Hydrothermal reduction synthesis of K-Ni-Mo-based catalyst and its catalytic performance for higher alcohol synthesis from syngas

Abstract

A series of non-sulfurized K-Ni-Mo-based catalysts with close contact between Ni and K2MoO4 were prepared by hydrothermal reduction for higher alcohol synthesis from syngas. The as-prepared catalysts were characterized by XRD, N2 adsorption-desorption, H2-TPR, HR-TEM, SEM-EDS, XPS, H2-TPD, CO-TPD and CO2-TPD techniques. The results indicate that the introduction of K facilitates the formation of the K2MoO4 phase while brings about a decrease of NiMoO4. It can significantly assist the non-dissociative activation of CO for insertion and subsequently alcohol formation. Moreover, the addition of K increases the surface basicity, which leads to more amount of basic hydroxy groups on the catalytic surface. The catalytic basicity ameliorates the production of alcohols. In particular, the K0.4-Ni-Mo catalyst shows the best catalytic behavior with CO conversion of 19.6%, total alcohol selectivity of 57.8% and C2+ alcohol selectivity in the total alcohols of 66.5 at GHSV of 5000 h−1, 240 °C, and 5 MPa.