Influences of Al modification on the properties and catalytic performance of SBA-15 molecular sieves in hydrocracking

SBA-15 molecular sieves were modified with Al by adjusting pH value and post-grafting synthesis and used as the catalysts for hydrocracking. The new mesoporous materials were characterized by XRD, ²⁷Al NMR, N₂ adsorption and desorption and NH₃-TPD. The results showed that Al-SBA-15 is successfully obtained through synthesis via adjusting pH value; it exhibits an ordered hexagonal mesoporous structure and well hydrothermal stability. Al modification is able to enhance the amount of surface acid sites of SBA-15, which induces the Al-SBA-15 catalyst with high selectivity to middle distillate for hydrocracking.