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News Article | May 16, 2017
Site: www.prweb.com

Rigaku Corporation has published an application report on its global website demonstrating the utility of X-ray diffraction (XRD) in the analysis of complex organic mixtures. The analysis described was performed using the Rigaku MiniFlex general purpose X-ray diffractometer and highlights the capacities of the instrument’s analysis software. The ingredients of food components can be difficult to identify. The example presented in the article describes the analysis of pancake mix. In this case, primary ingredients such as brown sugar, baking powder, and flour are the important factors to control in the production process, rather than the molecular compounds that make up the ingredients. Phase identification using X-ray diffraction involves the collection of XRD patterns on unknown samples and comparing them to patterns obtained from known materials. Although the primary database for these XRD patterns is compiled and maintained by the International Center for Diffraction Data (ICDD), the preferred XRD patterns for the primary ingredients may not all be present in the database. In such cases, the MiniFlex analysis software allows users to make their own databases based on user- collected patterns from common or significant materials in the process. Phase identification and quality control of the pancake mix can therefore be done by collecting XRD patterns of the individual ingredients and adding them to the user database of the software. The results displayed in the report are derived from the individual raw ingredients being scanned and overlaid. Each of the individual raw materials was scanned and the patterns were saved to a database. The results show the overlay of newly added patterns to the database with the original XRD pancake mix pattern, confirming the identity of the individual compounds. The pancake article, along with other food science-related XRD analyses, can be seen at https://www.rigaku.com/en/products/xrd/miniflex/apps/2. About Rigaku Since its inception in Japan in 1951, Rigaku has been at the forefront of analytical and industrial instrumentation technology. Rigaku and its subsidiaries form a global group focused on general-purpose analytical instrumentation and the life sciences. With hundreds of major innovations to their credit, Rigaku companies are world leaders in X-ray spectrometry, diffraction, and optics, as well as small molecule and protein crystallography and semiconductor metrology. Today, Rigaku employs over 1,400 people in the manufacturing and support of its analytical equipment, which is used in more than 90 countries around the world supporting research, development, and quality assurance activities. Throughout the world, Rigaku continuously promotes partnerships, dialog, and innovation within the global scientific and industrial communities. For further information, contact:


Kaduk J.A.,North Central College | Gindhart A.M.,ICDD | Blanton T.N.,ICDD
Powder Diffraction | Year: 2016

The crystal structure of norgestimate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Norgestimate crystallizes in space group P212121 (#19) with a = 11.523 67(9), b = 16.130 72(20), c = 22.247 93(20) Å, V = 4135.56(7) Å3, and Z = 8. There are two independent molecules in the asymmetric unit, with opposite conformations of the acetate groups. Molecule 2 is 7.3 kcal mole−1 lower in energy than molecule 1, and is in the minimum energy conformation. The hydroxyimine groups form O–H⋯O hydrogen bonds to the acetate carbonyl groups, resulting in two separate C(15) chains along the b-axis. The powder pattern is included in the Powder Diffraction File™ as entry 00-064-1503. Copyright © International Centre for Diffraction Data 2016


Kaduk J.A.,Illinois Institute of Technology | Crowder C.E.,ICDD | Zhong K.,ICDD
Powder Diffraction | Year: 2015

The crystal structure of folic acid dihydrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Folic acid dihydrate crystallizes in space group P212121 (#19) with a = 7.275 78(3), b = 8.632 17(4), c = 32.417 19(22) Å, V = 2035.985(18) Å3, and Z = 4. The structure is dominated by a three-dimensional network of hydrogen bonds. The dicarboxylic acid side chain occurs in a bent conformation, helping explain the ability of folate derivatives to coordinate metal cations. The powder pattern has been submitted to ICDD for inclusion in future releases of the Powder Diffraction File™. © 2014 International Centre for Diffraction Data.


