Coalescence and shape oscillations of Au nanoparticles in CO2 hydrogenation for methanol reaction

Nanoscale ◽  
2021 ◽  
Author(s):  
Shengnan Yue ◽  
Yongli Shen ◽  
Ziliang Deng ◽  
Wenjuan Yuan ◽  
Wei Xi
Keyword(s):  
Au Nanoparticles ◽  
High Selectivity ◽  
Co2 Hydrogenation ◽  
Au Nanoparticle ◽  
Limited Knowledge ◽  
Shape Oscillations

Recently, there has been renewed interest in Au nanoparticle (Au NP) catalysts owing to their high selectivity for CO2 hydrogenation to methanol. However, there is still limited knowledge on the...

scholarly journals Highly Selective Au/ZnO via Colloidal Deposition for CO2 Hydrogenation to Methanol: Evidence of AuZn Role

2021 ◽  
Vol 16 (1) ◽  
pp. 44-51
Author(s):  
Hasliza Bahruji ◽  
Mshaal Almalki ◽  
Norli Abdullah
Keyword(s):  
Active Sites ◽  
Au Nanoparticles ◽  
High Selectivity ◽  
Average Diameter ◽  
Co2 Hydrogenation ◽  
Impregnation Method ◽  
Co2 Conversion ◽  
Methanol Production ◽  
Surface Oxygen Vacancy ◽  
Colloidal Method

Gold, Au nanoparticles were deposited on ZnO, Al2O3, and Ga2O3 via colloidal method in order to investigate the role of support for CO2 hydrogenation to methanol. Au/ZnO was also produced using impregnation method to investigate the effect of colloidal method to improve methanol selectivity. Au/ZnO produced via sol immobilization showed high selectivity towards methanol meanwhile impregnation method produced Au/ZnO catalyst with high selectivity towards CO. The CO2 conversion was also influenced by the amount of Au weight loading. Au nanoparticles with average diameter of 3.5 nm exhibited 4% of CO2 conversion with 72% of methanol selectivity at 250 °C and 20 bar. The formation of AuZn alloy was identified as active sites for selective CO2 hydrogenation to methanol. Segregation of Zn from ZnO to form AuZn alloy increased the number of surface oxygen vacancy for CO2 adsorption to form formate intermediates. The formate was stabilized on AuZn alloy for further hydrogenation to form methanol.  The use of Al2O3 and Ga2O3 inhibited the formation of Au alloy, and therefore reduced methanol production. Au/Al2O3 showed 77% selectivity to methane, meanwhile Au/Ga2O3 produced 100% selectivity towards CO. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

MOF Encapsulated Sub-nm Pd skin/Au Nanoparticles as Antenna-Reactor Plasmonic Catalyst for Light Driven CO2 Hydrogenation

Nano Energy ◽  
2021 ◽  
pp. 105950
Author(s):  
Xibo Zhang ◽  
Yunyan Fan ◽  
Enming You ◽  
Zexuan Li ◽  
Yongdi Dong ◽  
...  
Keyword(s):  
Au Nanoparticles ◽  
Co2 Hydrogenation

scholarly journals Electroless Deposited Gold Nanoparticles on Glass Plates as Sensors for Measuring the Dielectric Constant of Solutions

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Y. Kobayashi ◽  
Y. Ishii
Keyword(s):  
Dielectric Constant ◽  
Au Nanoparticles ◽  
Glass Plate ◽  
Au Nanoparticle ◽  
Peak Wavelength ◽  
Nanoparticle Deposition ◽  
Metal Plating ◽  
Large Dielectric Constant ◽  
Electroless Metal Plating ◽  
Glass Plates

This work describes a method for the deposition of Au nanoparticles on glass plates (Au-glass). An electroless metal plating technique was extended to the Au nanoparticle deposition. The technique consisted of three steps that took place on the glass plate: (1) adsorption of Sn2+ ions, (2) deposition of metallic Ag nuclei generated by reducing Ag+ ions with Sn2+ ions on the Sn-adsorbed sites, and (3) deposition of Au nanoparticles by reducing Au+ ions on the Ag surface. TEM observation revealed that metallic Au nanoparticles with a size of  nm were formed on the glass surface. A surface plasmon resonance absorption peak was observed, and its peak wavelength redshifted by immersing the Au-glass into a solution with a large dielectric constant. The redshift corresponded qualitatively to the calculation by the Mie theory accompanying the Drude expression, which was based on the change of the dielectric constant of the solution. The obtained results indicated that the Au-glass functioned as a sensor for measuring the dielectric constant of the solution.

scholarly journals Effect of Conditions of Sol-Gel Synthesis and Post-Synthetic Treatment on Photoelectrochemical and Electro-Catalytic Properties of Titanium Oxide Nanostructures and Tio2-Au Nanocomposites

2021 ◽  
Vol 57 (4) ◽  
pp. 1-14
Author(s):  
N.I. Romanovska ◽  
◽  
P.A. Manorik ◽  
V.S. Vorobets ◽  
G.Ya. Kolbasov ◽  
...  
Keyword(s):  
Visible Light ◽  
Au Nanoparticles ◽  
Sol Gel ◽  
Au Nanoparticle ◽  
Chemical Compositions ◽  
High Catalytic Activity ◽  
Electron Microscopies ◽  
Treatment Conditions ◽  
Carboxylate Groups ◽  
Tio2 Nanostructures

