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Smith LR, Smith PJ, Mugford KS, Douthwaite M, Dummer NF, Willock DJ, Howard M, Knight DW, Taylor SH, Hutchings GJ. New insights for the valorisation of glycerol over MgO catalysts in the gas-phase. Catal Sci Technol 2019. [DOI: 10.1039/c8cy02214c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aqueous glycerol solutions of up to 50 wt% were reacted over magnesium oxide catalysts at temperatures greater than 300 °C, the reactivity of which was compared to catalyst-free reactions.
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Adamik RK, Hernández-Ibáñez N, Iniesta J, Edwards JK, Howe AGR, Armstrong RD, Taylor SH, Roldan A, Rong Y, Malpass-Evans R, Carta M, McKeown NB, He D, Marken F. Platinum Nanoparticle Inclusion into a Carbonized Polymer of Intrinsic Microporosity: Electrochemical Characteristics of a Catalyst for Electroless Hydrogen Peroxide Production. NANOMATERIALS (BASEL, SWITZERLAND) 2018; 8:E542. [PMID: 30021972 PMCID: PMC6071093 DOI: 10.3390/nano8070542] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 07/07/2018] [Accepted: 07/11/2018] [Indexed: 11/17/2022]
Abstract
The one-step vacuum carbonization synthesis of a platinum nano-catalyst embedded in a microporous heterocarbon (Pt@cPIM) is demonstrated. A nitrogen-rich polymer of an intrinsic microporosity (PIM) precursor is impregnated with PtCl₆2- to give (after vacuum carbonization at 700 °C) a nitrogen-containing heterocarbon with embedded Pt nanoparticles of typically 1⁻4 nm diameter (with some particles up to 20 nm diameter). The Brunauer-Emmett-Teller (BET) surface area of this hybrid material is 518 m² g-1 (with a cumulative pore volume of 1.1 cm³ g-1) consistent with the surface area of the corresponding platinum-free heterocarbon. In electrochemical experiments, the heterocarbon-embedded nano-platinum is observed as reactive towards hydrogen oxidation, but essentially non-reactive towards bigger molecules during methanol oxidation or during oxygen reduction. Therefore, oxygen reduction under electrochemical conditions is suggested to occur mainly via a 2-electron pathway on the outer carbon shell to give H₂O₂. Kinetic selectivity is confirmed in exploratory catalysis experiments in the presence of H₂ gas (which is oxidized on Pt) and O₂ gas (which is reduced on the heterocarbon surface) to result in the direct formation of H₂O₂.
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Nowicka E, Hickey NW, Sankar M, Jenkins RL, Knight DW, Willock DJ, Hutchings GJ, Francisco M, Taylor SH. Mechanistic Insights into Selective Oxidation of Polyaromatic Compounds using RICO Chemistry. Chemistry 2018; 24:12359-12369. [PMID: 29790204 DOI: 10.1002/chem.201800423] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Indexed: 11/07/2022]
Abstract
Ruthenium-ion-catalyzed oxidation (RICO) of polyaromatic hydrocarbons (PAHs) has been studied in detail using experimental and computational approaches to explore the reaction mechanism. DFT calculations show that regioselectivity in these reactions can be understood in terms of the preservation of aromaticity in the initial formation of a [3+2] metallocycle intermediate at the most-isolated double bond. We identify two competing pathways: C-C bond cleavage leading to a dialdehyde and C-H activation followed by H migration to the RuOx complex to give diketones. Experimentally, the oxidation of pyrene and phenanthrene has been carried out in monophasic and biphasic solvent systems. Our results show that diketones are the major product for both phenanthrene and pyrene substrates. These diketone products are shown to be stable under our reaction conditions so that higher oxidation products (acids and their derivatives) are assigned to the competing pathway through the dialdehyde. Experiments using 18 O-labelled water do show incorporation of oxygen from the solvents into products, but this may take place during the formation of the reactive RuO4 species rather than directly during PAH oxidation. When the oxidation of pyrene is carried out using D2 O, a kinetic isotope effect (KIE) is observed implying that water is involved in the rate-determining step leading to the diketone products.
