Pd/oxide/cordierite monolithic catalysts(oxide = Al_2O_3, SiO_2 and SiO_2\\Al_2O_3) were prepared by the impregnation method. The results of ICP, XRD, SEM–EDX, XPS and N_2 adsorption–desorption measurements revealed...Pd/oxide/cordierite monolithic catalysts(oxide = Al_2O_3, SiO_2 and SiO_2\\Al_2O_3) were prepared by the impregnation method. The results of ICP, XRD, SEM–EDX, XPS and N_2 adsorption–desorption measurements revealed that the Pd penetration depth increased with increasing the thickness of oxide layer, and the catalysts with Al_2O_3 layers had the larger pore size than those with SiO_2 and SiO_2\\Al_2O_3 layers. Catalytic hydrogenation of 2-ethylanthraquinone(eA Q), a key step of the H_2O_2 production by the anthraquinone process, over the various monolithic catalysts(60 °C, atmosphere pressure) showed that the monolithic catalyst with the moderate thickness of Al_2O_3 layer(about 6 μm) exhibited the highest conversion of e AQ(99.1%) and hydrogenation efficiency(10.0 g·L^(-1)). This could be ascribed to the suitable Pd penetration depth and the larger pore size, which provides a balance between the distribution of Pd and accessibility of active sites by the reactants.展开更多
We studied the hydrogenation of 2‐ethylanthraquinone（eAQ） over Pd/SiO2/COR（COR = cordierite） monometallic and Pd‐M/SiO2/COR（M = Ni, Fe, Mn, and Cu） bimetallic monolithic catalysts, which were prepared by the c...We studied the hydrogenation of 2‐ethylanthraquinone（eAQ） over Pd/SiO2/COR（COR = cordierite） monometallic and Pd‐M/SiO2/COR（M = Ni, Fe, Mn, and Cu） bimetallic monolithic catalysts, which were prepared by the co‐impregnation method. Detailed investigations showed that the particle sizes and structures of the Pd‐M（M = Ni, Fe, Mn, and Cu） bimetallic monolithic catalysts were great‐ly affected by the second metal M and the mass ratio of Pd to the second metal M. By virtue of the small particle size and the strong interaction between Pd and Ni of Pd‐Ni alloy, Pd‐Ni bimetallic monolithic catalysts with the mass ratio of Pd/Ni = 2 achieved the highest H2O2 yield（7.5 g/L） and selectivity（95.3%）. Moreover, density functional theory calculations were performed for eAQ ad‐sorption to gain a better mechanistic understanding of the molecule‐surface interactions between eAQ and the Pd（1 1 1） or PdM（1 1 1）（M = Ni, Fe, Mn, and Cu） surfaces. It was found that the high activity of the bimetallic Pd‐Ni catalyst was a result of strong chemisorption between Pd3Ni1（1 1 1） and the carbonyl group of eAQ.展开更多
基金Supported by the Sinopec Corp.Scientific Research Projects(414076)
文摘Pd/oxide/cordierite monolithic catalysts(oxide = Al_2O_3, SiO_2 and SiO_2\\Al_2O_3) were prepared by the impregnation method. The results of ICP, XRD, SEM–EDX, XPS and N_2 adsorption–desorption measurements revealed that the Pd penetration depth increased with increasing the thickness of oxide layer, and the catalysts with Al_2O_3 layers had the larger pore size than those with SiO_2 and SiO_2\\Al_2O_3 layers. Catalytic hydrogenation of 2-ethylanthraquinone(eA Q), a key step of the H_2O_2 production by the anthraquinone process, over the various monolithic catalysts(60 °C, atmosphere pressure) showed that the monolithic catalyst with the moderate thickness of Al_2O_3 layer(about 6 μm) exhibited the highest conversion of e AQ(99.1%) and hydrogenation efficiency(10.0 g·L^(-1)). This could be ascribed to the suitable Pd penetration depth and the larger pore size, which provides a balance between the distribution of Pd and accessibility of active sites by the reactants.
基金supported by the National Natural Science Foundation of China (21476009, 21406007, U1462104)~~
文摘We studied the hydrogenation of 2‐ethylanthraquinone（eAQ） over Pd/SiO2/COR（COR = cordierite） monometallic and Pd‐M/SiO2/COR（M = Ni, Fe, Mn, and Cu） bimetallic monolithic catalysts, which were prepared by the co‐impregnation method. Detailed investigations showed that the particle sizes and structures of the Pd‐M（M = Ni, Fe, Mn, and Cu） bimetallic monolithic catalysts were great‐ly affected by the second metal M and the mass ratio of Pd to the second metal M. By virtue of the small particle size and the strong interaction between Pd and Ni of Pd‐Ni alloy, Pd‐Ni bimetallic monolithic catalysts with the mass ratio of Pd/Ni = 2 achieved the highest H2O2 yield（7.5 g/L） and selectivity（95.3%）. Moreover, density functional theory calculations were performed for eAQ ad‐sorption to gain a better mechanistic understanding of the molecule‐surface interactions between eAQ and the Pd（1 1 1） or PdM（1 1 1）（M = Ni, Fe, Mn, and Cu） surfaces. It was found that the high activity of the bimetallic Pd‐Ni catalyst was a result of strong chemisorption between Pd3Ni1（1 1 1） and the carbonyl group of eAQ.
