Tri-metallic and ternary oxide structures were prepared, characterised and tested for two fixed-bed catalytic applications: the reforming of methane with steam and CO2; and for conditioning the gas produced by biomass steam gasification in a fluidised bed of olivine particles, with the aim of drastically reducing high and low molecular weight hydrocarbon concentrations in the product gas, Methane conversions higher than 90% were achieved for a synthetic gas feed mixture (similar of that produced in biomass gasification) using the catalyst formulation LaNi0.3Fe0.7O3 at 800degreesC: the space time under reaction conditions was 0.05 s, and no carbon was formed for reaction periods of up to 150 It. The catalyst contained in a secondary fixed-bed reactor placed after the gasifier was able to convert about 90% by weight of the tar present in the raw gas at 800degreesC: the space time under reaction conditions was 0.45 s, during which time no coke formation was observed on the catalyst surface.