Kaduk J.A.,Illinois Institute of Technology | Zhong K.,ICDD | Gindhart A.M.,ICDD | Blanton T.N.,ICDD
Powder Diffraction | Year: 2016

The crystal structure of mupirocin Form I has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Mupirocin Form I crystallizes in space group P21 (#4) with a = 12.562 81(16), b = 5.103 63(4), c = 21.713 34(29) Å, β = 100.932(1)°, V = 1366.91(2) Å3, and Z = 2. Although the three hydroxyl groups and the carboxylic acid participate in a three-dimensional hydrogen bond network, the crystal energy appears to be dominated by van der Waals interactions. The Rietveld-refined and density functional optimized structures differ significantly. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™. Copyright © International Centre for Diffraction Data 2016


Kaduk J.A.,Illinois Institute of Technology | Zhong K.,ICDD | Blanton T.N.,ICDD
Powder Diffraction | Year: 2015

The crystal structure of rilpivirine has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Rilpivirine crystallizes in space group P21/c (#14) with a = 8.39049(3), b = 13.89687(4), c = 16.03960(6) Å, β = 90.9344(3)°, V = 1869.995(11) Å3, and Z = 4. The most prominent features of the structure are N-H···N hydrogen bonds. These form a R2,2(8) pattern which, along with C1,1(12) and longer chains, yield a three-dimensional hydrogen bond network. The powder pattern has been submitted to International Centre for Diffraction Data, ICDD, for inclusion in future releases of the Powder Diffraction File™. © International Centre for Diffraction Data 2015.


Kaduk J.A.,Illinois Institute of Technology | Zhong K.,ICDD | Gindhart A.M.,ICDD | Blanton T.N.,ICDD
Powder Diffraction | Year: 2016

The crystal structure of choline fenofibrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Choline fenofibrate crystallizes in space group Pbca (#61) with a = 12.341 03(2), b = 28.568 70(6), c = 12.025 62(2) Å, V = 4239.84(1) Å3, and Z = 8. The hydroxyl group of the choline anion makes a strong hydrogen bond to the ionized carboxylate group of the fenofibrate anion. Together with C–H···O hydrogen bonds, these link the cations and anions into layers parallel to the ac-plane. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™. Copyright © International Centre for Diffraction Data 2016


Kaduk J.A.,Illinois Institute of Technology | Zhong K.,ICDD | Gindhart A.M.,ICDD | Blanton T.N.,ICDD
Powder Diffraction | Year: 2016

The crystal structure of paliperidone has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Paliperidone crystallizes in space group P21/n (# 14) with a = 14.151 58(6), b = 21.537 80(9), c = 6.913 26(2) Å, β = 92.3176(2)°, V = 2105.396(13) Å3, and Z = 4. The unit-cell volume at 295 K is 1.5% larger than at 200 K, but the expansion is anisotropic; the b-axis is nearly constant at the two temperatures, while the a- and c-axes expand by 0.71 and 0.87%, respectively. There is only one significant hydrogen (H)-bond in the crystal structure. This H-bond is between the hydroxyl group O31–H58 and the ketone oxygen O25. The result is a chain along the c-axis with graph set C1,1(7). In addition to this H-bond, the molecular packing is dominated by van der Waals attractions. The powder pattern is included in the Powder Diffraction File™ as entry 00-064-1497. Copyright © International Centre for Diffraction Data 2016


Kaduk J.A.,Illinois Institute of Technology | Zhong K.,ICDD | Gindhart A.M.,ICDD | Blanton T.N.,ICDD
Powder Diffraction | Year: 2016

The crystal structure of citalopram hydrobromide has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory techniques. Citalopram hydrobromide crystallizes in space group P21/c (#14) with a = 10.766 45(6), b = 33.070 86(16), c = 10.892 85(5) Å, β = 90.8518(3)°, V = 3878.03(4) Å3, and Z = 8. N–H⋯Br hydrogen bonds are important to the structure, but the crystal energy is dominated by van der Waals attraction. The powder pattern was submitted to International Centre for Diffraction Data for inclusion in the Powder Diffraction File™. Copyright © International Centre for Diffraction Data 2016


