Production of ethanol from cellulose in aqueous phase with Pt-Ni@C catalysts

Abstract

A series of Pt-Ni@C catalysts with different Pt/Ni@C mass ratios were prepared using deposition precipitation method. The effect of the loading amounts of Pt on the synthesis of ethanol by cellulose hydrogenation reduction was studied. The structure-performance relationship of the catalyst was clarified. The results showed that the Pt/Ni@C catalyst achieved the complete conversion of high concentration of cellulose under H₂ environment at 200 ℃, 5.5 MPa. When the concentration of cellulose reached 50 g/L, the ethanol concentration in the solution was 13.3 g/L with yield of 31%. The valence state of the Pt species, the ordering degree of carbon and the microstructure of the catalyst were characterized by means of XRD, XPS, Raman and TEM. The Ni atoms wrapped by the carbon layer of the catalyst showed an electron-rich state through electron migration with the surface carbon layer. The electron-negative surface of Pt-Ni@C effectively break the C–O and C–C bonds of the intermediates. Compared with traditional carbon-based catalysts, the amount of surface active sites increased by loading small amount of Pt. The Pt promoted the activation of hydrogen, and the synergistic of electron-rich surface and the trace phosphoric acid led to excellent activity of the Pt-Ni@C.