In this paper, hierarchically porous MgMn.sub.2O.sub.4 microspheres, which assembled with average size of about 30 nm nanosheets, have been synthesized by a facile solvothermal process followed by ...calcination method. The electrocatalytic properties of the products towords oxygen reduction reaction (ORR) are further investigated. Benefitting from its unique structural characteristics, the hierarchically porous MgMn.sub.2O.sub.4 microspheres exhibit more positive onset potential and enhanced current density than the MgMn.sub.2O.sub.4 blocks and irregular sheets, and their ORR catalytic performance is better than the pure manganese oxide (Mn.sub.2O.sub.3) which is prepared through the same method. In addition, the MgMn.sub.2O.sub.4 microspheres own superior durability and methanol tolerance than that of Pt/C catalysts in spite of slight negative onset potential, which can be a promising non-noble metal ORR catalyst. Graphical LSV curves measured at 1600 rpm in O.sub.2-saturated 0.1 M KOH electrolyte with a scan rate of 5 mV s.sup.-1. And the inset image is SEM and TEM with different magnification of hierarchically porous MgMn2O4 microspheres.
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•Industrial-scale MeOH−CCU plant comparable with fossil production units.•The raw material consumption of the plant is lower than previously reported ones.•Optimisation of economic ...parameters could provide costs close to fossil methanol.•Cost of H2 and the annual output of the plant impacts the economic feasibility the most.
Global anthropogenic CO2 emissions are expected to peak to 40 Gt in 2020. If these emissions are not mitigated climate change and global warming will further aggregate. Meanwhile, demand for products and fuels produced from fossil raw materials are increasing. CO2, however, can be considered as feedstock for certain materials and processes. If CO2 is catalytically synthesised with H2 it can form a variety of hydrocarbons, such as methane, methanol (MeOH), higher alcohols, and liquid fuels. In this paper, a simulation model of a MeOH plant using CO2 and H2 as feedstock was developed in Aspen Plus™. This is the first plant studied at an industrial-scale comparable with fossil MeOH plant units. The plant produces 5 kt chemical-grade MeOH daily that can be used as raw material for the chemical industry or as a fuel. The kinetic model, considering both CO and CO2 as the source of carbon, accomplished high overall CO2 conversion rate and close to stoichiometric raw material utilisation. Under the current market conditions, the MeOH plant is not feasible even at this scale. The most significant cost parameter making the plant non-viable is attributed to the high cost of H2 produced by water electrolysis. A series of sensitivity analyses revealed that co-selling of O2 by-product from the electrolyser and lowering the H2 cost price have a significant factor in achieving a more competitive levelised cost of MeOH. These economic results are analysed in-depth with previous studies to reveal the effect of different economic assumptions.
A new approach for the alpha-arylation of acetic acid through Pd-catalyzed silver-mediated direct CH arylation of acetic acid with aryl iodides was developed. This protocol provided a straightforward ...method for the synthesis of a diverse set of alpha-phenylacetic acids. PUBLICATION ABSTRACT
The Cu/CeO.sub.2-nanopolyhedrals and pure Cu/CeO.sub.2-nanorods with different sizes were synthesized for CO.sub.2 hydrogenation to methanol. With increasing the percentage composition of CeO.sub.2 ...nanorods, the surface concentrations of Cu.sup.+, Ce.sup.3+ and oxygen vacancies were gradually enhanced. However, the amount of surface Cu.sup.+ species and oxygen vacancies would be decreased instead if the size of pure CeO.sub.2 nanorods was too large. The variation tendency of catalytic performance for CO.sub.2 hydrogenation to methanol was well consistent with that of Cu.sup.+ species and oxygen vacancies. Cu/CeO.sub.2 nanorods with small size exhibited the strongest interaction in Cu-CeO.sub.2 interface and the highest methanol production activity among all Cu/CeO.sub.2 nano-catalysts. The small size of CeO.sub.2-nanorods obtained at NaOH concentration of 10 mol/L, hydrothermal temperature of 80 °C and hydrothermal time of 24 h showed the best catalytic performance (X.sub.CO2 = 5.8%, S.sub.CH3OH = 92.0%, Y.sub.CH3OH = 5.3%) at 280 °C and 3 MPa. The stronger interaction accelerated the charge transfer between CuO.sub.x species and CeO.sub.2 nanorods, which produced the larger amount of surface Cu.sup.+ species and oxygen vacancies. The synergistic effect between reduced Cu species and oxygen vacancies improved methanol selectivity and was responsible for CO.sub.2 hydrogenation to methanol.
