-Al2O3催化剂,具有更为高效的芳烃加氢性能,且在镍负载量高达18.5%时,其四氢萘加氢的转化频率(TOF)达到最高值。Abstract: Using montmorillonite (MMT), a natural layered clay, as the layered precursor, nanosheets of Ni/MMT are obtained via a facile method, in which the nickel components are introduced on to the surface of the exfoliated MMT nanosheets dispersed in water via deposition-precipitation with nickel nitrate and urea. Due to their unique properties originated from the two-dimensional (2D) structure, which favors mass transfer and diffusion of the aromatics and their hydrogenation products over the catalyst during reaction, the obtained nanosheets of Ni/Clay show higher efficient for hydrogenation of aromatics than Ni/SBA-15 and Ni/γ-Al2O3 catalysts. And the highest TOF for hydrogenation of tetralin over the nanosheets of Ni/Clay is obtained as nickel loading being high to 18.5%.
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Key words:
- nanaosheets /
- Ni/Clay /
- montmorillonite /
- hydrogenation /
- aromatics
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Table 1 Textural properties of the catalysts determined by N2 adsorption
Catalyst Ni Loading
w/%BET surface
area A/(m2·g-1)Pore volume
v/(cm3·g-1)Pore diameter
d/nmMMT - 9 0.05 20.9 Ni/MMT 9.9 9 0.04 15.5 Ni/MMT-ultrasonic 10.1 44 0.10 8.9 Ni/MMT-nanosheets 12.3 144 0.23 6.5 Ni/SBA-15[20] 10.2 334 0.69 7.5 Table 2 Activity of Ni/MMT-nanosheet for hydrogenation of naphthalene a
Catalyst Ni loading
w/%Conversion
x/%Selectivity s/% TOFb/
h-1Ni0 size
d/nmtetralin decalin Ni/MMT 9.9 13.1 99.3 0.7 5.1 19.8 Ni/MMT-ultrasonic 10.1 19.8 99.1 0.9 7.6 - Ni/MMT-nanosheet 12.3 100.0 85.4 14.6 37.8 7.2 Ni/SBA-15 [20] 10.2 68.2 93.6 6.4 28.0 3.7 Ni/γ-Al2O3 [20], c 9.8 42.5 99.2 0.8 8.4 2.2 a: reaction conditions: the solution of naphthalene in n-dodecane (10.0%) 10 g, catalyst 0.12 g, 300 ℃, p(H2) = 5.0 MPa, 2.0 h; b: turnover frequency (TOF) was defined as number of moles of consumed H2 per mole of Ni per hour; c: solution of naphthalene in n-dodecane is 5.0% for reaction Table 3 Activities of Ni/MMT-nanosheet with different nickel loading for hydrogenation of tetralina
Catalyst Ni loading
w/%Conversion
x/%TOFb/
h-1Ni/MMT 9.9 2.1 8.5 Ni/MMT-ultrasonic 10.1 3.7 14.6 5.7 11.7 82.0 Ni/MMT-nanosheets 12.3 35.0 113.7 18.5 78.6 169.8 27.7 55.2 79.6 a: reaction conditions: tetralin 3.0 g, catalyst 0.05 g, 300 ℃, p(H2) = 5.0 MPa, 2.0 h; b: turnover frequency (TOF) was defined as number of moles of consumed H2 per mole of Ni per hour Table 4 Physical properties of Ni/MMT-nanosheet catalysts with different nickel loadings
Catalyst Ni w/% BET surface area A/(m2·g-1) Pore volume v/(cm3·g-1) Pore diameter d/nm Ni/MMT-nanosheet 5.7 128 0.22 6.6 12.3 144 0.23 6.5 18.5 168 0.38 9.1 27.7 125 0.37 11.9 -
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