h i g h l i g h t s g r a p h i c a l a b s t r a c tCeeLa solid solution supported Rh catalyst shows high activity for H 2 production. The catalyst also shows low CO selectivity and good stability. The performance of the catalysts varied depending on urea/metal ratio during preparation.a r t i c l e i n f o is prepared by a co-precipitation method using urea as a precipitant, with varying urea/metal molar ratio (N). The supported rhodium catalysts are then prepared by an impregnation method for use in hydrogen production from oxidative steam reforming (OSR) of ethanol. X-ray diffraction and Raman spectra results confirm the formation of CL, and the crystal structures of these catalysts are not very sensitive to the urea/metal molar ratios (N ¼ 5e15). However, the surface area and reducibility of the Rh/CL-N catalysts decrease monotonically with increasing N. During the OSR process, a similar tendency is also observed for ethanol conversion and hydrogen selectivity. Among the catalysts tested, Rh/CL-5 shows the best catalytic performance, achieving >97% ethanol conversion at 300 C with H 2 yield rate of 210 mmol g-cat À1 s À1 . At 450 C, its hydrogen selectivity reaches 117%, with no observable change after 72 h aging.