Evaluation of calcined hydrocalumite-type materials as supports of CoMo and NiMo for thiophene hydrodesulfuration reaction

Abstract

A hydrocalumite-type material (HC) was synthesized by the co-precipitation method, mixing Ca and Al nitrate solutions in a NaOH solution (pH ≅ 11). This solid was characterized by using different physico-chemical techniques such as: Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), temperature programmed reduction (TPR) and BET surface area measurements. Then, a portion of as-synthesized solid was calcined at 420 ºC (HC 420). Both calcined and pristine solids were impregnated with Mo (15% w/w as MoO 3 ). Ni or Co was also impregnated on Mo/HC or Mo/HC 420 in 1(Co or Ni):3 (Mo) atomic ratios to get catalytic precursors. These solids were also characterized by the above mentioned techniques. Catalytic precursors were tested in the thiophene hydrodesulfuration reaction at 280 ºC and atmospheric pressure. Cobalt promoted catalysts were more active than those promoted with Ni. However, thiophene conversions were lower than that of a conventional CoMo/γ-Al 2 O 3 catalyst.

Al2O3–CaO macroporous ceramics containing hydrocalumite-like phases

“…Moreover, the absorption bands at 789 cm -1 , 533 cm -1 and 428 cm -1 for the hydrocalumite are related to stretching vibrations of OH-groups linked to metal elements [17,27]. Therefore, despite not showing some absorption bands in the range of 789 cm -1 and 428 cm -1 , the DRIFT results pointed out that phases with hydrocalumite structure were formed in both CL370+CaCO3 and CL370+Ca(OH)2 compositions.…”