Development of residue coal fly ash supported nickel catalyst for H2 production via glycerol steam reforming

•Valorization of biodiesel waste by-product using coal fly ash (FA)-supported catalysts.•Investigation of activity and stability of different yNi-FAx catalysts in glycerol steam reforming.•Catalytic activity of yNi-FAx catalysts significantly influenced by the physicochemical properties of FAx.•Nepheline provides vacancy sites for better Ni dispersion and intimate Ni-FA interaction, thermostable mullite helps diminish the Ni sintering.•Ni loading affects the Ni0 dispersion and particle size, as well as the metal-FA interactions.