The catalytic activity of Rh for the partial oxidn. of methane to syngas can be markedly affected by interfacing polycryst. Rh films with a dispersed TiO2 interlayer deposited on YSZ. High CO selectivity (near 97%) can be reached in wide range of CH4:O2 ratio at 550 Deg. The obsd. modification of catalytic activity and selectivity towards CO and H2 prodn. over Rh interfaced with interlayer of TiO2 is related to the lowered stability of surface Rh oxide against redn. to metallic Rh. The phenomenon may be interpreted either by electronic type strong metal-support interactions or by self-driven wireless electrochem. promotion mechanism. [on SciFinder (R)]