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Miedziak PJ, Edwards JK, Taylor SH, Knight DW, Tarbit B, Hutchings GJ. Gold as a Catalyst for the Ring Opening of 2,5-Dimethylfuran. Catal Letters 2018. [DOI: 10.1007/s10562-018-2415-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Davies D, Golunski S, Johnston P, Lalev G, Taylor SH. Dominant Effect of Support Wettability on the Reaction Pathway for Catalytic Wet Air Oxidation over Pt and Ru Nanoparticle Catalysts. ACS Catal 2018. [DOI: 10.1021/acscatal.7b04039] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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31
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Evans CD, Kondrat SA, Smith PJ, Manning TD, Miedziak PJ, Brett GL, Armstrong RD, Bartley JK, Taylor SH, Rosseinsky MJ, Hutchings GJ. The preparation of large surface area lanthanum based perovskite supports for AuPt nanoparticles: tuning the glycerol oxidation reaction pathway by switching the perovskite B site. Faraday Discuss 2018; 188:427-50. [PMID: 27074316 PMCID: PMC5042134 DOI: 10.1039/c5fd00187k] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Gold and gold alloys, in the form of supported nanoparticles, have been shown over the last three decades to be highly effective oxidation catalysts. Mixed metal oxide perovskites, with their high structural tolerance, are ideal for investigating how changes in the chemical composition of supports affect the catalysts' properties, while retaining similar surface areas, morphologies and metal co-ordinations. However, a significant disadvantage of using perovskites as supports is their high crystallinity and small surface area. We report the use of a supercritical carbon dioxide anti-solvent precipitation methodology to prepare large surface area lanthanum based perovskites, making the deposition of 1 wt% AuPt nanoparticles feasible. These catalysts were used for the selective oxidation of glycerol. By changing the elemental composition of the perovskite B site, we dramatically altered the reaction pathway between a sequential oxidation route to glyceric or tartronic acid and a dehydration reaction pathway to lactic acid. Selectivity profiles were correlated to reported oxygen adsorption capacities of the perovskite supports and also to changes in the AuPt nanoparticle morphologies. Extended time on line analysis using the best oxidation catalyst (AuPt/LaMnO3) produced an exceptionally high tartronic acid yield. LaMnO3 produced from alternative preparation methods was found to have lower activities, but gave comparable selectivity profiles to that produced using the supercritical carbon dioxide anti-solvent precipitation methodology.
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Williams C, Carter JH, Dummer NF, Chow YK, Morgan DJ, Yacob S, Serna P, Willock DJ, Meyer RJ, Taylor SH, Hutchings GJ. Selective Oxidation of Methane to Methanol Using Supported AuPd Catalysts Prepared by Stabilizer-Free Sol-Immobilization. ACS Catal 2018. [DOI: 10.1021/acscatal.7b04417] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Armstrong RD, Peneau V, Ritterskamp N, Kiely CJ, Taylor SH, Hutchings GJ. The Role of Copper Speciation in the Low Temperature Oxidative Upgrading of Short Chain Alkanes over Cu/ZSM-5 Catalysts. Chemphyschem 2018; 19:469-478. [DOI: 10.1002/cphc.201701046] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/25/2017] [Indexed: 11/10/2022]
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Chow YK, Dummer NF, Carter JH, Meyer RJ, Armstrong RD, Williams C, Shaw G, Yacob S, Bhasin MM, Willock DJ, Taylor SH, Hutchings GJ. A Kinetic Study of Methane Partial Oxidation over Fe-ZSM-5 Using N2
O as an Oxidant. Chemphyschem 2018; 19:402-411. [DOI: 10.1002/cphc.201701202] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Revised: 12/18/2017] [Indexed: 11/08/2022]
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Albilali R, Douthwaite M, He Q, Taylor SH. The selective hydrogenation of furfural over supported palladium nanoparticle catalysts prepared by sol-immobilisation: effect of catalyst support and reaction conditions. Catal Sci Technol 2018. [DOI: 10.1039/c7cy02110k] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Pd-TiO2 nanoparticles prepared by sol-immobilisation are very active for selective hydrogenation of furfural under mild conditions, and addition of Pt enhances performance to achieve a 95% yield of tetrahydrofurfuryl alcohol.
