To obtain high yields of hydrogen, a series of Zr x Pr 1-x O y -supported cobalt catalysts were synthesized by the sol-gel method and tested in autothermal reforming (ATR) of acetic acid (HAc) derived from bio-oil. X-ray diffraction, nitrogen physisorption, H 2 -temperature-programmed reduction, and thermogravimetric analysis were conducted to investigate the factors affecting the activities of the catalysts. Over the Co-Zr-Pr-O catalyst, a Zr x Pr 1-x O y solid solution was formed after calcination; meanwhile, the active component of Co 0 was highly dispersed over the solid solution after reduction in hydrogen for 1 h at 700 °C. As a result, stable reactivity was recorded in the ATR process of HAc: the hydrogen yield reached 2.58 mol H2 mol À1HAc with near 100 % HAc conversion, while better resistance to coking was observed.