Acetic acid and phenols are the major components of the condensable by-products in the low temperature de-volatilisation stage of humin during gasification. Catalytic steam reforming of acetic acid using supported Ni on ceria-zirconia mixed oxide prepared via the hydrothermal route is discussed. The influence of steam reforming temperatures, steam/carbon ratios were studied. The catalyst showed high activity and good stability. Furthermore, activity improvement was achieved with multiple redox cycles as relevant to recycling the catalysts. Characterisation of the fresh and used catalyst by various techniques (e.g., LEIS, Raman spectroscopy, TPO/TPR) revealed the modification of metal-oxygen bond on the support under the steam reforming conditions. It in turn improved the oxygen mobility of the catalyst.