Heterogeneous Catalysis for the Valorization of CO₂: Role of Bifunctional Processes in the Production of Chemicals

Abstract

Carbon dioxide is an abundant carbon feedstock, and there exists a sustained interest in methods for its utilization. At the moment, several routes that rely on the use of renewable energy for the valorization of CO2 are being considered, with a strong emphasis on fully electrocatalytic routes. In this perspective, we highlight the role that heterogeneous catalysis may play in hybrid processes in which H2 is obtained via electrolysis and CO2 valorized in a second, dark step. Targeting high selectivity to value added products (olefins and aromatics), we cover CO2 to chemicals routes that involve cascade multifunctional processes. In doing so, we highlight the main advantages of this approach along with the most important challenges and remaining questions.

Tandem Conversion of CO2 to Valuable Hydrocarbons in Highly Concentrated Potassium Iron Catalysts

“…[6] The transformation of CO 2 into olefins generally proceeds through a modified Fischer-Tropsch (FTS) process using synthesis gas over an iron catalyst. [7][8][9] Here, CO 2 is first transformed into CO via a reverse water-gas shift (RWGS) reaction and further converted to olefins via a conventional FTS process. The main drawback of this route lies in the first hydrogenation of CO 2 to CO.…”

Coated sulfated zirconia/SAPO-34 for the direct conversion of CO2to light olefins

“…[4][5][6] Among all possible alternatives, the direct thermocatalytic conversion of CO 2 using electrochemically generated H 2 holds great promise. 7,8 The combination of several catalytic functions into one single reactor has been shown capable of converting CO 2 into valuable chemicals with high selectivities, often above the limitation imposed by the classical Anderson-Schulz-Flory distribution (ASF). 9,10 In these bifunctional systems CO 2 conversion can proceed through two different routes depending on the first catalytic component: i) the transformation of CO 2 into methanol (MeOH) over a methanol synthesis catalyst 11 followed by a classical methanol to hydrocarbons (MTH) mechanism on the zeolite component 12 or, ii) the transformation of CO 2 into hydrocarbons via Fischer-Tropsch (FTS) over Fe based catalyst 13 followed by hydrocarbon oligomerization, cracking, isomerization and/or aromatization on the zeolite.…”

Engineering Metal–Organic Frameworks for the Electrochemical Reduction of CO2: A Minireview

“…All of these approaches have their own economic advantages under certain conditions, and they may all contribute to cutting the concentration of atmospheric CO 2 . For example, thermocatalysis would already be economically competitive if “green” hydrogen (e.g., generated from water splitting by using renewable energy) were readily available on a mass scale . On the other hand, photocatalysis is more favorable in remote locations with strong solar irradiation.…”