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Alkaline-Etched NiMgAl Trimetallic Oxide-Supported KMoS-Based Catalysts for Boosting Higher Alcohol Selectivity in CO Hydrogenation

Yong, Jiaxi, Luan, Xuebin, Dai, Xiaoping, Zhang, Xin, Yang, Yang, Zhao, Huihui, Cui, Meilin, Ren, Ziteng, Nie, Fei, Huang, Xingliang
ACS applied materials & interfaces 2019 v.11 no.21 pp. 19066-19076
acidity, alcohols, alkalinity, carbon, carbon monoxide, catalysts, cetyltrimethylammonium bromide, hydrogenation, molybdenum, texture
The acidity/alkalinity and structural properties of NiMgAl trimetallic oxides (MMOs) can be effectively modulated by the alkaline-etching process with various etching times, which are further used as a support to prepare KMoS-based catalysts through the cetyltrimethylammonium bromide-encapsulated Mo-precursor strategy. The enriched surface anion groups in alkaline-etched MMO affect the textural properties, metal-support interaction, and sulfidation degree of the as-synthesized KMoS-based catalysts. As a result, KMoS-based catalysts using alkaline-etched MMO as supports effectively enhance the reducibility and dispersion of Mo species, which exert a positive influence on higher alcohol synthesis (HAS) performance in CO hydrogenation. A proper balance between acidity/alkalinity and structural properties in K, Mo/MMO-x catalysts can significantly enhance the alcohol selectivity in HAS from 55 to 65% (carbon selectivity). The formation of C₂⁺ alcohols can be boosted by adol condensation with optimal acidic/basic properties via suppressing the acidity and increasing the amount of basic sites. The alkaline-etching process also significantly improves the space time yield of C₂⁺ alcohols over unit mass of molybdenum.