Influence of organic additives on the properties of impregnation solutions and on nickel oxide particle size for Ni/Al2O3 catalysts

Oxidative CO 2 reforming of methane over stable and active nickel-based catalysts modified with organic agents

“…7 curves b 1 -d 2 ), two other bands were observed at 1560 and 1720 cm À1 . The former was attributed to asymmetric vibration of COO À , while the latter was the characteristic of the protonated COOH groups [51]. The IR bands associated to the symmetric vibrations of carboxylate and carboxylic groups around 1417 cm À1 were merged with the broad absorption band from nitrate ions at 1360 cm -1 .…”

“…For low CA/Ni 2þ molar ratio (curve b 1 , b 2 ), no protonated COOH group was observed. This IR vibration intensity increased with the CA loading, since CA contains three COOH functional groups and only two of them are needed to react with Ni 2þ during the preparation of the solution [51].…”

“…The reduction temperature increased to 480 C, which was presumably due to the smaller NiO grains making diffusion effects of the reducing gas more pronounced. The TPR profile revealed that small nickel oxide grains were present on the silica support via the addition of CA, which acted as an organic additives [51] through occasional introduction into the first-sphere of coordination of Ni 2þ , or through hydrogen-bonding into the second sphere of coordination. This resulted in an increase of the solution viscosity, so that drying this solution would further increase the viscosity and form an amorphous deposit on the silica surface.…”

Dielectric barrier discharge plasma for preparation of Ni-based catalysts with enhanced coke resistance: Current status and perspective

“…Ni-based catalysts have been extensively applied for CO methanation, CO 2 or stream reforming of methane, partial oxidation of methane, water gas shift reaction, and others because of the high activity, low cost, and plentiful resources of nickel [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. The catalytic performance of Ni catalysts in CO or CH 4 reactions has been widely studied [21][22][23][24][25][26][27][28][29][30].…”

Application of POSS Nanotechnology for Preparation of Efficient Ni Catalysts for Hydrogen Production

“…In order to obtain a high dispersion state for Ni active components, the addition of organic agents such as poly(N-vinyl-2-pyrrolidone) (PVP) [54], citric acid [55], sorbitol or glucose [56] into impregnation solution is made. For example, the application of glucose additive allows decreasing of the average Ni particle size from 7.2 to 3.5 nm in 10 wt.%Ni/Al 2 O 3 samples [56], while the use of poly(N-vinyl-2-pyrrolidone) leads to reduction of the average Ni particle size from 13.0 to 4.3 nm in 5 wt.%Ni/SBA-15 samples [54]. Catalysts prepared with PVP showed better stability in methane reforming.…”