scholarly journals Selective electrocatalytic hydrogenation of bio-oil to oxygenated chemicals via suppression of deoxygenation

2021 ◽  
Author(s):  
Tao Peng ◽  
Taotao Zhuang ◽  
Yu Yan ◽  
Jin Qian ◽  
Graham Dick ◽  
...  
Keyword(s):  
Room Temperature ◽  
Ambient Pressure ◽  
Low Carbon ◽  
Electrocatalytic Hydrogenation ◽  
Faradaic Efficiency ◽  
Renewable Chemicals ◽  
Oxygenated Hydrocarbons ◽  
Bio Oil ◽  
Partial Current

Abstract Catalytic hydrogenation of bio-oil provides an avenue to produce renewable chemicals. To this end, electrocatalytic hydrogenation is especially interesting when powered using low-carbon electricity; however, it has to date lacked the needed selectivity: when hydrogenating bio-oil to oxygenated hydrocarbons, for example, it reduces the desired oxygenated groups (-OH and -OCH3). Here we report that Rh and Au modulate electronic structure of Pt and steer intermediate energetics to favor the hydrogenation while suppressing deoxygenation using computational studies and in-situ spectroscopies. PtRhAu catalysts achieve a record 47% faradaic efficiency (FE) and a partial current density (Jp) of 28 mA·cm-2 toward oxygenated 2-methoxycyclohexanol from lignin-derived guaiacol under room temperature and ambient pressure, representing 1.5x FE and 3.5x Jp increases compared to the best prior reports. We further demonstrate an integrated lignin biorefinery where wood-derived lignin oils are selectively hydrogenated and funneled to the oxygenated 2-methoxy-4-propylcyclohexanol using PtRhAu catalysts.

scholarly journals A New in-situ Exsolution Supporting Framework for Metal Nanoparticle Growth

2021 ◽  
Author(s):  
Mengchu Wang ◽  
Bike Zhang ◽  
Jiaqi Ding ◽  
Fanxing Zhang ◽  
Rui Tu ◽  
...  
Keyword(s):  
Metal Nanoparticles ◽  
High Stability ◽  
Room Temperature ◽  
Design Principle ◽  
Metal Nanoparticle ◽  
Uniform Size ◽  
Faradaic Efficiency ◽  
Nanoparticle Growth ◽  
Catalytic Materials

Abstract Catalysts made of in-situ exsolved metal nanoparticles often demonstrate promising activity and high stability in many applications. However, the design of these catalysts is greatly constrained by the classic exsolution mechanism, which occurs almost exclusively through substitutional metal-doping in perovskites. Here we show that metal nanoparticles can also be in-situ exsolved from interstitially doped metal cations in a NiOOH supporting framework with the guidance of theoretical calculation. The exsolution can be conducted swiftly at room temperature. A novel copper nanocatalyst prepared with this approach have a quasi-uniform size of 4 nm delivering an exceptional CO faradaic efficiency of 95.6% with a notable durability for the electrochemical reduction of CO2. This design principle is further proven to be generally applicable to other metals and foregrounded for guiding the development of advanced catalytic materials.

scholarly journals Room-Temperature Reaction of Oxygen with Gold: An In situ Ambient-Pressure X-ray Photoelectron Spectroscopy Investigation

2010 ◽  
Vol 132 (9) ◽  
pp. 2858-2859 ◽  
Author(s):  
Peng Jiang ◽  
Soeren Porsgaard ◽  
Ferenc Borondics ◽  
Mariana Köber ◽  
Alfonso Caballero ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Ambient Pressure ◽  
Temperature Reaction ◽  
X Ray

scholarly journals Single-pass flow-through reaction cell for high-temperature and high-pressurein situneutron diffraction studies of hydrothermal crystallization processes

2012 ◽  
Vol 45 (2) ◽  
pp. 166-173 ◽  
Author(s):  
Fang Xia ◽  
Joël Brugger ◽  
Gujie Qian ◽  
Yung Ngothai ◽  
Brian O'Neill ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Flow Rate ◽  
Room Temperature ◽  
Ambient Pressure ◽  
Vacuum Furnace ◽  
Hydrothermal Crystallization ◽  
Single Pass ◽  
Flow Through

A large-volume single-pass flow-through cell forin situneutron diffraction investigation of hydrothermal crystallization processes is reported. The cell is much more versatile than previous designs owing to the ability to control independently and precisely temperature (up to 673 K), pressure (up to 46 MPa), flow rate (0.01–10 ml min−1) and reaction-fluid volume (≥65 ml). Such versatility is realized by an innovative design consisting of a room-temperature and ambient-pressure external fluid supply module, a high-pressure reaction module which includes a high-temperature sample compartment enclosed in a vacuum furnace, and a room-temperature and high-pressure backpressure regulation module for pressure control. The cell provides a new avenue for studying various parameters of hydrothermal crystallizations independently,in situand in real time at extreme hydrothermal conditions (e.g.supercritical). The cell was successfully commissioned on the high-intensity powder diffractometer beamline, Wombat, at the Australian Nuclear Science and Technology Organisation by investigating the effect of pressure on the hydrothermal pseudomorphic conversion from SrSO4(celestine) to SrCO3(strontianite) at a constant temperature of 473 K and flow rate of 5 ml min−1. The results show that the increase of pressure exerts a nonlinear effect on the conversion rate, which first increases with increasing pressure from 14 to 20 MPa, and then decreases when pressure further increases to 24 MPa.