Natural photosynthesis is an effective route for the clean and sustainable conversion of CO2 into high‐energy chemicals. Inspired by the natural process, a tandem photoelectrochemical (PEC) cell with ...an integrated enzyme‐cascade (TPIEC) system was designed, which transfers photogenerated electrons to a multienzyme cascade for the biocatalyzed reduction of CO2 to methanol. A hematite photoanode and a bismuth ferrite photocathode were applied to fabricate the iron oxide based tandem PEC cell for visible‐light‐assisted regeneration of the nicotinamide cofactor (NADH). The cell utilized water as an electron donor and spontaneously regenerated NADH. To complete the TPIEC system, a superior three‐dehydrogenase cascade system was employed in the cathodic part of the PEC cell. Under applied bias, the TPIEC system achieved a high methanol conversion output of 220 μm h−1, 1280 μmol g−1 h−1 using readily available solar energy and water.
In synergy: A tandem photoelectrochemical (PEC) cell with an integrated enzyme cascade has been developed to transfer photogenerated electrons to a multienzyme cascade for the biocatalyzed reduction of CO2 to methanol in high yield. The approach makes use of water as an electron donor, a hematite photoanode and a bismuth ferrite photocathode for the regeneration of NADH with visible light, as well as a three‐dehydrogenase cascade system.
Since the early 2010s, China has been accelerating methanol vehicle development to secure energy supply and reduce environmental pollution. Although completed pilot projects have demonstrated the ...economic and technological maturity of methanol vehicles, their overall emissions are still high, as methanol is predominantly produced from coal in China. To combat this, two green methanol routes (CO2-to-methanol and biomass-to-methanol) have been proposed as vehicle fuels. Before further deployment, comprehensively comparing green methanol vehicles with other vehicles is crucial; therefore, based on life-cycle assessments and cost analyses, this study compared green methanol vehicles with coal-to-methanol, conventional gasoline, and electric vehicles considering energy-focused, environmental, and economic perspectives. Combined with these results, we developed a comprehensive evaluation model to prioritize green methanol vehicles among the different vehicles in China. The evaluation results show that biomethanol vehicle ranks first; the potential of CO2-to-methanol vehicle is limited because of its high fuel cost and high energy consumption: 2.6 and 13.9 times of biomethanol, respectively. Based on the designed scenarios, the government should develop a dynamic policy scheme consisting of scaling up the deployment of biomethanol vehicles according to local conditions and developing CO2-to-methanol vehicles if fuel technology advances considerably after carbon neutrality.
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•Assessed green methanol vehicles' life-cycle energy consumption, emission, cost.•A multi-criteria model was developed to rank green methanol vehicles in China.•M100-Bio-V ranks first; M100-CO2-V ranks the lowest due to its high fuel cost.•The energy consumption of CO2-to-methanol is 13.9 times of biomethanol.•Five policy implications for further deploying methanol vehicles were provided.
Significance With the recent discoveries of large reserves of natural gas, the efficient utilization of one-carbon compounds for chemical synthesis would reduce the raw material cost for the ...petroleum-based chemical industry. Methanol is produced industrially from methane and is a feedstock chemical for the synthesis of higher carbon compounds. However, current chemical synthesis of higher carbon compounds from methanol requires high temperature and pressure. Natural biological pathways for methanol utilization are carbon and ATP inefficient. Here we constructed a synthetic biocatalytic pathway that allows the efficient conversion of methanol to higher-chain alcohols or other higher carbon compounds without carbon loss or ATP expenditure. The high carbon efficiency and favorable operating conditions are attractive for industrial applications.
