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Showing papers on "Methanol published in 2014"


Journal ArticleDOI
TL;DR: A richer surface chemistry for transition metals than previously known is revealed and new insights to guide the development of improved CO2 conversion catalysts are provided.
Abstract: Fuels and industrial chemicals that are conventionally derived from fossil resources could potentially be produced in a renewable, sustainable manner by an electrochemical process that operates at room temperature and atmospheric pressure, using only water, CO2, and electricity as inputs. To enable this technology, improved catalysts must be developed. Herein, we report trends in the electrocatalytic conversion of CO2 on a broad group of seven transition metal surfaces: Au, Ag, Zn, Cu, Ni, Pt, and Fe. Contrary to conventional knowledge in the field, all metals studied are capable of producing methane or methanol. We quantify reaction rates for these two products and describe catalyst activity and selectivity in the framework of CO binding energies for the different metals. While selectivity toward methane or methanol is low for most of these metals, the fact that they are all capable of producing these products, even at a low rate, is important new knowledge. This study reveals a richer surface chemistry ...

1,136 citations


Journal ArticleDOI
TL;DR: This work synthesized and tested a series of catalysts and found that Ni5Ga3 is particularly active and selective, and suggests that this is a first step towards the development of small-scale low-pressure devices for CO2 reduction to methanol.
Abstract: The use of methanol as a fuel and chemical feedstock could become very important in the development of a more sustainable society if methanol could be efficiently obtained from the direct reduction of CO2 using solar-generated hydrogen. If hydrogen production is to be decentralized, small-scale CO2 reduction devices are required that operate at low pressures. Here, we report the discovery of a Ni-Ga catalyst that reduces CO2 to methanol at ambient pressure. The catalyst was identified through a descriptor-based analysis of the process and the use of computational methods to identify Ni-Ga intermetallic compounds as stable candidates with good activity. We synthesized and tested a series of catalysts and found that Ni5Ga3 is particularly active and selective. Comparison with conventional Cu/ZnO/Al2O3 catalysts revealed the same or better methanol synthesis activity, as well as considerably lower production of CO. We suggest that this is a first step towards the development of small-scale low-pressure devices for CO2 reduction to methanol.

786 citations


Journal ArticleDOI
TL;DR: In this article, a new strategy for in situ synthesis of N-doped porous carbons as metal-free electrocatalysts for oxygen reduction reaction (ORR) in fuel cells was proposed.
Abstract: We have successfully prepared nanoporous Carbon-L and -S materials by using ZIF-7 as a precursor and glucose as an additional carbon source. Results indicate that Carbon-L and -S show an appropriate nitrogen content, high surface area, robust pore structure and excellent graphitization degree. The addition of an environmentally friendly carbon source – glucose – not only improves the graphitization degree of samples, but also plays a key role in removing residual Zn metal and zinc compound impurities, which makes the resulting materials metal-free in situ nitrogen-doped porous carbons. By further investigating the electrocatalytic performance of these nitrogen-doped porous carbons for oxygen reduction reaction (ORR), we find that Carbon-L, as a metal-free electrocatalyst, shows excellent electrocatalytic activity (the onset and half-wave potentials are 0.86 and 0.70 V vs. RHE, respectively) and nearly four electron selectivity (the electron transfer number is 3.68 at 0.3 V), which is close to commercial 20% Pt/C. Moreover, when methanol was added, the Pt/C catalyst would be poisoned while the Carbon-L and -S would be unaffected. By exploring the current-time chronoamperometric response in 25 000 s, we found that the duration stability of Carbon-L is much better than the commercial 20% Pt/C. Thus, both Carbon-L and -S exhibit excellent ability to avoid methanol crossover effects, and long-term operation stability superior to the Pt/C catalyst. This work provides a new strategy for in situ synthesis of N-doped porous carbons as metal-free electrocatalysts for ORR in fuel cells.

691 citations


Journal ArticleDOI
TL;DR: In this paper, a novel type of nitrogen-doped nanoporous carbon nanosheets derived from a conveniently available and accessible plant, Typha orientalis, was reported.
Abstract: Catalysts for oxygen reduction reaction (ORR) are crucial in fuel cells. Developing metal-free catalyst with high activity at low-cost and high-volume production remains a great challenge. Here, we report a novel type of nitrogen-doped nanoporous carbon nanosheets derived from a conveniently available and accessible plant, Typha orientalis. The nanosheets have high surface area (the highest surface area can be 898 m2 g−1), abundant micropores and high content of nitrogen (highest content of 9.1 at.%). The typical product exhibits an unexpected, surprisingly high ORR activity. In alkaline media, it exhibits similar catalytic activity but superior tolerance to methanol as compared to commercial 20% Pt/C. In acidic media as well, it shows excellent catalytic ability, stability and tolerance to methanol. This low-cost, simple and readily scalable approach provides a straightforward route to synthesize excellent electrocatalysts directly from biomass, which may find broad applications in the fields of supercapacitors, sensors, and gas uptake.