scholarly journals Highly efficient ethylene production via electrocatalytic hydrogenation of acetylene under mild conditions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Suheng Wang ◽  
Kelechi Uwakwe ◽  
Liang Yu ◽  
Jinyu Ye ◽  
Yuezhou Zhu ◽  
...  
Keyword(s):  
Ethylene Production ◽  
High Efficiency ◽  
Ambient Pressure ◽  
Industrial Process ◽  
Electrocatalytic Hydrogenation ◽  
Hydrogen Electrode ◽  
Faradaic Efficiency ◽  
Mild Conditions ◽  
Highly Efficient ◽  
Cu Catalyst

AbstractRenewable energy-based electrocatalytic hydrogenation of acetylene to ethylene (E-HAE) under mild conditions is an attractive substitution to the conventional energy-intensive industrial process, but is challenging due to its low Faradaic efficiency caused by competitive hydrogen evolution reaction. Herein, we report a highly efficient and selective E-HAE process at room temperature and ambient pressure over the Cu catalyst. A high Faradaic efficiency of 83.2% for ethylene with a current density of 29 mA cm−2 is reached at −0.6 V vs. the reversible hydrogen electrode. In-situ spectroscopic characterizations combined with first-principles calculations reveal that electron transfer from the Cu surface to adsorbed acetylene induces preferential adsorption and hydrogenation of the acetylene over hydrogen formation, thus enabling a highly selective E-HAE process through the electron-coupled proton transfer mechanism. This work presents a feasible route for high-efficiency ethylene production from E-HAE.

In situ XRPD study of the ambient-pressure synthesis of nonstoichiometric Ag3O from Ag–Ag2O thin films: Phase abundance, unit-cell parameters, and c/a as a function of temperature and time

2020 ◽  
Vol 35 (4) ◽  
pp. 247-261
Author(s):  
Paul J. Schields ◽  
Nicholas Dunwoody ◽  
David Field ◽  
Zachary Wilson
Keyword(s):  
Thin Films ◽  
Cell Volume ◽  
Room Temperature ◽  
Unit Cell Volume ◽  
Ambient Pressure ◽  
Thermal Reaction ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Cell Parameters

Ag3O was synthesized by jet-milling magnetron-sputtered Ag–Ag2O thin films. Heating the jet-milled powders in air and N2 from 40 to 148 °C at ambient pressure produced Ag3O-rich powders. The phase composition and unit-cell parameters of the jet-milled powders were measured as a function of temperature with in situ X-ray powder diffraction experiments from −186 to 293 °C. Ag3O was also produced by ball milling and sonicating jet-milled films at ambient conditions. The phase composition, unit-cell parameters, and thermal-reaction rates indicate nonstoichiometric Ag3O was produced from the reaction of metastable, nonstoichiometric Ag2O (cuprite structure) and ccp Ag. The thermal expansion of Ag3O is anisotropic; below 25 °C, the a-axis expansion is about twice the c-axis expansion resulting in a negative slope of c/a(T). The reversal of the sign of c/a(T) near 25 °C is dramatic. The thermal reaction is arrested when the temperature is rapidly increased from ambient to 130 °C. Ag3O is metastable and decreases its unit-cell volume during kinetic decomposition to Ag when heated above ambient temperature in air and nitrogen. The relative volume expansion of Ag3O is about 80% less than Ag at room temperature and below. The suite of nonstoichiometric Ag3O produced by heating displays a linear relation between c/a and unit-cell volume at room temperature. The c/a and unit-cell volume of a hydrothermally grown Ag3O single crystal reported in a published structure determination was the Ag-rich, low-volume end member of the linear series. The c/a and unit-cell volume are sensitive indicators of the oxygen content and state of disorder.

