Influence of reduction conditions on the structure-activity relationships of NaNO3-promoted Ni/MgO dual function materials for integrated CO2 capture and methanation

•Impacts of reduction conditions on ICCU-M performance of AMS-NM-X-Y were investigated.•High temperature and H2 concentration favored NiO reduction and oxygen vacancy formation.•High reduction temperature resulted in AMS loss and decay in CO2 uptakes.•High H2 concentration could be an alternative strategy to high temperature for NiO reduction.•CO2 adsorption and methanation kinetic performance of AMS-NM-X-Y was evaluated.