Recent Advances and Perspectives in Catalyst Design for Converting Syngas to Higher Alcohols

Higher alcohol synthesis (HAS) has attracted much attention owing to the wide use of C2+OH as a synthetic fuel, an alternative fuel additive, a hydrogen carrier, and a versatile platform molecule. Using homogeneous and heterogeneous catalysts, HAS can be produced from syngas (H2 and CO) derived from nonfood-based lignocellulosic biomass, oil residues, coal, natural gas, and solid or liquid carbonaceous waste products. Although much effort has been devoted to maximizing the yield of C2+OH using noble- and non-noble-metal catalysts, significant challenges remain in terms of large-scale industrial production. In the past decade, the development of solid catalysts for the efficient production of higher alcohols, from carbon feedstocks, has attracted much interest. In this Review, we focus on the developments in the past decade that have focused on the use of heterogeneous catalysts in HAS. We have reviewed the developments regarding the effect of supports, promoters, Rh-based catalysts, modified methanol synthesis catalysts, modified Fischer–Tropsch (FT) synthesis catalysts, Mo/MoS2-based catalysts, and the generic structural design of catalysts on their catalytic performances in HAS. We have also summarized the use of tandem catalysts that have been used in HAS. Catalyst stability, reaction mechanisms, and density functional theory (DFT) calculations used in HAS studies have also been briefly discussed. Finally, we provide our insights and perspectives on the topic to encourage further exploration in this emerging field.