Thermomechanical Treatment of a 4340 Ni-Cr-Mo Alloy Steel

1981 ◽  
Vol 39 ◽  
pp. 314-315 ◽  
Author(s):  
M.T. Jahn ◽  
J.C. Yang ◽  
C.M. Wan
Keyword(s):  
Mechanical Property ◽  
Chemical Composition ◽  
Alloy Steel ◽  
Thermomechanical Treatment ◽  
Room Temperature ◽  
Good Combination ◽  
Thermal Treatments ◽  
Low Carbon ◽  
4340 Steel ◽  
Good Improvement

4340 Ni-Cr-Mo alloy steel is widely used due to its good combination of strength and toughness. The mechanical property of 4340 steel can be improved by various thermal treatments. The influence of thermomechanical treatment (TMT) has been studied in a low carbon Ni-Cr-Mo steel having chemical composition closed to 4340 steel. TMT of 4340 steel is rarely examined up to now. In this study we obtain good improvement on the mechanical property of 4340 steel by TMT. The mechanism is explained in terms of TEM microstructures4340 (0.39C-1.81Ni-0.93Cr-0.26Mo) steel was austenitized at 950°C for 30 minutes. The TMTed specimen (T) was obtained by forging the specimen continuously as the temperature of the specimen was decreasing from 950°C to 600°C followed by oil quenching to room temperature. The thickness reduction ratio by forging is 40%. The conventional specimen (C) was obtained by quenching the specimen directly into room temperature oil after austenitized at 950°C for 30 minutes. All quenched specimens (T and C) were then tempered at 450, 500, 550, 600 or 650°C for four hours respectively.

Otoconia perfect/imperfect crystals

1994 ◽  
Vol 52 ◽  
pp. 42-43
Author(s):  
César D. Fermin ◽  
Dale Martin
Keyword(s):  
Image Processing ◽  
Room Temperature ◽  
Phosphotungstic Acid ◽  
Gallus Domesticus ◽  
Crystal Matrix ◽  
Organic Templates ◽  
Image Processing Algorithms ◽  
Processing Algorithms ◽  
Diffraction Patterns

Otoconia of higher vertebrates are interesting biological crystals that display the diffraction patterns of perfect crystals (e.g., calcite for birds and mammal) when intact, but fail to produce a regular crystallographic pattern when fixed. Image processing of the fixed crystal matrix, which resembles the organic templates of teeth and bone, failed to clarify a paradox of biomineralization described by Mann. Recently, we suggested that inner ear otoconia crystals contain growth plates that run in different directions, and that the arrangement of the plates may contribute to the turning angles seen at the hexagonal faces of the crystals.Using image processing algorithms described earlier, and Fourier Transform function (2FFT) of BioScan Optimas®, we evaluated the patterns in the packing of the otoconia fibrils of newly hatched chicks (Gallus domesticus) inner ears. Animals were fixed in situ by perfusion of 1% phosphotungstic acid (PTA) at room temperature through the left ventricle, after intraperitoneal Nembutal (35mg/Kg) deep anesthesia. Negatives were made with a Hitachi H-7100 TEM at 50K-400K magnifications. The negatives were then placed on a light box, where images were filtered and transferred to a 35 mm camera as described.

In Situ Localization of PPAR Gamma and Uncoupling Protein in Mouse Embryo Sections Using Digoxigenin-Labeled Riboprobes

1996 ◽  
Vol 54 ◽  
pp. 32-33
Author(s):  
C. Jennermann ◽  
S. A. Kliewer ◽  
D. C. Morris
Keyword(s):  
Alkaline Phosphatase ◽  
Room Temperature ◽  
Uncoupling Protein ◽  
Ppar Gamma ◽  
Nuclear Hormone Receptor ◽  
Full Length ◽  
Northern Analysis ◽  
Peroxisome Proliferator

Peroxisome proliferator-activated receptor gamma (PPARg) is a member of the nuclear hormone receptor superfamily and has been shown in vitro to regulate genes involved in lipid metabolism and adipocyte differentiation. By Northern analysis, we and other researchers have shown that expression of this receptor predominates in adipose tissue in adult mice, and appears first in whole-embryo mRNA at 13.5 days postconception. In situ hybridization was used to find out in which developing tissues PPARg is specifically expressed.Digoxigenin-labeled riboprobes were generated using the Genius™ 4 RNA Labeling Kit from Boehringer Mannheim. Full length PPAR gamma, obtained by PCR from mouse liver cDNA, was inserted into pBluescript SK and used as template for the transcription reaction. Probes of average size 200 base pairs were made by partial alkaline hydrolysis of the full length transcripts. The in situ hybridization assays were performed as described previously with some modifications. Frozen sections (10 μm thick) of day 18 mouse embryos were cut, fixed with 4% paraformaldehyde and acetylated with 0.25% acetic anhydride in 1.0M triethanolamine buffer. The sections were incubated for 2 hours at room temperature in pre-hybridization buffer, and were then hybridized with a probe concentration of 200μg per ml at 70° C, overnight in a humidified chamber. Following stringent washes in SSC buffers, the immunological detection steps were performed at room temperature. The alkaline phosphatase labeled, anti-digoxigenin antibody and detection buffers were purchased from Boehringer Mannheim. The sections were treated with a blocking buffer for one hour and incubated with antibody solution at a 1:5000 dilution for 2 hours, both at room temperature. Colored precipitate was formed by exposure to the alkaline phosphatase substrate nitrobluetetrazoliumchloride/ bromo-chloroindlylphosphate.

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