A short review of recent advances in CO2 hydrogenation to hydrocarbons over heterogeneous catalysts

Abstract

CO₂ hydrogenation to hydrocarbons is a promising way of making waste to wealth and energy storage, which also solves the environmental and energy issues caused by CO₂ emissions. Much efforts and research are aimed at the conversion of CO₂ via hydrogenation to various value-added hydrocarbons, such as CH₄, lower olefins, gasoline, or long-chain hydrocarbons catalyzed by different catalysts with various mechanisms. This review provides an overview of advances in CO₂ hydrogenation to hydrocarbons that have been achieved recently in terms of catalyst design, catalytic performance and reaction mechanism from both experiments and density functional theory calculations. In addition, the factors influencing the performance of catalysts and the first C-C coupling mechanism through different routes are also revealed. The fundamental factor for product selectivity is the surface H/C ratio adjusted by active metals, supports and promoters. Furthermore, the technical and application challenges of CO₂ conversion into useful fuels/chemicals are also summarized. To meet these challenges, future research directions are proposed in this review.

Fig. 1. Conversion of CO₂ to chemicals and fuels through hydrogenation.

Fig. 2. Schematic illustration of CO₂-based sustainable production of chemicals and fuels.

Fig. 3. Equilibrium conversion of CO₂ in methanation at different temperatures (plotted using the data from the literature).

Fig. 4. STEM-EDS maps and corresponding TEM images of (a) calcined catalyst precursors Co₃O₄/ZrO₂ and (b) reduced catalyst Co/ZrO₂. Reprinted with permission from ref. 62. Copyright 2017 Elsevier.

Fig. 5. Schematic illustration of the shape evolution of RuO₂/TiO₂ catalysts: after RuO₂ nanoparticle deposition, after thermal annealing at 450 °C, and after reduction and methanation. Red indicates RuO₂, pink indicates thin RuO₂ layer, white indicates Ru depleted area, and black indicates metallic Ru. Reprinted with permission from ref. 67. Copyright 2013 RSC.

Fig. 6. (a) TOFs of CO and CH₄ formation at steady state at 300 °C over Ru/Al₂O₃ catalysts as a function of Ru loading. (b) CO selectivity as a function of Ru loading at 300 °C. Reprinted with permission from ref. 47. Copyright 2013 ACS.

Fig. 7. Potential energy diagram of three mechanisms of CO₂ methanation. Reprinted with permission from ref. 92. Copyright 2015 Elsevier.

Fig. 8. Mechanism of CO₂ methanation on ZrO₂-supported Ni catalysts. Reprinted with permission from ref. 99. Copyright 2017 Elsevier.

Fig. 9. Reaction scheme for CO₂ hydrogenation to gasoline-range hydrocarbons through modified FTS route. Reprinted with permission from ref. 105. Copyright 2017 Nature.

Fig. 10. Schematic diagram of CO₂ hydrogenation on CeO₂–Pt@mSiO₂–Co core–shell catalysts. Reprinted with permission from ref. 118. Copyright 2017 ACS.

Fig. 11. Reaction steps of CO₂ hydrogenation over composite catalyst (favorable paths are shown in bold lines). Reprinted with permission from ref. 125. Copyright 2015 Elsevier.

Fig. 12. Reaction networks examined to identify energetically favorable C1 species from CO₂ hydrogenation on (a) Fe(100) and (b) Cu–Fe(100) surface at 4/9 ML Cu coverage. Activation barriers are given in eV (the networks connected with red arrows represent the preferred path for CO₂ conversion to CH*). Reprinted with permission from ref. 109. Copyright 2017 ACS.

Fig. 13. Proposed reduction pathways for the production of C₂H₄ in the reduction mechanism of CO dimer on Cu(100). Reprinted with permission from ref. 150. Copyright 2015 RSC.