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Chow YK, Dummer NF, Carter JH, Williams C, Shaw G, Willock DJ, Taylor SH, Yacob S, Meyer RJ, Bhasin MM, Hutchings GJ. Investigating the influence of acid sites in continuous methane oxidation with N2O over Fe/MFI zeolites. Catal Sci Technol 2018. [DOI: 10.1039/c7cy01769c] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Methane oxidation using N2O was carried out with Fe–MFI zeolite catalysts at 300 °C.
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Nowicka E, Clarke TJ, Sankar M, Jenkins RL, Knight DW, Golunski S, Hutchings GJ, Willock DJ, Francisco M, Taylor SH. Oxidation of Polynuclear Aromatic Hydrocarbons using Ruthenium-Ion-Catalyzed Oxidation: The Role of Aromatic Ring Number in Reaction Kinetics and Product Distribution. Chemistry 2017; 24:655-662. [PMID: 29131412 DOI: 10.1002/chem.201704133] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Indexed: 11/12/2022]
Abstract
Oxidation of aromatic hydrocarbons with differing numbers of fused aromatic rings (2-5), have been studied in two solvent environments (monophasic and biphasic) using ruthenium-ion-catalyzed oxidation (RICO). RICO reduces the aromaticity of the polyaromatic core of the molecule in a controlled manner by selective oxidative ring opening. Moreover, the nature of the solvent system determines the product type and distribution, for molecules with more than two aromatic rings. Competitive oxidation between substrates with different numbers of aromatic rings has been studied in detail. It was found that the rate of polyaromatic hydrocarbon oxidation increases with the number of fused aromatic rings. A similar trend was also identified for alkylated aromatic hydrocarbons. The proof-of-concept investigation provides new insight into selective oxidation chemistry for upgrading of polyaromatic molecules.
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Ivars-Barceló F, Hutchings GJ, Bartley JK, Taylor SH, Sutter P, Amorós P, Sanchis R, Solsona B. Relationship between bulk phase, near surface and outermost atomic layer of VPO catalysts and their catalytic performance in the oxidative dehydrogenation of ethane. J Catal 2017. [DOI: 10.1016/j.jcat.2017.08.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Agarwal N, Freakley SJ, McVicker RU, Althahban SM, Dimitratos N, He Q, Morgan DJ, Jenkins RL, Willock DJ, Taylor SH, Kiely CJ, Hutchings GJ. Aqueous Au-Pd colloids catalyze selective CH4oxidation to CH3OH with O2under mild conditions. Science 2017; 358:223-227. [DOI: 10.1126/science.aan6515] [Citation(s) in RCA: 331] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 08/25/2017] [Indexed: 01/22/2023]
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Liu X, Conte M, He Q, Knight DW, Murphy DM, Taylor SH, Whiston K, Kiely CJ, Hutchings GJ. Catalytic Partial Oxidation of Cyclohexane by Bimetallic Ag/Pd Nanoparticles on Magnesium Oxide. Chemistry 2017; 23:11834-11842. [DOI: 10.1002/chem.201605941] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/07/2017] [Indexed: 01/21/2023]
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Smith PJ, Kondrat SA, Carter JH, Chater PA, Bartley JK, Taylor SH, Spencer MS, Hutchings GJ. Supercritical Antisolvent Precipitation of Amorphous Copper-Zinc Georgeite and Acetate Precursors for the Preparation of Ambient-Pressure Water-Gas-Shift Copper/Zinc Oxide Catalysts. ChemCatChem 2017; 9:1621-1631. [PMID: 28706569 PMCID: PMC5485020 DOI: 10.1002/cctc.201601603] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 02/10/2017] [Indexed: 11/17/2022]
Abstract
A series of copper–zinc acetate and zincian georgeite precursors have been produced by supercritical CO2 antisolvent (SAS) precipitation as precursors to Cu/ZnO catalysts for the water gas shift (WGS) reaction. The amorphous materials were prepared by varying the water/ethanol volumetric ratio in the initial metal acetate solutions. Water addition promoted georgeite formation at the expense of mixed metal acetates, which are formed in the absence of the water co‐solvent. Optimum SAS precipitation occurs without water to give high surface areas, whereas high water content gives inferior surface areas and copper–zinc segregation. Calcination of the acetates is exothermic, producing a mixture of metal oxides with high crystallinity. However, thermal decomposition of zincian georgeite resulted in highly dispersed CuO and ZnO crystallites with poor structural order. The georgeite‐derived catalysts give superior WGS performance to the acetate‐derived catalysts, which is attributed to enhanced copper–zinc interactions that originate from the precursor.
