Offering a new option to valorize hen manure by CO2-assisted catalytic pyrolysis over biochar and metal catalysts

•Hen manure (HM) was valorized into biochar catalyst and syngas.•Catalytic pyrolysis of HM using HM-derived biochar signified syngas formation.•CO2-assisted pyrolysis expedited CO production via gas phase reactions.•HM biochar was catalytically active with almost half performance of Ni catalyst.