Experimental and DFT studies on diesel-steam-reforming to hydrogen over a bimetallic Rh–Ni-based MgO-Al2O3 microsphere catalyst

•Monodisperse microsphere catalyst with bimetallic Rh–Ni supported on the surface of MgAl2O4.•Rh-doping promotes Ni dispersion and leads to the formation of Rh–Ni close interaction and alloy.•Rh–Ni catalyst outperforms Ni and Rh in activity, stability, resistance of sintering and coking.•The weakened adsorption of CH2O*, CHO*, O* on Rh–Ni(111) enhances hydrocarbons steam reforming.•Barrier of rate-limiting step (CH2*+O*→CH2O*) over Rh–Ni(111) is lower than Ni(111) and Rh(111).