Ni-Alumina Dry Reforming Catalysts: Atomic Layer Deposition and the Issue of Ni Aluminate

•Ni/Al2O3 stability for CH4 dry reforming (DRM) higher with alumina ALD overcoats.•Rates of Ni sintering and C deposition lower on overcoated than uncoated catalyst.•Nickel aluminate phase unstable under DRM conditions used.•Slow reduction of NiAl2O4 cause of gradual catalyst activity increase.•Proposed to stabilise alumina overcoated Ni based catalysts by avoiding NiAl2O4.