Efficient Tuning of Surface Nickel Species of the Ni-Phyllosilicate Catalyst for the Hydrogenation of Maleic Anhydride

The rational design of catalyst is vital in the hydrogenation of maleic anhydride (MA) to chemicals, for its special construction with one C = C bond and two C = O bonds. Herein, the catalyst with nickel nanoparticles (NPs), inlaid nickel phyllosilicate (Ni-PS) featured with proper Ni-0 and assembled Lewis acid sites, is proposed for the efficient hydrogenation of MA to succinic anhydride (SA) and gamma-butyrolactone (GBL). The remarkable efficiency is attributed to the synergistic effect between the surface Ni-0 and the Lewis acid sites induced from partially reduced Ni and coordinatively unsaturated Ni(II) in Ni-PS. The acid sites adsorb and activate the C = C and C = O groups, whereas the Ni facilitates the H-2 decomposition. In situ XPS demonstrated that the ratio of surface Ni-0 and Lewis acid sites can be modulated effectively by changing the Ni/Si molar ratio in the catalysts, and they exhibited significantly different catalytic activity in the hydrogenation of MA. Under a lower temperature, the hydrogenation activity of MA to SA linearly increases by increasing the Lewis acid sites surface area when the accessible Ni-0 surface area is enough, whereas it is primarily affected by the Ni-0 sites under high temperature for the hydrogenation of MA to GBL.