Owing to the increasing emissions of carbon dioxide (CO2), human life and the ecological environment have been affected by global warming and climate changes. To mitigate the concentration of CO2 in the atmosphere various strategies have been implemented such as separation, storage, and utilization of CO2. Although it has been explored for many years, hydrogenation reaction, an important representative among chemical conversions of CO2, offers challenging opportunities for sustainable development in energy and the environment. Indeed, the hydrogenation of CO2 not only reduces the increasing CO2 buildup but also produces fuels and chemicals. In this critical review we discuss recent developments in this area, with emphases on catalytic reactivity, reactor innovation, and reaction mechanism. We also provide an overview regarding the challenges and opportunities for future research in the field (319 references).

Recent advances in catalytic hydrogenation of carbon dioxide

Catalysis for the valorization of exhaust carbon: from CO2 to chemicals, materials, and fuels. technological use of CO2.

Two major energy-related problems confront the world in the
next 50 years. First, increased worldwide competition for
gradually depleting fossil fuel reserves (derived from past
photosynthesis) will lead to higher costs, both monetarily and politically. Second, atmospheric CO_2 levels are at their highest recorded level since records began. Further increases are predicted to produce large and uncontrollable impacts on the world climate. These projected impacts extend beyond climate to ocean acidification, because the ocean is a major sink for atmospheric CO2.1 Providing a future energy supply that is secure and CO_2-neutral will require switching to nonfossil energy sources such as wind, solar, nuclear, and geothermal energy and developing methods for transforming the energy produced by these new sources into forms that can be stored, transported, and used upon demand.

Frontiers, Opportunities, and Challenges in Biochemical and Chemical Catalysis of CO2 Fixation

A plethora of methods have been developed over the years so that carbon dioxide can be used as a reactant in organic synthesis. Given the abundance of this compound, its utilization in synthetic chemistry, particularly on an industrial scale, is still at a rather low level. In the last 35 years, considerable research has been performed to find catalytic routes to transform CO(2) into carboxylic acids, esters, lactones, and polymers in an economic way. This Review presents an overview of the available homogeneous catalytic routes that use carbon dioxide as a C(1) carbon source for the synthesis of industrial products as well as fine chemicals.

Transformation of Carbon Dioxide with Homogeneous Transition-Metal Catalysts: A Molecular Solution to a Global Challenge?

Photoand Electrochemical CO2 Reduction Wan-Hui Wang,*,† Yuichiro Himeda,*,‡,§ James T. Muckerman, Gerald F. Manbeck, and Etsuko Fujita* †School of Petroleum and Chemical Engineering, Dalian University of Technology, Panjin 124221, China ‡National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5-1, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan JST, ACT-C, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States

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CO2 Hydrogenation to Formate and Methanol as an Alternative to Photo- and Electrochemical CO2 Reduction

Catalytic hydrogenation of carbon dioxide in aqueous potassium hydroxide was performed using a newly synthesized isopropyl-substituted PNP-pincer iridium trihydride complex as a catalyst. Potassium formate was obtained with turnover numbers up to 3 500 000 and a turnover frequency of 150 000 h−1, both of which are the highest values reported to date.

Catalytic Hydrogenation of Carbon Dioxide Using Ir(III)-Pincer Complexes

Mechanistic Studies on the Reversible Hydrogenation of Carbon Dioxide Catalyzed by an Ir-PNP Complex

Copolymerizations of ethylene with polar monomers such as 5-hexene-1-yl acetate and allyl acetate are explored using nickel complexes bearing a class of anilinonaphthoquinone ligands. High tolerability of this complex toward polar comonomer is achieved by the installation of sterically bulky substituent on the aniline ligand. Moreover, the heterogenization of the nickel complexes using silica-supported modified methylaluminoxane enhances the copolymerization performances. The catalyst is highly active and thermally stabile to give semicrystalline ester-functionalized high molecular weight polyethylenes.

Highly Robust Nickel Catalysts Containing Anilinonaphthoquinone Ligand for Copolymerization of Ethylene and Polar Monomers

The Hall effect is investigated for eight superconducting $\text{Fe}({\text{Se}}_{0.5}{\text{Te}}_{0.5})$ thin films grown on MgO and ${\text{LaSrAlO}}_{4}$ substrates with different transition temperatures $({T}_{c})$. The normal Hall coefficients $({R}_{H})$ have positive values with magnitude of $1\ensuremath{\sim}1.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}\text{ }{\text{cm}}^{3}/\text{C}$ at room temperature for the all samples. With decreasing temperature, we find two characteristic types of behavior in ${R}_{H}(T)$ depending on ${T}_{c}$. For thin films with lower ${T}_{c}$ (typically ${T}_{c}l5\text{ }\text{K}$), ${R}_{H}$ start decreasing approximately below $T=250\text{ }\text{K}$ toward a negative side, some of which shows sign reversal at $T=50\ensuremath{\sim}60\text{ }\text{K}$, but turns positive toward $T=0\text{ }\text{K}$. On the other hand, for the films with higher ${T}_{c}$ (typically ${T}_{c}g9\text{ }\text{K}$), ${R}_{H}$ leaves almost unchanged down to $T\ensuremath{\approx}100\text{ }\text{K}$, and then starts decreasing toward a negative side. Around the temperatures when ${R}_{H}$ changes its sign from positive to negative, obvious nonlinearity is observed in the field-dependence of Hall resistance as to keep the low-field ${R}_{H}$ positive while the high-field ${R}_{H}$ negative. Thus, the electronic state just above ${T}_{c}$ is characterized by ${n}_{e}$ (electron density) $g{n}_{h}$ (hole density) with keeping ${\ensuremath{\mu}}_{e}l{\ensuremath{\mu}}_{h}$. These results suggest the dominance of electron density to the hole density is an essential factor for the occurrence of superconductivity in Fe-chalcogenide superconductors.

Hall effect in superconducting Fe ( Se 0.5 Te 0.5 ) thin films

FeSe0.5Te0.5 thin films with a PbO-type structure are successfully grown on MgO(100) and LaSrAlO4(001) substrates from FeSe0.5Te0.5 or FeSe0.5Te0.75 polycrystalline targets by pulsed laser deposition. The film deposited on the MgO substrate (film thickness: ~55 nm) shows superconductivity at 10.6 K (onset) and 9.2 K (zero resistivity). On the other hand, the film deposited on the LaSrAlO4 substrate (film thickness: ~250 nm) exhibits superconductivity at 5.4 K (onset) and 2.7 K (zero resistivity). This suggests the strong effect of substrate materials and/or the c-axis length on the superconducting properties of FeSe0.5Te0.5 thin films.

http://iopscience.iop.org/article/10.1143/JJAP.49.023101/pdf

Ryo Tanaka

Papers

Catalytic Hydrogenation of Carbon Dioxide Using Ir(III)-Pincer Complexes

Mechanistic Studies on the Reversible Hydrogenation of Carbon Dioxide Catalyzed by an Ir-PNP Complex

Highly Robust Nickel Catalysts Containing Anilinonaphthoquinone Ligand for Copolymerization of Ethylene and Polar Monomers

Hall effect in superconducting Fe ( Se 0.5 Te 0.5 ) thin films

Superconductivity of FeSe0.5Te0.5 Thin Films Grown by Pulsed Laser Deposition