Methanol is an important intermediate in the utilization of natural gas for synthesizing other feedstock chemicals. Typically, chemical approaches for building C–C bonds from methanol require high temperature and pressure. Biological conversion of methanol to longer carbon chain compounds is feasible; however, the natural biological pathways for methanol utilization involve carbon dioxide loss or ATP expenditure. Here we demonstrated a biocatalytic pathway, termed the methanol condensation cycle (MCC), by combining the nonoxidative glycolysis with the ribulose monophosphate pathway to convert methanol to higher-chain alcohols or other acetyl-CoA derivatives using enzymatic reactions in a carbon-conserved and ATP-independent system. We investigated the robustness of MCC and identified operational regions. We confirmed that the pathway forms a catalytic cycle through ¹³C-carbon labeling. With a cell-free system, we demonstrated the conversion of methanol to ethanol or n -butanol. The high carbon efficiency and low operating temperature are attractive for transforming natural gas-derived methanol to longer-chain liquid fuels and other chemical derivatives.
Correction: Continuous reactor for renewable methanol Tountas, Athanasios A; Ozin, Geoffrey A; Sain, Mohini M
Green chemistry : an international journal and green chemistry resource : GC,
12/2020, Volume:
22, Issue:
23
Journal Article
Peer reviewed
Open access
Correction for 'Continuous reactor for renewable methanol' by Athanasios A. Tountas
et al.
,
Green Chem.
, 2020, DOI:
10.1039/d0gc03115a
.
Hydrogen is the alternative renewable energy source for addressing the energy crisis, global warming, and climate change. Hydrogen is mostly obtained in the industrial process by steam reforming of ...natural gas. In the present work, CuCrOsub.2 particles were attached to the surfaces of electrospun CeOsub.2 nanofibers to form CeOsub.2-CuCrOsub.2 nanofibers. However, the CuCrOsub.2 particles did not readily adhere to the surfaces of the CeOsub.2 nanofibers, so a trace amount of SiOsub.2 was added to the surfaces to make them hydrophilic. After the SiOsub.2 modification, the CeOsub.2 nanofibers were immersed in Cu-Cr-O precursor and annealed in a vacuum atmosphere to form CeOsub.2-CuCrOsub.2 nanofibers. The CuCrOsub.2, CeOsub.2, and CeOsub.2-CuCrOsub.2 nanofibers were examined by X-ray diffraction analysis, transmission electron microscopy, field emission scanning electron microscopy, scanning transmission electron microscope, thermogravimetric analysis, and Brunauer-Emmett-Teller studies (BET). The BET surface area of the CeOsub.2-CuCrOsub.2 nanofibers was 15.06 msup.2/g. The CeOsub.2-CuCrOsub.2 nanofibers exhibited hydrogen generation rates of up to 1335.16 mL minsup.−1 g-catsup.−1 at 773 K. Furthermore, the CeOsub.2-CuCrOsub.2 nanofibers produced more hydrogen at lower temperatures. The hydrogen generation performance of these CeOsub.2-CuCrOsub.2 nanofibers could be of great importance in industry and have an economic impact.
•The future market most likely requires both large and small scale methanol plants.•Catalysts with better low temperature activity or sulfur resistance are desirable.•Recent advances in catalyst ...synthesis and composition are remarkable and promising.•Models of the active site(s), Cu-ZnO synergy and reaction mechanism begin to emerge.
This article provides a brief overview of methanol synthesis with emphasis on commercial catalysts and some of the relevant literature on this subject. Firstly, industrial production of this very applicable molecule, as well as a summary of manufacturing trends and challenges are presented. Secondly, requirements for methanol synthesis catalysts and recent advances in catalyst synthesis and compositions are examined and finally, reaction mechanism and the Cu-ZnO synergy in industrial methanol synthesis catalysts are discussed together with literature tendencies and possible future developments in this classic, but lively research area.
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