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Peneau V, Armstrong RD, Shaw G, Xu J, Jenkins RL, Morgan DJ, Dimitratos N, Taylor SH, Zanthoff HW, Peitz S, Stochniol G, He Q, Kiely CJ, Hutchings GJ. The Low-Temperature Oxidation of Propane by using H2O2and Fe/ZSM-5 Catalysts: Insights into the Active Site and Enhancement of Catalytic Turnover Frequencies. ChemCatChem 2017. [DOI: 10.1002/cctc.201601241] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Smith PJ, Kondrat SA, Chater PA, Yeo BR, Shaw GM, Lu L, Bartley JK, Taylor SH, Spencer MS, Kiely CJ, Kelly GJ, Park CW, Hutchings GJ. A new class of Cu/ZnO catalysts derived from zincian georgeite precursors prepared by co-precipitation. Chem Sci 2017; 8:2436-2447. [PMID: 28451351 PMCID: PMC5369406 DOI: 10.1039/c6sc04130b] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 12/29/2016] [Indexed: 11/22/2022] Open
Abstract
Zincian georgeite, an amorphous copper–zinc hydroxycarbonate, has been prepared by co-precipitation using acetate salts and ammonium carbonate.
Zincian georgeite, an amorphous copper–zinc hydroxycarbonate, has been prepared by co-precipitation using acetate salts and ammonium carbonate. Incorporation of zinc into the georgeite phase and mild ageing conditions inhibits crystallisation into zincian malachite or aurichalcite. This zincian georgeite precursor was used to prepare a Cu/ZnO catalyst, which exhibits a superior performance to a zincian malachite derived catalyst for methanol synthesis and the low temperature water–gas shift (LTS) reaction. Furthermore, the enhanced LTS activity and stability in comparison to that of a commercial Cu/ZnO/Al2O3 catalyst, indicates that the addition of alumina as a stabiliser may not be required for the zincian georgeite derived Cu/ZnO catalyst. The enhanced performance is partly attributed to the exclusion of alkali metals from the synthesis procedure, which are known to act as catalyst poisons. The effect of residual sodium on the microstructural properties of the catalyst precursor was investigated further from preparations using sodium carbonate.