501 citations


Journal ArticleDOI
TL;DR: In this article, a review illustrates the earlier state-of-the-art from an experimental point of view about hydrogen production from methanol reforming performed in both conventional and membrane reactors.
Abstract: In the recent years, hydrogen has gained a considerable interest as an energy carrier useful for various applications and, particularly, for polymer electrolyte membrane fuel cells (PEMFCs) supply. Nevertheless, PEMFCs require high purity hydrogen as a feeding fuel, which shows some limitations regarding storage and transportation. Therefore, to overcome these problems, the in situ hydrogen generation has made attractive both alcohols and hydrocarbons steam reforming reaction. Among other fuels, methanol is an interesting hydrogen source because it is liquid at ambient conditions, possesses relatively high H/C ratio, low reforming temperature (200–300 °C) and it is also producible from biomass. Meanwhile, there is a comprehensive literature about inorganic membrane reactors utilization for hydrogen generation via methanol steam reforming reaction. This review illustrates the earlier state of the art from an experimental point of view about hydrogen production from methanol reforming performed in both conventional and membrane reactors. Furthermore, a short overview about methanol reforming catalysts as well as a discussion on the impact of methanol steam reforming process via inorganic membrane reactors to produce hydrogen for PEMFCs supply is given.

355 citations


Journal ArticleDOI
TL;DR: The role of water solvation on CO2 reduction paths was explored by evaluating water-assisted surface hydrogenation and proton (H) shuttling with various solvation models as discussed by the authors.

340 citations


Journal ArticleDOI
TL;DR: In this article, a mesoporous nitrogen-doped carbon prepared from (1-methyl-1H-pyrrole-2-yl)methanol in the presence of a meso-SiO2 template (KIT-6) is presented.
Abstract: Electrochemical reduction of oxygen molecules can produce H2O2, which is an important chemical for a green and sustainable society; therefore, the development of catalysts for this reaction is necessary. We propose mesoporous nitrogen-doped carbon prepared from (1-methyl-1H-pyrrole-2-yl)methanol in the presence of a mesoporous SiO2 template (KIT-6). The nitrogen content of the resulting carbon can be controlled in the range of 0–10 at. % and all prepared samples have well-ordered mesopores with diameters of 3.4–4.0 nm. Electrochemical studies indicate the present materials have high catalytic activities with high selectivity toward H2O2 over 90%. Such high selectivity toward H2O2 is probably due to good mass transport in the catalyst layer, which is enhanced by the mesoporous structure.

320 citations


Journal ArticleDOI
TL;DR: One-step valorization of soda lignin in supercritical ethanol using a CuMgAlOx catalyst results in high monomer yield (23 wt%) without char formation and Phenolic hydroxyl groups were found to be the main actors in repolymerization and char formation.
Abstract: One-step valorization of soda lignin in supercritical ethanol using a CuMgAlOx catalyst results in high monomer yield (23 wt?%) without char formation. Aromatics are the main products. The catalyst combines excellent deoxygenation with low ring-hydrogenation activity. Almost half of the monomer fraction is free from oxygen. Elemental analysis of the THF-soluble lignin residue after 8 h reaction showed a 68?% reduction in O/C and 24?% increase in H/C atomic ratios as compared to the starting Protobind P1000 lignin. Prolonged reaction times enhanced lignin depolymerization and reduced the amount of repolymerized products. Phenolic hydroxyl groups were found to be the main actors in repolymerization and char formation. 2D HSQC NMR analysis evidenced that ethanol reacts by alkylation and esterification with lignin fragments. Alkylation was found to play an important role in suppressing repolymerization. Ethanol acts as a capping agent, stabilizing the highly reactive phenolic intermediates by O-alkylating the hydroxyl groups and by C-alkylating the aromatic rings. The use of ethanol is significantly more effective in producing monomers and avoiding char than the use of methanol. A possible reaction network of the reactions between the ethanol and lignin fragments is discussed.