News Article | December 7, 2016
Site: www.marketwired.com

THUNDER BAY, ONTARIO--(Marketwired - Dec. 7, 2016) - Alset Energy Corp. (TSX VENTURE:ION) ("Alset" or "the Company") is pleased to announce the laboratory results of 30 samples selected from stored historical sampling efforts completed by LitioMex (2009-2011), the former property owner, on three of the Mexican salars, La Salada, Santa Clara, and Caliguey. The laboratory work included a check or "head" assay followed by quantitative X-ray diffraction analysis and a second assay on the less than 2 micron size fraction of the sample. The purpose of the X-ray diffraction was to determine the clay mineral species and their abundance. The original samples were part of a work program conducted by the previous owners whereby 5m holes were dug in the salars on a 100m x 100m grid with five 1m samples collected from each hole and submitted for multi-element analyses. The historical values returned from Inspectorate laboratory for the 30 samples ranged from 411 to 2590ppm lithium compared to the recent results from Activation Laboratories ("Actlabs") on behalf of Alset which ranged from 340 to 1680ppm lithium. Both laboratories used an induced coupled plasma (ICP) procedure with a four-acid total digestion. Overall the results from Inspectorate seem a bit higher than those produced by Actlabs and may be a result of the remaining portion of each sample used by Actlabs being much smaller. The most important aspect of the current ongoing laboratory work is the XRD (x-ray diffraction) results listed in the table below. Smectite is a group of clay minerals of which the lithium-bearing mineral hectorite is included. Of the 30 samples submitted, no smectite was detected in 12 and only trace was detected in 2 samples. The samples with the highest concentration of smectite, which may or may not be hectorite, came from the Caliguey salar where Mexico's former Mineral Resource Council sampling of fluid in the salar returned values of 1.2 to 2.1% lithium (see Alset PR September 1, 2016). The evidence suggests that the vast majority of the lithium is not held in hectorite clay where it is difficult and expensive to extract. Table 1: Mineral abundances in samples in the <2 micron size fraction: Note: n.d. = no detection,Y = present but relative proportions of smectite and illite were not calculated for samples containing poorly crystalline smectite-like mineral, all values of elements above are percentages of total sample composition. In addition to the promising lithium grades, the potassium was equally as encouraging and potentially represents an important co-product with economic significance. Historical values returned from Inspectorate varied from 1.56 to 10% potassium and 1.57 to 4.78% from Actlabs for the same samples. Only background levels of uranium were detected and will not present any complications. Another interesting aspect of the samples was that they all contained silver, ranging from 0.5 ppm to 4.3 ppm (gpt). Geothermal activity is one of the first order characteristics in the preliminary deposit model for formation of lithium brines. The silica sinters and carbonate growth textures at the Mexican salars are ample evidence of the geothermal activity, specifically epithermal processes. It is worth noting that this same geological process is also what typically produces many gold-silver deposits and these Mexican salars are situated in one of the most prolific silver producing regions in the world. The Company plans on following up on the silver potential of our projects as well. Allan Barry Laboucan, President and CEO of Alset stated: "We have just started the first phase in testing the chemical composition of our salars and our team is delighted with the results. In addition to the encouraging lithium results the potassium grades are encouraging as well. Currently Mexico imports all of its potassium and a domestic source would not only be a cost saver for Mexico but would create job opportunities in a crucial commodity for the farming sector. Furthermore, the silver results suggest there may be potential for precious metals as well and further work is required to assess this potential. We are still in the very early stages of assessing the realistic potential of the projects. I'm excited about these results and look forward to the upcoming leach tests on these samples prior to follow-up drilling at several of the salars in the early part of 2017." Methodolgy: Thirty samples were submitted to Activation Laboratories (Zacatecas, Mexico and Ancastor, Ontario, Canada) for quantitative X-ray diffraction analysis including clay speciation. The quantitative XRD analysis was performed on a pulverized bulk sample. A portion of each pulverized sample was mixed with corundum