Surface properties of ZrO2 dispersed on SiO2

Physicochemical and Catalytic Properties of NiSO4/CeO2-ZrO2Catalyst Promoted with CeO2for Acid Catalysis

“…In general, for the metal oxides modified with sulfate ion followed by evacuation above 400 o C, a strong band assigned to S=O stretching frequency is observed at 1390-1370 cm −1 . 23,24 In a separate experiment infrared spectrum of selfsupported 10-NiSO 4 /1-CeO 2 -ZrO 2 after evacuation at 500 o C for 1 h was examined. As shown in Figure 1, an intense band at 1391 cm −1 accompanied by broad and intense bands below 1250 cm −1 was observed due to the overlapping of the CeO 2 and ZrO 2 skeletal vibration, indicating the presence of different adsorbed species depending on the treatment conditions of the sulfated sample.…”

“…As Figure 8(a) shows, the intense band at 1391 cm −1 after evacuation at 500 o C is assigned to the asymmetric stretching vibration of S=O bonds having a high double bond nature. 24,30 However, the drastic shift of the infrared band from 1391 cm −1 to a lower wavenumber(not shown due to the overlaps of skeletal vibration bands of CeO 2 -ZrO 2 ) after ammonia adsorption [ Figure 6(b)] indicates a strong interaction between an adsorbed ammonia molecule and the surface complex. Namely, the surface sulfur compound in the highly acidic catalysts has a strong tendency to reduce the bond order of S=O from a highly covalent double-bond character to a lesser double-bond character when a basic ammonia molecule is adsorbed on the catalysts.…”

“…Namely, the surface sulfur compound in the highly acidic catalysts has a strong tendency to reduce the bond order of S=O from a highly covalent double-bond character to a lesser double-bond character when a basic ammonia molecule is adsorbed on the catalysts. 24,30 Acids stronger than H o ≤ −11.93, which corresponds to the acid strength of 100% H 2 SO 4 , are superacids.…”

“…Consequently, NiSO 4 /1-CeO 2 -ZrO 2 catalysts would be solid superacids, in analogy with the case of metal oxides modified with a sulfate group. 5,24,36 This superacidic property is attributable to the double bond nature of the S=O in the complex formed by the interaction between NiSO 4 and 1-CeO 2 -ZrO 2 .…”

Characterization of NiSO4Supported on Fe2O3and Catalytic Properties for Ethylene Dimerization

“…Reaction products were analyzed by gas chromatography with a VZ-7 column at room temperature. In general, for the metal oxides modified with sulfate ions followed by evacuation above 400 o C, a strong band 33,34 assigned to S=O stretching frequency is observed at 1390-1360 cm…”