Carbon dioxide refinery: critical review of valorisation processes into sustainable higher alcohol production

Abstract

The CO₂ refinery concept is vital for achieving net zero emission goal. Transforming CO₂ into fuels, chemicals, and materials offers an encouraging and profitable solution alongside renewable energy and green hydrogen. Higher alcohols (C₂–C₄ alcohols) are essential in modern society and extensively used in the production of chemicals, solvents, and fuels. Even though bioethanol production from biomass is established, transforming CO₂ into higher alcohols presents a more sustainable and green initiative. Nevertheless, challenges like breaking the stable C–O bond in CO₂ and regulating C–C coupling in higher alcohol synthesis (HAS) make the process unfavourable. The present review highlights all the advancements in CO₂ hydrogenation for higher alcohol production, focusing on both the direct and indirect routes, catalytic systems, and efficient processes in both batch and fixed-bed reactors. Addressing these challenges will guide the development of efficient catalysts and processes for sustainable CO₂ utilization, supporting a greener future.