MWCNT-Supported Ni–Mo–K Catalyst for Higher Alcohol Synthesis from Syngas

Abstract

A type of novel MWCNT-supported Ni–Mo–K catalysts for higher alcohol synthesis (HAS) from syngas was developed, which displayed excellent performance for the selective formation of C_1–3-alcohols and DME from syngas. Over the 15%Ni₁Mo₁K_0.05/CNTs catalyst under the reaction conditions of 5.0 MPa and 538 K, the C-based selectivity of (C_1–3-alc. + DME) reached 59.0%, with the corresponding STY of 205 mg h⁻¹ g⁻¹. This value was 1.16 times that of the 35%Ni₁Mo₁K_0.05/AC catalyst with the optimal Ni₁Mo₁K_0.05 loading, and 1.76 times that of the non-supported co-precipitated Ni₁Mo₁K_0.05 host system, under the same reaction conditions. The results of the catalyst characterizations revealed that the CNT-support has strong influence on the chemical states of catalyst via its interaction with the supported Ni–Mo components, leading to the increase of the molar percentage of NiO(OH) and Mo⁴⁺/Mo⁵⁺ (the two kinds of catalytically active surface-species related closely to selective formation of C_1–3-alcohols) and the dramatic decrease of the molar percentage of Ni⁰ and Mo⁰ (the two kinds of catalytically active surface-species related closely to selective formation of hydrocarbons, especially methanation of CO). Moreover, the CNT-support also provided the sp ²-C surface-sites for adsorption-activation of H₂. All these factors contribute to an increase in selectivity of generating C_1–3-alcohols.

Graphical Abstract

A type of novel MWCNT-supported Ni–Mo–K catalysts was developed, which displayed excellent performance for higher alcohol synthesis from syngas. The observed CO conversion and C_1–3-oxygenate selectivity were markedly higher than those of the AC-supported Ni–Mo–K catalyst and non-supported counterpart as reference under the same reaction conditions. The nature of promoter action by CNTs was inquired.