Role of in situ (in contact with biomass) and ex situ (in contact with pyrolysis vapors) transition metal catalysts on pyrolysis of cherry pits

•Ex-situ catalytic upgrading reduces O/C ratio of bio-oil when compared to in-situ.•When acting only on the vapor phase, manganese fragments pyrolysis gas to a greater degree.•In-situ upgrading reduces the number of observable functional groups in the bio-oil.•Catalyst location has little impact on the product phases generated.