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A novel in-situ synthesis method was introduced to prepare Ni-Mg-AI-LDHs catalyst on γ-A1203,which were evaluated by dry reforming of methane reaction.A series of LDHs catalysts were obtained by disposing Ni-Mg-AI-LDHs/γ-A12O3 with different pretreatments.The catalytic properties of these catalysts were investigated in activity and stability test of reforming reaction.Ni-Mg-AI-LDHs/γ-Al2O3 directly calcinated and reduced by H2/Ar atmospheric cold plasma jet presented the best catalytic performances.It is worth to note that an unfulfilling catalytic properties was obtained by the catalyst which Ni-Mg-AI-LDHs/γ-A1203 calcinated at 500℃ for 3 hours and then reduced by plasma.Interesting,NiA1204 spinels were found on latter catalyst after activity test,which detected by XRD.Without any calcination and reduction,Ni-Mg-AI-LDHs/γ-Al2O3 itself also showed a certain extent activity in CO2 reforming of CH4,like a catalyst with only calcinaton of Ni-Mg-Al-LDHs/y-Al2O3 at 500 ℃ for 3 hours.Besides,the structure-function relationships of catalysts were investigated with characterization of XRD,TEM,N2-adsoption and TG technology.The LDHs/γ-Al2O3 catalyst which exhibited both small particle size and uniform dispersion of active nickel crystal grain,demonstrated high activity and excellent resistance to carbon accumulated on the catalyst surface.A comparison has also been made between supported Ni-Mg-AI-LDHs/γ-AL2O3 and unsupported Ni-Mg-Al-LDHs catalysts,the former showed better catalytic performances which were due to the stronger mechanical strength as well as more proper specific surface provided by γ-Al2O3.