Selective Conversion of Syngas into Higher Alcohols via a Reaction-Coupling Strategy on Multifunctional Relay Catalysts
Xuebin Luan, Ziteng Ren, Xiaoping Dai, Xin Zhang, Jiaxi Yong, Yang Yang, Huihui Zhao, Meilin Cui, Fei Nie, Xingliang Huang
Abstract
Direct conversion of syngas (CO/H2) into higher alcohols is highly desirable but remains challenging due to the low C2+OH selectivity. Herein, an effective strategy was developed through the combination of partially reduced Zn-Cr-Al trinary oxides (ZnCrAlOx) and Mo-based sulfides to significantly raise the alcohol selectivity. The introduction of K on Mo-based sulfides suppresses the acid sites and stabilizes alkoxy species (CHxO*), which greatly enhances the selectivity of alcohols. The close proximity of the two components on the multifunctional relay catalyst ZnCrAlOx|KNiMoS-MMO-5 can effectively promote the migration of reaction intermediates by shifting the DME formation equilibrium on ZnCrAlOx, achieving an alcohol selectivity of 60.4% with more than ∼72.7% of C2+OH selectivity in alcohols under a CO conversion of 9.8%, and significantly improves the turnover frequency (TOF) of C2+OH (71.9 h–1). A plausible reaction mechanism is also proposed on the multifunctional relay catalyst ZnCrAlOx|KNiMoS-MMO-5. This work provides a promising avenue to improve the selectivity of higher alcohols through a multifunctional relay catalyst affording multiple types of active sites.