The invention provides a catalyst system and method for the deoxygenation of hydrocarbons, such as bio-oil, using a sulphide-sulfate or an oxide-carbonate (LDH) system. The invention extends to a pyrolysis process of a carbonaceous bio-mass wherein a first combustion zone is carried out in one or more combustion fluidised beds in which a particulate material including chemically looping deoxygenation catalyst particles is fluidised and heated, and a second pyrolysis zone carried out in one or more pyrolysis fluidised beds in which the hot particles, including the catalyst particles, heated in the combustion zone are used for pyrolysis of the bio-mass, said combustion zone being operated at a temperature of from 250° C. to 1100° C., typically around 900° C., and the pyrolysis zone being operated at a temperature of from 250° C. to 900° C., typically 450° C. to 600° C., said catalyst particles being oxygenated in the pyrolysis zone in the presence of oxygenates in the pyrolysis oil and regenerated in the combustion zone either by calcining to drive off the carbon oxides, such as CO2, or by reduction to its form which is active for deoxygenation of the pyrolysis oil.