The effect of catalyst preparation on the performance of alumina-supported ruthenium catalysts I. The impact of catalytic precursor on particle size and catalytic activity

Abstract The effect of preparation method and the choice of metallic precursor on the performance of a series of Ru Al 2 O 3 catalysts were studied. Wet impregnation and incipient wetness were the methods employed; ruthenium nitrosylnitrate and ruthenium trichloride were the reagents. In the latter case, either Ru(III) Ru(IV) chlorospecies or mixtures of Ru(II) hydrazine complexes were the catalytic precursors. The series of Ru Al 2 O 3 catalysts, with metal loadings from 0.7–5% by weight, were subjected to a battery of performance tests: CO temperature-programmed reaction, steadystate CO hydrogenation, and temperature-programmed surface reaction. The methanation activity and carbon deposited during steady-state reaction varied systematically with the dispersion of Ru on the alumina. High rates of methane production were found on catalysts containing a large reservoir of carbon-containing reaction intermediates. The performance of these catalysts depended on the precursor used in their preparation. The effects of weight loading, method of preparation, and variations in the impregnant pH were small within a group prepared from a Common precursor.