and packed into a standard holder. Corundum was added as an internal standard, to determine the amount of poorly crystalline and X-ray amorphous material. For clay speciation analysis, a portion of each sample was dispersed in distilled water and clay minerals in the < 2 μm size fraction separated by gravity settling of particles in suspension. Oriented slides of the < 2 μm size fraction were prepared by placing a portion of the suspension onto a glass slide. In order to identify expandable clay minerals, the oriented slides were analyzed air-dry and after treatment with ethylene glycol. The X-ray diffraction analysis was performed on a Panalytical X'Pert Pro diffractometer equipped with Cu X-ray source and an X'Celerator detector and operating at the following conditions: 40 kV and 40 mA; range 5-70 deg 2θ for random specimens and 3 - 35 deg 2θ for oriented specimens; step size 0.017 deg 2θ; time per step 50.165 sec; fixed divergence slit, angle 0.5° and 0.250; sample rotation 1 rev/sec. The X'Pert HighScore plus software along with the PDF4/Minerals ICDD database were used for mineral identification. The quantities of the crystalline mineral phases were determined using Rietveld method. The Rietveld method is based on the calculation of the full diffraction pattern from crystal structure information. The amount of poorly crystalline minerals such as smectite could not be calculated by the Rietveld refinement. Instead, the amounts of the crystalline minerals were recalculated based on a know percent of corundum and the remainder to 100 % was considered poorly crystalline and X-ray amorphous material. The relative proportions of the clay minerals in the < 2 μm size fraction were calculated using ratios of their basal-peak areas. Clinton Barr, PGeo, Vice-President of Exploration for Alset Energy Corp., is the qualified person responsible for this release and has prepared, supervised and approved the preparation of the scientific and technical disclosure contained within the release. Alset Energy is a TSX-V listed junior exploration company focused on exploring and acquiring mineral properties containing the metals needed by today's high-tech industries. The Company is actively exploring in Mexico and Canada. On behalf of the Board of Directors of Alset Energy Corp., THE TSX VENTURE EXCHANGE HAS NOT REVIEWED AND DOES NOT ACCEPT RESPONSIBILITY FOR THE ADEQUACY OR ACCURACY OF THIS RELEASE. The information contained herein contains "forward-looking statements" within the meaning of applicable securities legislation. Forward-looking statements relate to information that is based on assumptions of management, forecasts of future results, and estimates of amounts not yet determinable. Any statements that express predictions, expectations, beliefs, plans, projections, objectives, assumptions or future events or performance are not statements of historical fact and may be "forward-looking statements." Forward-looking statements are subject to a variety of risks and uncertainties which could cause actual events or results to differ from those reflected in the forward-looking statements, including, without limitation: risks related to failure to obtain adequate financing on a timely basis and on acceptable terms; risks related to the outcome of legal proceedings; political and regulatory risks associated with mining and exploration; risks related to the maintenance of stock exchange listings; risks related to environmental regulation and liability; the potential for delays in exploration or development activities or the completion of feasibility studies; the uncertainty of profitability; risks and uncertainties relating to the interpretation of drill results, the geology, grade and continuity of mineral deposits; risks related to the inherent uncertainty of production and cost estimates and the potential for unexpected costs and expenses; results of prefeasibility and feasibility studies, and the possibility that future exploration, development or mining results will not be consistent with the Company's expectations; risks related to gold price and other commodity price fluctuations; and other risks and uncertainties related to the Company's prospects, properties and business detailed elsewhere in the Company's disclosure record. Should one or more of these risks and uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those described in forward-looking statements. Investors are cautioned against attributing undue certainty to forward-looking statements. These forward looking statements are made as of the date hereof and the Company does not assume any obligation to update or revise them to reflect new events or circumstances. Actual events or results could differ materially from the Company's expectations or projections.


