The catalytic gasification of biochar was investigated in the presence of a Ni/SiO2 catalyst in a fixed bed reactor with an O-2-steam-CO2 gas feed. The effects of operating temperature, catalyst nickel loading and composition of O-2-steam-CO2 feed gas on biochar carbon conversion and gas products were investigated. The results indicate that the highest biochar carbon conversion could be obtained at approximately 800 degrees C, whilst the 10% Ni/SiO2 catalyst was shown to produce the greatest syngas yields. The presence of O-2 in the feed gas can result in slightly more CO in the gas product, whilst a higher steam content leads to more H-2 in the gas product. The CO2 offered a benefit as an adjusting agent for achieving a desired H-2/CO ratio. No evidence of coke deposition on the catalyst was found under any of the tested conditions. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.