Tandem Catalysis for CO2 Hydrogenation to C2–C4 Hydrocarbons

In order to explore co-production alternatives, a once-through process for CO2 hydrogenation to chemicals and liquid fuels was investigated experimentally. In this approach, two different catalysts were considered; the first was a Cu-based catalyst that hydrogenates CO2 to methanol and CO and the second a Fisher–Tropsch (FT) Co-based catalyst. The two catalysts were loaded into different reactors and were initially operated separately. The experimental results show that: (1) the Cu catalyst was very active in both the methanol synthesis and reverse-water gas shift (R-WGS) reactions and these two reactions were restricted by thermodynamic equilibrium; this was also supported by an Aspen plus simulation of an (equilibrium) Gibbs reactor. The Aspen simulation results also indicated that the reactor can be operated adiabatically under certain conditions, given that the methanol reaction is exothermic and R-WGS is endothermic. (2) the FT catalyst produced mainly CH4 and short chain saturated hydrocarbons when the feed was CO2/H2. When the two reactors were coupled in series and the presence of CO in the tail gas from the first reactor (loaded with Cu catalyst) significantly improves the FT product selectivity toward higher carbon hydrocarbons in the second reactor compared to the standalone FT reactor with only CO2/H2 in the feed.

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Plastic waste to fuels by hydrocracking at mild conditions

Science Advances ◽

10.1126/sciadv.abf8283 ◽

2021 ◽

Vol 7 (17) ◽

pp. eabf8283

Author(s):

Sibao Liu ◽

Pavel A. Kots ◽

Brandon C. Vance ◽

Andrew Danielson ◽

Dionisios G. Vlachos

Keyword(s):

Direct Method ◽

Acid Sites ◽

Liquid Fuels ◽

High Yield ◽

Tandem Catalysis ◽

Hy Zeolite ◽

Environmental Threat ◽

Single Use ◽

Initial Activation ◽

A Direct Method

Single-use plastics impose an enormous environmental threat, but their recycling, especially of polyolefins, has been proven challenging. We report a direct method to selectively convert polyolefins to branched, liquid fuels including diesel, jet, and gasoline-range hydrocarbons, with high yield up to 85% over Pt/WO3/ZrO2 and HY zeolite in hydrogen at temperatures as low as 225°C. The process proceeds via tandem catalysis with initial activation of the polymer primarily over Pt, with subsequent cracking over the acid sites of WO3/ZrO2 and HY zeolite, isomerization over WO3/ZrO2 sites, and hydrogenation of olefin intermediates over Pt. The process can be tuned to convert different common plastic wastes, including low- and high-density polyethylene, polypropylene, polystyrene, everyday polyethylene bottles and bags, and composite plastics to desirable fuels and light lubricants.

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Boron insertion into alkyl ether bonds via zinc/nickel tandem catalysis

Science ◽

10.1126/science.abg5526 ◽

2021 ◽

Vol 372 (6538) ◽

pp. 175-182

Author(s):

Hairong Lyu ◽

Ilia Kevlishvili ◽

Xuan Yu ◽

Peng Liu ◽

Guangbin Dong

Keyword(s):

Nickel Catalyst ◽

Bioactive Compounds ◽

Cyclic Ethers ◽

Alkyl Ether ◽

Tandem Catalysis ◽

Mechanistic Studies ◽

Alkyl Ethers ◽

Nitrogen Substitution ◽

Zinc Nickel

Mild methods to cleave the carbon-oxygen (C−O) bond in alkyl ethers could simplify chemical syntheses through the elaboration of these robust, readily available precursors. Here we report that dibromoboranes react with alkyl ethers in the presence of a nickel catalyst and zinc reductant to insert boron into the C−O bond. Subsequent reactivity can effect oxygen-to-nitrogen substitution or one-carbon homologation of cyclic ethers and more broadly streamline preparation of bioactive compounds. Mechanistic studies reveal a cleavage-then-rebound pathway via zinc/nickel tandem catalysis.

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Facet effect of In2O3 for methanol synthesis by CO2 hydrogenation: a mechanistic and kinetic study

Surfaces and Interfaces ◽

10.1016/j.surfin.2021.101244 ◽

2021 ◽

pp. 101244

Author(s):

Wenyi Wang ◽

Yifei Chen ◽

Minhua Zhang

Keyword(s):

Kinetic Study ◽

Methanol Synthesis ◽

Co2 Hydrogenation

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Understanding the structure-performance relationship of cubic In2O3 catalysts for CO2 hydrogenation

Journal of CO2 Utilization ◽

10.1016/j.jcou.2021.101543 ◽

2021 ◽

Vol 49 ◽

pp. 101543

Author(s):

Bin Qin ◽

Zhimin Zhou ◽

Shenggang Li ◽

Peng Gao

Keyword(s):

Co2 Hydrogenation ◽

Relationship Of

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Synergistic Effect of Alkali Na and K Promoter on Fe-Co-Cu-Al Catalysts for CO2 Hydrogenation to Light Hydrocarbons

Catalysts ◽

10.3390/catal11060735 ◽

2021 ◽

Vol 11 (6) ◽

pp. 735

Author(s):

Yuhao Zheng ◽

Chenghua Xu ◽

Xia Zhang ◽

Qiong Wu ◽

Jie Liu

Keyword(s):

Synergistic Effect ◽

Active Sites ◽

Intermediate Formation ◽

Active Phase ◽

Dissociative Adsorption ◽

Co2 Hydrogenation ◽

Chain Growth ◽

Co2 Conversion ◽

Light Hydrocarbons ◽

Active Centers

Alkali metal K- and/or Na-promoted FeCoCuAl catalysts were synthesized by precipitation and impregnation, and their physicochemical and catalytic performance for CO2 hydrogenation to light hydrocarbons was also investigated in the present work. The results indicate that Na and/or K introduction leads to the formation of active phase metallic Fe and Fe-Co crystals in the order Na < K < K-Na. The simultaneous introduction of Na and K causes a synergistic effect on increasing the basicity and electron-rich property, promoting the formation of active sites Fe@Cu and Fe-Co@Cu with Cu0 as a crystal core. These effects are advantageous to H2 dissociative adsorption and CO2 activation, giving a high CO2 conversion with hydrogenation. Moreover, electron-rich Fe@Cu (110) and Fe-Co@Cu (200) provide active centers for further H2 dissociative adsorption and O-C-Fe intermediate formation after adsorption of CO produced by RWGS. It is beneficial for carbon chain growth in C2+ hydrocarbons, including olefins and alkanes. FeCoCuAl simultaneously modified by K-Na exhibits the highest CO2 conversion and C2+ selectivity of 52.87 mol% and 89.70 mol%, respectively.

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