Synthesis, morphology control, and application of hollow Al2O3 spheres in the steam methane reforming process

This research focuses on controlling the morphology and crystalline phase of hollow Al2O3 spheres as a supporting material of Ni-based catalysts for the first time, which is then applied as a catalyst of high-temperature steam methane reforming (SMR) process. For this purpose, the effects of hydrothermal time, the concentration of alumina salt, and calcination temperature on the structure of support are investigated and adjusted and then loaded with 15–25 wt.% Ni contents. The morphology of synthesized hollow alumina samples and 20Ni/H-Al2O3 catalyst before and after reaction are characterized using XRD, FESEM, TEM, H2-TPR, CO2-TPD, EDX, FTIR, N2 adsorption/desorption, and mapping techniques. The hydrothermal time of 72 h, calcination temperature of 800 °C, and alumina salt concentration of 1.00 M resulted in the spherical morphology of hollow Al2O3 with 236.26 m2/gr surface area and high crystallinity. Among different Ni loadings, 20Ni/H-Al2O3 had the highest CH4 conversion of 87.75% and H2 yield of 92.09% at 700 °C. This catalyst also depicted stable performance during 12 h SMR reaction at 700 °C with low carbon deposited contents.