No abstract

Controlling the catalytic reduction of CO2 by H2 to produce CO, methanol or hydrocarbons requires stabilization of key reaction intermediates.

Rising atmospheric CO2 is expected to have negative effects on the global environment from its role in climate change and ocean acidification. Utilizing CO2 as a feedstock to make valuable chemicals is potentially more desirable than sequestration. A substantial reduction of CO2 levels requires a large-scale CO2 catalytic conversion process, which in turn requires the discovery of low-cost catalysts. Results from the current study demonstrate the feasibility of using the non-precious metal material molybdenum carbide (Mo2C) as an active and selective catalyst for CO2 conversion by H2.

The utilization of CO2 as a carbon source for synthesis of value-added chemicals and fuels, particularly light olefins, is one of the most attractive routes to convert CO2 as part of a large-scale process. Designing active, selective, and stable catalysts for olefin production is challenging because of the difficulty characterizing structure–property relationships for the highly complex CO2 hydrogenation reaction network. To understand the challenges and opportunities in converting CO2 directly to olefins over a single tandem catalyst, this Perspective reviews the following three routes: (1) direct hydrogenation of CO2 to olefins over promoted catalysts; (2) methanol synthesis followed by methanol-to-olefins (MeOH-mediated route); (3) CO production via the reverse-water–gas-shift reaction, followed by Fischer–Tropsch synthesis (CO-mediated route). Future research directions are proposed on the critical research areas of elucidating reaction mechanisms by combining in situ characterization techniques with density functional theory calculations, identifying structure–property relationships for the zeolite support, strategizing methods to increase catalyst lifetime, and developing advanced synthesis techniques for depositing a metal-based active phase within a zeolite for highly active, selective, and stable tandem catalysts.

Catalytic reduction of CO2 requires active, selective and low-cost catalysts. Results of this study show that transition metal carbides are a class of promising catalysts and their activity is correlated with oxygen binding energy and reducibility as shown by DFT calculations and in situ measurements.