300 citations


Journal ArticleDOI
TL;DR: In this paper, solvent-extracted lignin from candlenut (Aleurites moluccana) biomass was subjected to catalytic depolymerization in methanol with an added pressure of H2, using a porous metal oxide catalyst (PMO) derived from a Cu-doped hydrotalcite-like precursor.

231 citations


Journal ArticleDOI
TL;DR: Structural changes that are strongly dependent on the pretreatment method have now been observed for an industrial-type methanol synthesis catalyst and a combination of chemisorption, reaction, and spectroscopic techniques provides a consistent picture of surface alloying between copper and zinc.
Abstract: Methanol has recently attracted renewed interest because of its potential importance as a solar fuel.1 Methanol is also an important bulk chemical that is most efficiently formed over the industrial Cu/ZnO/Al2O3 catalyst. The identity of the active site and, in particular, the role of ZnO as a promoter for this type of catalyst is still under intense debate.2 Structural changes that are strongly dependent on the pretreatment method have now been observed for an industrial-type methanol synthesis catalyst. A combination of chemisorption, reaction, and spectroscopic techniques provides a consistent picture of surface alloying between copper and zinc. This analysis enables a reinterpretation of the methods that have been used for the determination of the Cu surface area and provides an opportunity to independently quantify the specific Cu and Zn areas. This method may also be applied to other systems where metal–support interactions are important, and this work generally addresses the role of the carrier and the nature of the interactions between carrier and metal in heterogeneous catalysts.

229 citations


Journal ArticleDOI
TL;DR: In this article, the Pt-Ni2P/C-30% catalyst was integrated into a direct methanol fuel cell; this fuel cell exhibits a maximum power density of 65 mW cm−2, more than twice of that of an analogous fuel cell using Pt/C as the anode catalyst.
Abstract: Pt is the state-of-the-art anode catalyst in direct methanol fuel cells. Here we report that Ni2P promotes the activity and stability of Pt in electrochemical methanol oxidation. Nanoparticles of Ni2P and Pt were co-deposited on a carbon support and their activity in electrochemical methanol oxidation was measured by cyclic voltammetry. Among all Pt–Ni2P/C catalysts, the sample with a 30 wt% loading of Ni2P exhibits the highest electrochemical surface area and activity. The activity of the Pt–Ni2P/C-30% catalyst is significantly higher than that of Pt/C, Ni-promoted Pt/C, and P-promoted Pt/C catalysts, revealed by cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. Accordingly to X-ray photoelectron spectroscopy, there is a partial electron transfer from Ni2P to Pt, which might be an origin of the enhanced catalytic activity of the Pt/Ni2P bimetallic catalyst. The Pt–Ni2P/C-30% was integrated into a direct methanol fuel cell; this fuel cell exhibits a maximum power density of 65 mW cm−2, more than twice of that of an analogous fuel cell using Pt/C as the anode catalyst. The Pt–Ni2P/C-30%-integrated direct methanol fuel cell has also the highest discharge stability among a series of fuel cells with different Pt-based anode catalysts.

Journal ArticleDOI
TL;DR: In this article, the underlying mechanisms of two distinct catalytic cycles operating during conversion of methanol to olefins (MTO) on HZSM-5 have been elucidated under industrially relevant conditions.

Journal ArticleDOI
TL;DR: In this paper, homogeneous catalytic hydrogenation of CO2 and its derivatives into methanol is highlighted in combination with mechanistic understanding on a molecular level, in order to understand the interaction of active catalytic species with CO2 or hydrogen.

Journal ArticleDOI
TL;DR: In this article, the authors reported an exceptionally productive process for the synthesis of methanol via continuous catalytic hydrogenation of CO2 under high pressure conditions (up to 360 bar) over co-precipitated Cu/ZnO/Al2O3 catalysts.

Journal ArticleDOI
Abstract: The effects of the most largely employed preparation methods (i.e . , coprecipitation with sodium bicarbonate, complexation with citric acid, gel-oxalate coprecipitation) on the structure and catalytic behaviour of Cu-Zn-Zr systems for methanol synthesis from hydrogenation of carbon dioxide have been studied. The characterization data of the dried, calcined and reduced catalysts showed that the physico-chemical properties can be controlled by varying composition and preparation method. The catalyst obtained by the gel-coprecipitation procedure showed the highest catalytic activity in the T R range 453–513 K, 3.0 MPa and 10,000 h −1 , due to a superior functionality in the CO 2 and H 2 activation. An adequate balance between metal and oxide surface sites, in correspondence of a well defined particle size, was proposed to be crucial to design active and selective catalysts for such reaction. The good performance of the gel-oxalate coprecipitated catalyst was confirmed by an endurance test (≈200 h), in which a constant and remarkable methanol space–time-yield value of 1200 g kg cat −1 h −1 at ≈10% CO 2 conversion was obtained ( T R , 513 K; P R , 3.0 MPa).