News Article | March 4, 2016
Site: www.nature.com

SAS method for preparing georgeite and zincian georgeite. Copper(ii) acetate monohydrate (4 mg ml−1) and zinc(ii) acetate dihydrate (2.16 mg ml−1) (Sigma Aldrich ≥ 99% Puriss) were dissolved in ethanol (reagent grade, Fischer Scientific) containing 0 vol%, 5 vol% or 10 vol% deionized water. Smithsonite ZnCO was prepared with zinc(ii) acetate dehydrate (2.16 mg ml−1) in a 10 vol% water and ethanol solution. SAS experiments were performed using apparatus manufactured by Separex. CO (from BOC) was pumped through the system (held at 110 bar, 40 °C) via the outer part of a coaxial nozzle at a rate of 6 kg h−1. The metal salt solution was concurrently pumped through the inner nozzle, using an Agilent HPLC pump at a rate of 6.4 ml min−1. The resulting precipitate was recovered on a stainless steel frit, while the CO –solvent mixture passed down stream, where the pressure was decreased to separate the solvent and CO . The precipitation vessel has an internal volume of 1 litre. Precipitation was carried out for 120 minutes, and followed by a purge of the system with ethanol–CO for 15 minutes, then CO for 60 minutes under 110 bar and 40 °C. The system was then depressurized and the dry powder collected. Recovered samples were placed in a vacuum oven at 40 °C for 4 hours to remove any residual solvent. Approximately 1.5 g of georgeite is prepared during the 120-minute duration of solution precipitation. Co-precipitation method for preparing malachite and zincian malachite precursors for the standard methanol-synthesis catalysts. The procedure was performed via a semi-continuous process, using two peristaltic pumps to maintain pH. Copper(ii) nitrate hydrate and zinc(ii) nitrate hydrate solutions in deionized water were prepared with copper/zomc molar ratios of 1/0, 1/1 and 2/1. The premixed metal solution (5 l, ~0.5 g ml−1) was preheated along with a separate 5 l solution of 1.5 M sodium carbonate. The mixed metals were precipitated by combining the two solutions concurrently at 65 °C, with the pH being held between 6.5 and 6.8. The precipitate would spill over from the small precipitation pot into a stirred ageing vessel, held at 65 °C. The precipitate was aged for 15 minutes after all precursor solutions had been used. The precipitate was than filtered and washed to minimize sodium content. The sample was washed with 6 l of hot deionized water, and the sodium content monitored using a photometer. The washing process was repeated until the sodium content showed no change. The sample was then dried at 110 °C for 16 hours. Samples were calcined for 6 hours at 300 °C or 450 °C in a tube furnace under static air. The ramp rate used to reach the desired temperature was 1 °C min−1. Catalyst testing was performed with 0.5 g of the calcined catalyst, pelleted and ground to a sieve fraction of 0.6–1 mm for both the methanol-synthesis and the LTS test reactions. The catalysts were reduced in situ using a 2% H /N gas mixture at 225 °C (ramp rate 1 °C min–1), before the reaction gases were introduced. Data reported for the industrial standards are the mean value from four repeat experiments. Error bars are based on the standard deviation from the mean values. Methanol synthesis. Testing was carried out in a single-stream, six-fixed-bed reactor with an additional bypass line. After reduction, the catalysts were then subjected to synthesized syngas (CO/CO /H /N  = 6.9/2/67/17.8) at 3.5 l h−1, 25 bar pressure and 195 °C. In-line gas analysis was performed using an FT-IR spectrometer, which detected CO, CO , H O and CH OH. Downstream of the catalyst beds, knockout pots collected effluent produced from the reaction. The contents were collected after each test run and analysed using gas chromatography to evaluate the selectivity of catalysts. The total system flow was maintained using the bypass line. LTS. Testing was performed in six parallel fixed-bed reactors with a single stream feed and an additional bypass line. After reduction, the catalysts were subjected to synthetic syngas (CO/CO /H /N  = 1/4/13.75/6.25) at 27.5 bar pressure and 220 °C. The reactant gas stream was passed though vaporized water to