Nonenzymatic ethanol production in sustainable ways

Ethanol is the most abundant chemical widely used in the fuel additive sector. Currently, it is mainly produced by the fermentation process, but it suffers from low carbon balance and poor reaction efficiency issues. In the past few decades, several promising catalytic methods have been proposed for ethanol production, depending on the available energy resources, technology development, and government policy. Herein, the catalytic pathways for ethanol production from petroleum, coal, natural gas, CO₂, and biomass in more sustainable ways are introduced. Specifically, the most crucial elementary steps in these catalytic pathways are reviewed and discussed, and key factors determining the feasibility of these catalytic reactions are listed, providing an all-around overview on the development of ethanol production in the near future. In the last section, an outlook was provided to highlight the challenges and opportunities for ethanol production and applications in more green and sustainable catalytic manners.