Efficient Hydrogenolysis of Guaiacol over Highly Dispersed Ni/MCM-41 Catalyst Combined with HZSM-5

A series of MCM-41 supported Ni catalysts with high metal dispersion was successfully synthesized by simple co-impregnation using proper ethylene glycol (EG). The acquired Ni-based catalysts performed the outstanding hydrogenolysis activity of guaiacol. The effects of the synthesis parameters including drying temperature, calcination temperature, and metal loading on the physical properties of NiO nanoparticles were investigated through the use of X-ray diffraction (XRD). The drying temperature was found to significantly influence the particle sizes of NiO supported on MCM-41, but the calcination temperature and metal loading had less influence. Interestingly, the small particle size (≤3.3 nm) and the high dispersion of NiO particles were also obtained for co-impregnation on the mixed support (MCM-41:HZSM-5 = 1:1), similar to that on the single MCM-41 support, leading to excellent hydrogenation activity at low temperature. The guaiacol conversion could reach 97.9% at 150 °C, and the catalytic activity was comparative with that of noble metal catalysts. The hydrodeoxygenation (HDO) performance was also promoted by the introduction of acidic HZSM-5 zeolite and an 84.1% yield of cyclohexane at 240 °C was achieved. These findings demonstrate potential applications for the future in promoting and improving industrial catalyst performance

Urchin-like CoCu Bimetallic Nanocomposites for Catalytic Hydrogenolysis of Glycerol to Propanediols

Bimetallic CoCu nanocomposites were synthesized in polyol by using Ru as heterogeneous nucleation agent and stearic acid as surfactant, and their catalytic properties were investigated by hydrogenolysis of glycerol to propanediols. It was found that the surfactant could induce Co nanocrystals to form nanowires as structure-directing agent, while it's ineffective for Cu because only spherical Cu particles were produced under the same condition. When Co~(2+) and Cu~(2+) coexist in polyol, Cu~(2+) is firstly reduced and forms the spherical particles, and then the Cu particles afford surface for the subsequential reduction of Co~(2+) and growth of Co nanocrystals to form the nanorods, obtaining the urchin-like CoCu nanocomposites. The catalytic performance in selective hydrogenolysis of glycerol to propanediols proposed that the CoCu urchin-like nanocomposites was superior to the Co nanowires possibly due to that the synergistic effect between Co and Cu component promoted conversion of glycerol and obtained the higher propanediol yields based on the specific surface areas of the catalysts

Efficient Hydrogenolysis of Guaiacol over Highly Dispersed Ni/MCM-41 Catalyst Combined with HZSM-5

A series of MCM-41 supported Ni catalysts with high metal dispersion was successfully synthesized by simple co-impregnation using proper ethylene glycol (EG). The acquired Ni-based catalysts performed the outstanding hydrogenolysis activity of guaiacol. The effects of the synthesis parameters including drying temperature, calcination temperature, and metal loading on the physical properties of NiO nanoparticles were investigated through the use of X-ray diffraction (XRD). The drying temperature was found to significantly influence the particle sizes of NiO supported on MCM-41, but the calcination temperature and metal loading had less influence. Interestingly, the small particle size (≤3.3 nm) and the high dispersion of NiO particles were also obtained for co-impregnation on the mixed support (MCM-41:HZSM-5 = 1:1), similar to that on the single MCM-41 support, leading to excellent hydrogenation activity at low temperature. The guaiacol conversion could reach 97.9% at 150 °C, and the catalytic activity was comparative with that of noble metal catalysts. The hydrodeoxygenation (HDO) performance was also promoted by the introduction of acidic HZSM-5 zeolite and an 84.1% yield of cyclohexane at 240 °C was achieved. These findings demonstrate potential applications for the future in promoting and improving industrial catalyst performance

Simply packaging Ni nanoparticles inside SBA-15 channels by co-impregnation for dry reforming of methane

