The reaction mechanism of methylcyclopentane (MCP) ring-opening on Rh catalysts (the participation of each intermediate in further hydrogenolysis versus their desorption) was studied on a special series of Rh(Ge)/Al2O3 catalysts. These were obtained by wet impregnation and adding different amounts of Ge by anchoring of Ge(n-C4H9)(4) on the surface of Rh with preadsorbed hydrogen. As shown earlier [Appl. Catal. A: Gen. 245 (2003) 15], low amounts of Ge were deposited selectively on low-Miller-index microfacets, whereas excess use of Ge(n-C4H9)(4) caused statistical deposition on Rh. This difference induced also alterations in the classical ring-opening pattern: the sample with randomly located Ge behaved like the Parent catalyst with dispersion of 80%. Each ring-opening intermediate hydrogenolyzed further nearly to the same extent; the ring-opening product distribution (ROPD) showing thus no variation as a function of reaction conditions. The catalyst with selective Ge deposition followed, however, the pattern of a sintered sample: the surface intermediate of 2-methylpentane underwent preferential hydrogenolysis to smaller fragments. Thus, changing the position of Ge deposits (without modifying the particle size) induced changes in the prevailing reaction route. (C) 2003 Elsevier B.V. All rights reserved.