Active Centers of Catalysts for Higher Alcohol Synthesis from Syngas: A Review

Abstract

The gradual depletion of oil resources and the necessity to reduce greenhouse gas emissions portray a concerning image of our contemporary security of liquid transportation fuels in the event of a global crisis. Despite a vast amount of natural gas resources we have and the huge economic incentive, the conversion for gas-to-liquid fuels or chemicals is still very limited due to the high technological complexity and capital cost for facilities. However, with the anticipated depletion of liquid petroleum and the soaring price of crude oil, the conversion of natural gas to liquid feedstock or fuels will become more and more important. Higher alcohols are important feedstocks for chemical and pharmaceutical industries and have wide applications as the potential fuel additives or hydrogen carriers for fuel cells for clean energy delivery. There is a long-standing interest for higher alcohols synthesis from syngas, an important Fischer-Tropsch technology for natural gas conversion. The purpose of this article is to provide readers with an extensive account on catalytic higher alcohols synthesis from syngas using various catalysts, reviewed from a unique perspective-clarification of the active centers and reaction pathways. In light of the different sources to provide the active centers, three major classes of catalysts in terms of monometallic, bimetallic and trimetallic /multimetallic catalysts have been systemically reviewed and their respective performances are carefully compared. Finally, future works proposed to improve the catalyst design are described.