give a water composition of 50 vol%. This gives a total gas flow of H O/CO/CO /H /N  = 50/2/8/27.5/12.5. The standard mass hourly space velocity (MHSV) used for testing was 75,000 k h−1 kg−1. In-line IR analysis was carried out to measure CO conversion. Selectivity was determined by the methanol content within the knockout pots downstream of the reactors. Space and mass velocity variation tests were performed at 65 hours’ time-on-line by altering the flow for each catalyst bed. Relative activities were calculated by altering the flow for each catalyst bed in order to achieve 75% CO conversion after 75 hours’ time-on-line. The total system flow was maintained using the bypass line. Powder X-ray diffraction (XRD). Measurements were performed using a PANalytical X’pert Pro diffractometer with a Ni-filtered CuK radiation source operating at 40 kV and 40 mA. Patterns were recorded over the range of 10–80° 2θ using a step size of 0.016°. All patterns were matched using the International Centre for Diffraction Data (ICDD) database. An in situ Anton Parr XRK900 cell (with an internal volume of ~0.5 l) was used to monitor the formation of metallic copper during the reduction of the CuO/ZnO materials. A flow of 2% H /N (60 ml min-1) was passed through the sample bed while the cell was heated to 225 °C (ambient temperature to 125 °C, ramp rate10 °C min−1; 125–225 °C, ramp rate 2 °C min−1). The sample was then cooled to room temperature and a 20–100° 2θ scan performed. Copper crystallite size was estimated from a peak-broadening analysis of the XRD pattern using Topas Academic30, and the volume-weighted column height (L ) was calculated according to ref. 31. X-ray absorption fine-edge spectroscopy (XAFS). K-edge XAFS studies of copper and zinc were carried out on the B18 beamline at the Diamond Light Source, Didcot, UK. Measurements were performed using a quick extended (QE) XAFS set-up with a fast-scanning silicon (111) double-crystal monochromator. The time resolution of the spectra reported herein was 1 minute per spectrum (k  = 14), and on average three scans were acquired to improve the signal-to-noise ratio of the data. All ex situ samples were diluted with cellulose and pressed into pellets to optimize the effective-edge step of the XAFS data and measured in transmission mode using ion-chamber detectors. All transmission XAFS spectra were acquired concurrently with the appropriate reference foil (copper or zinc) placed between I and I XAS data processing, and EXAFS analysis were performed using IFEFFIT32 with the Horae package33 (Athena and Artemis). The FT data were phase-corrected for oxygen. The amplitude-reduction factor, S2 , was derived from EXAFS data analysis of a known copper reference compound, namely tenorite (CuO). For the fitting of the local coordination geometry of georgeite and malachite, the Jahn–Teller distorted copper–oxygen bond was difficult to observe because of thermal disorder, and so was fixed in the model. X-ray pair distribution function (PDF) analysis. Synchrotron X-ray PDF data were collected on the 11-ID-B beamline at the Advanced Photon Source, Argonne National Laboratory, and on the I15 beamline at the Diamond Light Source. Powder samples were packed into kapton capillaries with an internal diameter of 1 mm. Room-temperature powder X-ray diffraction data were collected at a wavelength of 0.2114 Å (11-ID-B) and 0.1620 Å (I15) using the Rapid Acquisition PDF method34. The scattering data (0.5 ≤ Q ≤ 22 Å−1) were processed into PDF data using the program GudrunX35. Two notations of PDF data are presented in this manuscript: G(r) and D(r) (ref. 36). The total radial distribution function, G(r), is the probability of finding a pair of atoms, weighted by the scattering power of the pair, at a given distance, r; it is the Fourier transform experimentally determined total structure factor. D(r) is re-weighted to emphasize features at high r, such that D(r) = 4πrρ G(r), where ρ is the average number density of the material (in atoms Å−1). Fourier transform-infrared spectroscopy (FT-IR). Analysis was carried out using a Jasco FT/IR 660 Plus spectrometer in transmission mode over a range of 400–4,000 cm–1. Catalysts