The deposition of heavy metals on a cracking catalyst reduces not only the catalyst activity but also its selectivity. Aluminum diacetate synthesized from gibbsite can be used as an active matrix to reduce the harmful effects caused by such metals. The alumina obtained by thermal decomposition shows either a monomodal or a bimodal pore size distribution, and a peculiar pore shape. When present in a cracking catalyst, this alumina modifies its texture enabling large molecules to access the inner components. The catalyst can thus achieve a better bottoms conversion, and coke formation is reduced. Also, the active matrix minimizes vanadium catalyst interactions by selectively sorbing migrating vanadium compounds. Nickel is also passivated since its dehydrogenation activity is suppressed. Hence, nickel-impregnated catalysts show an improved selectivity. Thus, aluminum diacetate containing catalysts appear to have the necessary texture and metal tolerance to crack residual oil and may offer cost advantages over conventional cracking catalysts.