Advances in Catalysis for Syngas Conversion to Hydrocarbons

Syngas, a mixture of CO and H2 (CO/H2), is a key platform for the utilization of nonpetroleum carbon resources such as natural gas or shale gas and coal. Syngas can also be produced from renewable carbon feedstocks such as biomass and even CO2. A variety of products including hydrocarbons and oxygenates, which can be fuels and chemicals, may be produced from syngas. The catalytic transformation of syngas into value-added products is the core of C1 chemistry. This review highlights advances in the past decade in catalytic conversions of syngas into hydrocarbons with an emphasis on selective formations of C5 + hydrocarbons, which are mainly used as liquid fuels, and lower (C2–C4) olefins, key building-block chemicals. Since CO2 is also contained in syngas from some resources, the catalytic hydrogenation of CO2 to hydrocarbons will also be briefly described. Fischer–Tropsch synthesis is a well-established process for syngas to hydrocarbons, but many fundamental aspects remain unclear because of the complexity of the reaction. The products of Fischer–Tropsch synthesis usually follow the Anderson–Schulz–Flory distribution, which is very wide and is nonselective for a target product such as liquid fuels or lower olefins. This article highlights recent advances in understanding the active phase of Fischer–Tropsch catalysts and in designing efficient catalysts using new materials. Furthermore, this article pays particular attention to the breakthrough in the selectivity control, which is the most important challenge for scientific research in syngas chemistry. Besides insights into various factors determining product selectivity as well as activity, we will also discuss emerging methodologies and strategies for the selective conversion of syngas into a specific range of hydrocarbons.