were supported in a pressed KBr disk. Raman spectroscopy. Raman spectra were obtained using a Renishaw inVia spectrometer equipped with an argon ion laser (λ = 514 nm). Thermal gravimetric analysis (TGA). TGA measurements were performed using a SETARAM Labsys analyser with sample masses of about 20 mg, at 1 °C min−1 under air with a flow rate of 20 ml min−1. Evolved gas analysis (EGA). EGA experiments were performed using a Hiden CATLAB under the same conditions used in the TGA experiments. Copper surface area analysis. This was determined by reactive frontal chromatography. Catalysts were crushed and sieved to a particle size of 0.6–1 mm and packed into a reactor tube. The catalyst was purged under helium for 2 minutes at 70 °C before being heated under a 5% H reduction gas to 230 °C (8 °C min−1) for 3 hours. The catalyst was then cooled to 68 °C under helium before the dilute 2.5% N O reaction gas was added with a flow rate of 65 ml min−1. The formation of N from the surface oxidation of the copper catalyst by N O was measured downstream using a thermal conductivity detector (TCD). Once the surface of the copper is fully oxidized, there is a breakthrough of N O, detected on the TCD. From this, the number of oxygen atoms that are chemisorbed on the copper surface can be determined. The number of exposed surface copper atoms and the copper surface area can then be derived. Quoted surface areas are calculated using discharged sample mass. Note that recent work37, 38 has shown that, if the catalyst is exposed to partial pressures of H exceeding 0.05 bar, then partial reduction of ZnO at the copper interface can occur. This will affect copper surface area results, owing to N O oxidizing both copper and ZnO . In these cases, alternative techniques, such as a H thermal conductivity detector, will give more accurate data with respect to copper surface area37, 38. Copper surface area analysis after exposure to LTS conditions. Copper surface area analysis of the fresh catalysts were carried out on a Quantachrome ChemBET 3000. Sample (100 mg) was packed into a stainless-steel U-tube and purged with high-purity helium for 5 minutes. Samples were reduced using 10% H /Ar (30 ml min−1) heated to 140 °C at 10 °C min−1, before heating further to 225 °C at 1 °C min−1. The resulting catalyst was held at this temperature for 20 minutes to ensure that complete reduction took place. Note that, under this partial pressure of H , it has been reported that ZnO species in contact with copper can partially reduce37, 38. Residual H was flushed from the system by switching the gas line back over to helium (80 ml min−1), while holding the sample at 220 °C for another 10 minutes. The temperature was then reduced to 65 °C for N O pulsing (BOC AA Grade). A programme of 12 pulses of 113 μl N O with a 5-minute stabilization time between pulses was carried out, followed by three pulses of N for calibration. Unreacted N O was trapped before reaching the detector using a molecular sieve 5A (pelleted, 1.6 mm, Sigma Aldrich) trap. The copper surface area was determined from the amount of N emitted and the post-reaction analysis of catalyst mass, as follows: where N is the Avogadro constant, 6.022 × 1023 (atoms). The key assumptions are that the amount of N emitted amounts to half a monolayer’s coverage of oxygen, and that the surface density of copper is 1.47 × 1019 (atoms m−2). The volume of N produced was quantified using a TCD. After copper surface area analysis, the samples were kept under N and transferred to an LTS reactor. Ageing was carried out in a single fixed-bed reactor equipped with a bypass line. CO, N , CO and H were introduced to the catalyst bed via mass-flow controllers (Bronkhorst). Water of high-performance liquid chromatography (HPLC) grade was passed through a liquid-flow controller (Bronkhorst) and then into a controlled evaporator mixer (Bronkhorst) that was heated to 140 °C. N was fed through the vaporized water to give a dilute syngas mixture (H O/CO/CO /H /N  = 25/1/4/13.75/56.25). This mixture was introduced at 220 °C after re-reduction of the catalyst. The gas flows were controlled to achieve an MHSV of 30,000 l h−1 kg−1. After