Synthesis of alumina by microwave-assisted combustion method using low fuel content and its use as catalytic support for dry reforming of methane

Abstract

Alumina powders with high specific surface area (>200 m2g-1) were obtained quickly, easily and using only aluminum nitrate and urea (as fuel) through the microwave-assisted combustion method applying low power (450 W) and low fuel content. The powders obtained were calcined at temperatures of 550, 750 and 950 °C. The X-ray diffraction and Fourrier Transform Infrared (FTIR) results indicate that γ-Al2O3 was formed at temperatures of 550 and 750 °C, while the α and γ phases were identified in calcined alumina at 950 °C. The increase in calcination temperature strongly influenced the specific surface area and the pore size distribution, however no effect on the pore diameter was observed. The Al2O3 powder calcined at 550 °C was evaluated as catalytic support due to its most appropriate textural properties. The catalyst Ni/Al2O3 (Ni-A550) was prepared by wet impregnation method and calcined at 550 °C/3 h. The physical-chemistry properties were evaluated by X-ray diffraction, temperature programmed reduction and scan electron microscopy techniques. The results show that the Ni-A550 have high conversion of CH4 and CO2 and good H2 yield using a gas hourly space velocity (GHSV) of 72 L g−1 h−1. Therefore, the synthesized Al2O3 presents as a potential catalytic support material.