Mesoporous nanocrystalline TiO2 supported metal (Cu, Co, Ni, Pd, Zn, and Sn) catalysts: Effect of metal-support interactions on steam reforming of methanol

Abstract

a b s t r a c tMesoporous TiO 2 supported Cu, Co, Ni, Pd, Sn and Zn catalysts (M-TiO 2 ) were synthesized using facile onestep synthesis method and were characterized using BET, XRD, TGA-DSC, TEM, SEM-EDX, ICP-OES, and H 2 -TPR studies. The catalysts were further tested for steam reforming of methanol (SRM) to investigate their comparative catalytic performance. Depending on the nature of the metal component, the catalysts exhibited surface area, pore sizes, and TiO 2 crystallite sizes in the range of 99-309 m 2 /g, 2.63-4.69 nm and 6.8-17.2 nm, respectively. N 2 -physorption, TGA-DSC and XRD analysis demonstrated that the presence of metal in the TiO 2 matrix stabilized the mesoporous structure by hindering the crystal growth during heat treatment and thereby preventing the collapse of porous structure. Furthermore, the characterization of 5-20% Zn-TiO 2 catalysts indicated that there exist an optimum Zn loading to obtain highest surface area which was found to be 15% in the present study giving a high surface area of ∼258 m 2 /g. This was consistent with the SRM studies where the activity increased up to 15% and then decreased significantly with further increase in Zn loading to 20%. The results of the SRM studies coupled with extensive TPR analysis of different M-TiO 2 catalysts suggest that the specific metal-support interactions play a crucial role in controlling its performance on H 2 production. The SRM activity order for different metals incorporated in mesoporous TiO 2 was observed to be: Pd > Ni > Zn > Co » Cu » Sn. The Zn-TiO 2 catalyst showed the lowest CO selectivity among the different catalysts studied.

NOx Removal Performance Optimization of NiMnTi Mixed Oxide Catalysts by Tuning the Redox Capability

“…Four peaks were detected for Ni 3 Mn 1 Ti 1 -LDO catalysts, which might be connected with the reduction of Mn 4 + À Mn 3 + À Mn 2 + , Ni 3 + À Ni 2 + À Ni 0 and Ti 4 + À Ti 3 + . [19,49] With the calcination temperature increasing, the location of reduction peaks shifted to higher temperature zones, which might be possibly related to the change of phase composition at higher calcination temperature, such as the generation of anatase TiO 2 , rutile TiO 2 and NiTiO 3 [50] in good accordance with XRD results. The phase composition of Ni 3 Mn 1 Ti 1 -LDO catalysts had a direct impact on interaction among manganese, nickel and titanium species, and further affected the reducibility.…”

Methanol total oxidation as model reaction for the effects of different Pd content on Pd-Pt/CeO2-Al2O3-TiO2 catalysts

“…The pore sizes of all the catalysts concentrated on the scope range from 5 to 15 nm. The shape of these isotherms showed a type IV isotherm (IUPAC classification) with a H4 hysteresis loop [31] located at 0.40 < P/P 0 < 1.0. All the features indicated that these catalysts belonged to typical mesoporous materials.…”

Benzyl alcohol oxidation with Pd-Zn/TiO2: computational and experimental studies

“…However, three strong reduction peaks are seen at temperatures of 289, 329 and 577°C. The peak around 577°C is ascribed to the reduction of Ti 4+ ions [31]. The two peaks at lower temperature are believed to be a result of TiO 2 surface reduction.…”