ageing for 40 hours, the samples were transferred back to the Quantachrome ChemBET Chemisorption analyser, whereby, after re-reduction, the copper surface areas of the aged catalysts were measured, as described above. Scanning transmission electron microscopy (STEM). Samples for STEM characterization were dry-dispersed onto holey carbon TEM grids. They were examined in an aberration-corrected JEOL ARM-200CF scanning transmission electron microscope operating at 200 kV in bright-field and dark-field STEM imaging modes. Reliable electron microscopy results could be obtained only from the set of zincian-georgeite- and zincian-malachite-derived materials, as these were found to be stable under the vacuum environment of the microscope, and largely unaffected by electron-beam irradiation. By way of contrast, the copper-only georgeite precursor materials were highly unstable under vacuum conditions (even without electron-beam irradiation), turning from a blue to dark-green colour, probably owing to the loss of occluded water. The corresponding zincian-georgeite materials showed no such colour transformation under vacuum. Environmental transmission electron microscopy (ETEM). Samples for reduction during characterization by ETEM were dry-dispersed on heater chips (DensSolution trough hole) and then mounted on a DensSolution SH30 heating holder. The holder with sample was inserted into an FEI Titan 80-300 environmental transmission electron microscope operated at 300 kV (ref. 39) . The reduction of the samples was performed in situ as follows, for both the georgeite and the malachite precursors: a flow of H was let into the microscope, building up a pressure of 2 mbar. The sample was heated from room temperature to 150 °C using a heating ramp rate of 10 °C min−1. The final heating to 225 °C was done at 1 °C min−1. The oxidation state of copper was monitored by electron energy-loss spectroscopy (EELS) during the reduction treatment using a Gatan Tridiem 866 spectrometer attached to the microscope. After an extended in situ treatment of several hours at 225 °C, phase-contrast lattice imaging was performed at elevated temperature in an H atmosphere for both the georgeite and malachite samples, and recorded using a Gatan US 1000 charge-coupled-device camera. X-ray photoelectron spectroscopy (XPS). A Kratos Axis Ultra DLD system was used to collect XPS spectra, using a monochromatic Al K X-ray source operating at 120 W. Data were collected with pass energies of 160 eV for survey spectra, and 40 eV for the high-resolution scans. The system was operated in the Hybrid mode, using a combination of magnetic immersion and electrostatic lenses and acquired over an area approximately 300 × 700 μm2. A magnetically confined charge-compensation system was used to minimize charging of the sample surface, and the resulting spectra were calibrated to the C(1 s) line at 284.8 eV; all spectra were taken with a 90° take-off angle. A base pressure of ~1 × 10−9 Torr was maintained during collection of the spectra. Gas treatments were performed in a Kratos catalysis cell, which mimics the conditions of a normal reactor vessel, allowing the re-creation of reactor conditions and analysis of the chemical changes taking place on the catalyst surface. Briefly, the cell consists of a fused quartz reactor vessel contained within a stainless-steel vacuum chamber (base pressure ~10−8 Torr after baking). Samples were heated at a controlled ramp rate of 2 °C min−1 to a temperature of 225 °C using a eurotherm controller. The catalysts were exposed to an atmosphere of 2% H in nitrogen with a flow rate of 30 ml min−1, controlled using MKS mass flow controllers during the heating ramp, during the 20-minute isotherm at 225 °C, and also while the catalyst was cooled to 25 °C. The samples were analysed before and after gas treatment without breaking the vacuum. Inductively coupled plasma mass spectrometry (ICP-MS) and carbon–hydrogen–nitrogen (CHN) analysis. These analyses were provided as a commercial service by Warwick Analytical Services. Helium pycnometry. This analysis was provided as a commercial service by MCA Services.

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