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Kondrat SA, Smith PJ, Carter JH, Hayward JS, Pudge GJ, Shaw G, Spencer MS, Bartley JK, Taylor SH, Hutchings GJ. The effect of sodium species on methanol synthesis and water–gas shift Cu/ZnO catalysts: utilising high purity zincian georgeite. Faraday Discuss 2017; 197:287-307. [DOI: 10.1039/c6fd00202a] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effect of sodium species on the physical and catalytic properties of Cu/ZnO catalysts derived from zincian georgeite has been investigated. Catalysts prepared with <100 ppm to 2.1 wt% Na+, using a supercritical CO2 antisolvent technique, were characterised and tested for the low temperature water–gas shift reaction and also CO2 hydrogenation to methanol. It was found that zincian georgeite catalyst precursor stability was dependent on the Na+ concentration, with the 2.1 wt% Na+-containing sample uncontrollably ageing to malachite and sodium zinc carbonate. Samples with lower Na+ contents (<100–2500 ppm) remained as the amorphous zincian georgeite phase, which on calcination and reduction resulted in similar CuO/Cu particle sizes and Cu surface areas. The aged 2.1 wt% Na+ containing sample, after calcination and reduction, was found to comprise of larger CuO crystallites and a lower Cu surface area. However, calcination of the high Na+ sample immediately after precipitation (before ageing) resulted in a comparable CuO/Cu particle size to the lower (<100–2500 ppm) Na+ containing samples, but with a lower Cu surface area, which indicates that Na+ species block Cu sites. Activity of the catalysts for the water–gas shift reaction and methanol yields in the methanol synthesis reaction correlated with Na+ content, suggesting that Na+ directly poisons the catalyst. In situ XRD analysis showed that the ZnO crystallite size and consequently Cu crystallite size increased dramatically in the presence of water in a syn-gas reaction mixture, showing that stabilisation of nanocrystalline ZnO is required. Sodium species have a moderate effect on ZnO and Cu crystallite growth rate, with lower Na+ content resulting in slightly reduced rates of growth under reaction conditions.
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Iqbal S, Davies TE, Hayward JS, Morgan DJ, Karim K, Bartley JK, Taylor SH, Hutchings GJ. Fischer Tropsch Synthesis using promoted cobalt-based catalysts. Catal Today 2016. [DOI: 10.1016/j.cattod.2016.04.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Xu J, Armstrong RD, Shaw G, Dummer NF, Freakley SJ, Taylor SH, Hutchings GJ. Continuous selective oxidation of methane to methanol over Cu- and Fe-modified ZSM-5 catalysts in a flow reactor. Catal Today 2016. [DOI: 10.1016/j.cattod.2015.09.011] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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49
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Da Ros S, Jones MD, Mattia D, Pinto JC, Schwaab M, Noronha FB, Kondrat SA, Clarke TC, Taylor SH. Ethanol to 1,3-Butadiene Conversion by using ZrZn-Containing MgO/SiO2
Systems Prepared by Co-precipitation and Effect of Catalyst Acidity Modification. ChemCatChem 2016. [DOI: 10.1002/cctc.201600331] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Kondrat SA, Smith PJ, Wells PP, Chater PA, Carter JH, Morgan DJ, Fiordaliso EM, Wagner JB, Davies TE, Lu L, Bartley JK, Taylor SH, Spencer MS, Kiely CJ, Kelly GJ, Park CW, Rosseinsky MJ, Hutchings GJ. Stable amorphous georgeite as a precursor to a high-activity catalyst. Nature 2016; 531:83-7. [PMID: 26878237 DOI: 10.1038/nature16935] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 12/08/2015] [Indexed: 11/09/2022]
Abstract
Copper and zinc form an important group of hydroxycarbonate minerals that include zincian malachite, aurichalcite, rosasite and the exceptionally rare and unstable--and hence little known and largely ignored--georgeite. The first three of these minerals are widely used as catalyst precursors for the industrially important methanol-synthesis and low-temperature water-gas shift (LTS) reactions, with the choice of precursor phase strongly influencing the activity of the final catalyst. The preferred phase is usually zincian malachite. This is prepared by a co-precipitation method that involves the transient formation of georgeite; with few exceptions it uses sodium carbonate as the carbonate source, but this also introduces sodium ions--a potential catalyst poison. Here we show that supercritical antisolvent (SAS) precipitation using carbon dioxide (refs 13, 14), a process that exploits the high diffusion rates and solvation power of supercritical carbon dioxide to rapidly expand and supersaturate solutions, can be used to prepare copper/zinc hydroxycarbonate precursors with low sodium content. These include stable georgeite, which we find to be a precursor to highly active methanol-synthesis and superior LTS catalysts. Our findings highlight the value of advanced synthesis methods in accessing unusual mineral phases, and show that there is room for exploring improvements to established industrial catalysts.
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