The highly dispersed Ni nanoparticles inside SBA-15 channels (Ni@ SBA- 15) were synthesized simply by co-impregnation using ethylene glycol (EG). During co-impregnation, the EG additive in the metal nitrate aqueous solution could successfully deliver and package the nickel species into the channels of mesoporous SBA-15. The characterization results suggest that drying after impregnation plays a critical role in the distribution of the precursor. Compared with conventional impregnation, redistribution and agglomeration of the Ni precursor were efficiently avoided due to the lower surface tension and high viscosity of the concentrated solution during drying, and super-small Ni nanoparticles with higher dispersions and narrow particle size distributions were predominantly confined over the internal surface of mesoporous channels instead of its external surface. The Ni@ SBA- 15 catalyst using co-impregnation demonstrated excellent sintering-resistance and stability in the dry reforming of methane due to its strong metal-support interaction and the confined location of Ni nanoparticles

A simple method to prepare highly active and dispersed Ni/MCM-41 catalysts by co-impregnation

A simple method for preparing highly active and dispersed supported metal catalysts was developed by co-impregnation. Compared with conventional wetness impregnation, addition of moderate ethylene glycol into the metal nitrate aqueous solution could enhance interaction with MCM-41 surface, resulting in formation of very small NiO particle size (3.5 nm) and high dispersion of the active phase. The Ni/MCM-41 catalysts using co-impregnation exhibited excellent catalytic performance for low temperature hydrogenation of naphthalene with 100% conversion at 55 degrees C, which could rival the activity of commercial Raney Ni catalyst. The obtained catalysts were characterized by XRD, TEM, TG-DSC, FT-IR, BET and TPR. (C) 2013 Published by Elsevier B.V

Promotion of Ni/MCM-41 Catalyst for Hydrogenation of Naphthalene by co-Impregnation with Polyols

The activities of nickel supported on MCM-41 catalysts, prepared by co-impregnation with polyols (ethylene glycol, glycerol, xylitol, sorbitol and glucose), were investigated by hydrogenation of naphthalene. Compared with the conventional wetness impregnation, addition of moderate polyols into the metal nitrate aqueous solution could enhance interaction with support surface, resulting in formation of very small NiO particle size (<5 nm), high dispersion of the active phase and significant catalytic activity. Particle size of Ni~0 decreased from 36.1 nm to below 5 nm; meanwhile the complete hydrogenation of naphthalene was dependent on the Ni~0 particle size. The hydrogenation activities of the catalysts prepared by co-impregnation with polyols were very high with 100% conversion even at low temperature of 55 oC

乙二醇促进制备高分散的cosio2催化剂及其催化乳酸乙酯转化为12丙二醇的气相加氢活性

Highly dispersed Co catalysts supported on SiO_2 were prepared in the presence of ethylene glycol（EG） by co-impregnation and tested in the vapor-phase hydrogenolysis of ethyl lactate to 1,2-propanediol.The synthesis parameters of Co metal loading,ratio o

乙二醇促进制备高分散的Co/SiO_2催化剂及其催化乳酸乙酯转化为1,2-丙二醇的气相加氢活性

Highly dispersed Co catalysts supported on SiO_2 were prepared in the presence of ethylene glycol（EG） by co-impregnation and tested in the vapor-phase hydrogenolysis of ethyl lactate to 1,2-propanediol.The synthesis parameters of Co metal loading,ratio o

Effect of Calcination Temperature on Catalytic Activity and Textual Property of Cu/HMOR Catalysts in Dimethyl Ether Carbonylation Reaction

The effect of calcination temperature on the catalytic activity for the dimethyl ether (DME) carbonylation into methyl acetate (MA) was investigated over mordenite supported copper (Cu/HMOR) prepared by ionexchange process. The results showed that the catalytic activity was obviously affected by the calcination temperature. The maximal DME conversion of 97.2% and the MA selectivity of 97.9% were obtained over the Cu/HMOR calcined at 430 ±C under conditions of 210 ±C, 1.5 MPa, and GSHV of 4883 h~(-1). The obtained Cu/HMOR catalysts were characterized by powder X-ray diffraction, N_2 absorption, NH_3 temperature program desorption, CO temperature program desorption, and Raman techniques. Proper calcination temperature was effective to promote copper ions migration and diffusion, and led the support HMOR to possess more acid activity sites, which exhibited the complete decomposing of copper nitrate, large surface area and optimum micropore structure, more amount of CO adsorption site and proper amount of weak acid centers