Journal ArticleDOI
TL;DR: The single Pt1 and Au1 atoms stabilized by lattice oxygen on ZnO{1010} surface for methanol steam reforming was reported in this paper, where density functional theory calculations reveal that the catalysis of the single precious metal atoms together with coordinated latticeoxy stems from its stronger binding toward the intermediates, lowering reaction barriers, changing on the reaction pathway, enhancing greatly the activity.
Abstract: The single Pt1 and Au1 atoms stabilized by lattice oxygen on ZnO{1010} surface for methanol steam reforming is reported. Density functional theory calculations reveal that the catalysis of the single precious metal atoms together with coordinated lattice oxygen stems from its stronger binding toward the intermediates, lowering reaction barriers, changing on the reaction pathway, enhancing greatly the activity. The measured turnover frequency of single Pt1 sites was more than 1000 times higher than the pristine ZnO. The results provide valuable insights for the catalysis of the atomically dispersed precious metals on oxide supports.

Journal ArticleDOI
TL;DR: The rhodium-catalyzed methylation of ketones has been accomplished using methanol as the methylating agent and the hydrogen-borrowing method, notable for the relatively low temperatures that are required and for the ability of the reaction system to form α-branched products with ease.
Abstract: The rhodium-catalyzed methylation of ketones has been accomplished using methanol as the methylating agent and the hydrogen-borrowing method. The sequence is notable for the relatively low temperatures that are required and for the ability of the reaction system to form α-branched products with ease. Doubly alkylated ketones can be prepared from methyl ketones and two different alcohols by using a sequential one-pot iridium- and rhodium-catalyzed process.

Journal ArticleDOI
TL;DR: In this article, the authors developed efficient and environmentally benign heterogeneous catalysts for biodiesel production by pre-impregnation method, and the prepared catalyst was tested for the transesterification process of soybean oil to produce biodiesel.

Journal ArticleDOI
TL;DR: An efficient system catalyzed by a Ru-PNN pincer complex was developed for reforming methanol to H2 and CO2 (absorbed by base) under relatively low temperature (around 100 °C), and good yields of H2 were obtained as discussed by the authors.
Abstract: An efficient system catalyzed by a Ru-PNN pincer complex was developed for reforming methanol to H2 and CO2 (absorbed by base) under relatively low temperature (around 100 °C), and good yields of H2 were obtained (∼80%). The catalyst solution can be reused without isolation and purification, with no decrease in catalytic activity being observed for a period of ∼1 month. Decomposition of formic acid, which is likely to be the last step of the methanol reforming reaction, was also investigated, and the formic acid adduct of the catalyst was fully characterized spectroscopically and by X-ray crystallography.

Journal ArticleDOI
TL;DR: This Account describes recent developments in an alternative approach for the synthesis of ethanol via synthetic gas that enables a more sustainable ethanol, methyl glycolate, and ethylene glycol synthesis in industry and greatly reduces the dependence on petroleum resources and the emission of the greenhouse gas.
Abstract: Ethanol is an attractive end product and a versatile feedstock because a widespread market exists for its commercial use as a fuel additive or a potential substitute for gasoline. Currently, ethanol is produced primarily by fermentation of biomass-derived sugars, particularly those containing six carbons, but coproducts 5-carbon sugars and lignin remain unusable. Another major process for commercial production of ethanol is hydration of ethylene over solid acidic catalysts, yet not sustainable considering the depletion of fossil fuels. Catalytic conversion of synthetic gas (CO + H2) could produce ethanol in large quantities. However, the direct catalytic conversion of synthetic gas to ethanol remains challenging, and no commercial process exists as of today although the research has been ongoing for the past 90 years, since such the process suffers from low yield and poor selectivity due to slow kinetics of the initial C-C bond formation and fast chain growth of the C2 intermediates. This Account describes recent developments in an alternative approach for the synthesis of ethanol via synthetic gas. This process is an integrated technology consisting of the coupling of CO with methanol to form dimethyl oxalate and the subsequent hydrogenation to yield ethanol. The byproduct of the second step (methanol) can be separated and used in circulation as the feedstock for the coupling step. The coupling reaction of carbon monoxide for producing dimethyl oxalate takes place under moderate reaction conditions with high selectivity (∼95%), which ideally leads to a self-closing, nonwaste, catalytic cycling process. This Account also summarizes the progress on the development of copper-based catalysts for the hydrogenation reaction with remarkable efficiencies and stability. The unique lamellar structure and the cooperative effect between surface Cu(0) and Cu(+) species are responsible for the activity of the catalyst with high yield of ethanol (∼91%). The understanding of nature of valence states of Cu could also guide the rational design of Cu-based catalysts for other similar reactions, particularly for hydrogenation catalytic systems. In addition, by regulating the reaction condition and the surface structure of the catalysts, the products in the hydrogenation steps, such as ethanol, methyl glycolate, and ethylene glycol, could be tuned efficiently. This synthetic approach enables a more sustainable ethanol, methyl glycolate, and ethylene glycol synthesis in industry and greatly reduces the dependence on petroleum resources and the emission of the greenhouse gas.

Journal ArticleDOI
01 Nov 2014-Fuel
TL;DR: In this paper, the effect of reaction temperature, catalyst concentration, algae biomass to methanol ratio (wt:vol), stirring intensity and algae drying duration on the biodiesel yield was investigated.

Journal ArticleDOI
TL;DR: In this article, a Zr-doped Cu-Zn-Zr-Al (CZZA) catalyst showed excellent performances for methanol synthesis from carbon dioxide and hydrogen such as activity, selectivity and especially stability under mild conditions.
Abstract: Zr-doped Cu-Zn-Zr-Al (CZZA) catalyst showed excellent performances for the methanol synthesis from carbon dioxide and hydrogen such as activity, selectivity and especially stability under mild conditions (such as 230 °C and 3.0 MPa). The catalyst showed excellent tolerance against water vapor. It was found that added alumina promoted the dispersion of Cu whereas it suppressed the reduction of copper oxide. On the other hand, added Zr promoted the catalytic activity of methanol synthesis from CO 2 and suppressed the inhibitive effect of water for the reaction as well as the catalyst deactivation. It was concluded that the methanol formation from CO 2 proceeds through two routes: one is the direct hydrogenation of CO 2 to methanol and another is the one which pass through the CO formation. The Zr-promoted catalyst gave methanol and CO at the selectivity ratio of 0.4 to 0.6, whereas the un-promoted catalyst gave only CO at the initial stage of the reaction. It was claimed that the doped Zr promote the in-situ reduction of oxidized Cu (which should be caused by the reaction with the co-product H 2 O) by H 2 to increase the content of reduced Cu (active site) and thus the catalyst activity. The promoted reductivity of the Zr-containing catalyst prevents the crystal growth of CuO x which cause the irreversible deactivation of catalyst.

Journal ArticleDOI
TL;DR: In this article, a convincing route for formation of initial hydrocarbon pool (HCP) species involving original C-C bonds from dimethyl ether (DME) and/or methanol is illustrated by combining coincident experimental and theoretically calculated results.

Journal ArticleDOI
TL;DR: In this paper, a co-precipitation method was used to synthesize solid CaO-La2O3 mixed metal oxide catalysts for transesterification of Jatropha curcus oil as feedstock to produce biodiesel.

Journal ArticleDOI
TL;DR: In this paper, the performance of transesterification of soybean oil with methanol in the presence of potassium hydroxide, as a catalyst, in a microreactor has been investigated.

Journal ArticleDOI
30 Jan 2014-Fuel
TL;DR: In this article, the feasibility of co-production of methanol and biochar from thermal treatment of pine in a two-stage process; pyrolysis or gasification to produce biochar and volatiles, and the processing of the vatiles to produce methanoline using process data for large-scale conversions based on natural gas.

Journal ArticleDOI
TL;DR: In this paper, a reaction route is proposed where partially hydrogenated guaiacol is decomposed into methanol and phenol, which is further hydrogenated to cyclohexanol.

Journal ArticleDOI
TL;DR: In this paper, a quasicatalytic and a catalytic reaction was shown to be possible at 200°C and below, respectively, with product desorption into gas phase.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the catalytic performance of zirconia modified with KOH as heterogeneous solid base catalyst for transesterification of Silybum marianum (oil content 46%, FFA 0.68% and linoleic acid 65.68%) oil using methanol to biodiesel.

Journal ArticleDOI
TL;DR: Iridium-catalyzed selective α-dimethylation and α-methylation of ketones or phenylacetonitriles, using methanol as the methylating agent, were achieved and this method provides a very convenient direct route to α- methylated ketones, using meethanol.