Carbon-doped mesoporous TiO2 nanostructures and TiO2-Au nanocomposites with stabilized Au nanoparticles have been synthesized by the sol-gel template method and characterized by X-ray diffraction, scanning and transmission electron microscopies, Fourier-transform infrared spectroscopy, N2 adsorption/desorption, ultraviolet-visible spectroscopy, and photoelectrochemical current spectroscopy. The synthesis hydrothermal treatment conditions affected the particle size, electronic structure, morphology, phase, and chemical compositions, as well as the texture of the synthesized materials. The TiO2 and TiO2-Au based electrodes were light-sensitive in a wavelength range of 250–412 nm and were distinguished by a high catalytic activity during oxygen electroreduction. The presence of -ol and carboxylate groups in the amorphous phase is the main factor affecting the photosensitivity of TiO2 nanostructures to visible light and an increase in their photoactivity during the decomposition of methylene blue upon irradiation with ultraviolet and visible light relative to pure anatase. The higher photosensitivity and photoactivity of TiO2-Au nanocomposites compared with those of the corresponding starting TiO2 is due to the synergistic effect of Au nanoparticles and interstitial Ti-O-C groups, which depends on the Au nanoparticle content of the composite and on the mesopore size.

scholarly journals Thermal atomic layer deposition of gold nanoparticles: controlled growth and size selection for photocatalysis

Nanoscale ◽  
2020 ◽  
Vol 12 (16) ◽  
pp. 9005-9013 ◽  
Author(s):  
Fatemeh S. M. Hashemi ◽  
Fabio Grillo ◽  
Vikram R. Ravikumar ◽  
Dominik Benz ◽  
Ankit Shekhar ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Atomic Layer Deposition ◽  
Fluidized Bed ◽  
Au Nanoparticles ◽  
Atomic Layer ◽  
Fluidized Bed Reactor ◽  
Au Nanoparticle ◽  
Pulse Time ◽  
Layer Deposition ◽  
Selection For

Thermal atomic layer deposition of Au nanoparticles on titania in a fluidized bed reactor. Effects of precursor pulse time on Au nanoparticle size and loading.

Noble metal nanoparticle-decorated TiO2 nanobelts for enhanced photocatalysis

2014 ◽  
Vol 07 (05) ◽  
pp. 1450064 ◽  
Author(s):  
Haiyan He ◽  
Ping Yang ◽  
Changchao Jia ◽  
Yanping Miao ◽  
Jie Zhao ◽  
...  
Keyword(s):  
Noble Metal ◽  
Au Nanoparticles ◽  
Acid Corrosion ◽  
Metal Nanoparticle ◽  
Noble Metal Nanoparticles ◽  
Au Nanoparticle ◽  
Chloroauric Acid ◽  
Sem Images ◽  
Photogenerated Electrons ◽  
Coarse Surface

TiO 2 nanobelts have been fabricated through a hydrothermal method and subsequently sulfuric-acid-corrosion-treated for a rough surface. Noble metal nanoparticles such as Ag and Au were deposited on the coarse surface of TiO 2 nanobelts via a coprecipitation procedure. Ag – TiO 2 nanobelts were prepared in ethanolic solution contained silver nitrate ( AgNO 3) and sodium hydroxide ( NaOH ). Au – TiO 2 nanobelts were obtained in chloroauric acid ( HAuCl 4) using sodium borohydride ( NaBH 4) as the reductant. It is confirmed by the results of XRD patterns together with the SEM images that the composite of noble metal and TiO 2 nanobelts were obtained successfully and the Ag or Au nanoparticles were well-dispersed on the TiO 2 nanobelts. Moreover, the as-prepared Ag and Au nanoparticle-decorated TiO 2 nanobelts represent an enhanced photocatalytic activity compared with pure TiO 2 nanobelts, which is due to the fact that the Ag and Au nanoparticles on the surface of TiO 2 nanobelts act as sinks for the photogenerated electrons and promote the separation of the electrons and holes.

Microstructure and Optical Properties of Au–Y2O3-stabilized ZrO2 Nanocomposite Films

2005 ◽  
Vol 20 (9) ◽  
pp. 2516-2522 ◽  
Author(s):  
George Sirinakis ◽  
Rezina Siddique ◽  
Christos Monokroussos ◽  
Michael A. Carpenter ◽  
Alain E. Kaloyeros
Keyword(s):  
Optical Properties ◽  
Au Nanoparticles ◽  
Annealing Temperature ◽  
Rutherford Backscattering Spectrometry ◽  
Nanocomposite Films ◽  
Au Nanoparticle ◽  
X Ray Diffraction ◽  
Working Pressure ◽  
Optical Absorption Band ◽  
Size Dependent

Nanocomposite films consisting of gold nanoparticles embedded in an yttria stabilized zirconia (YSZ) matrix were synthesized at room temperature by radio-frequency co-sputtering from YSZ and Au targets at a 5 mTorr working pressure. The films were subsequently annealed for 2 h in 1 atm argon, with the annealing temperature varied from 600 to 1000 °C in steps of 100 °C. The composition, microstructure, and optical properties of the films were characterized as a function of annealing temperature by Rutherford backscattering spectrometry, scanning electron microscopy, Auger electron spectroscopy, x-ray diffraction, and absorption spectroscopy. An optical absorption band due to the surface plasmon resonance (SPR) of the Au nanoparticles was observed around a wavelength of 600 nm. Furthermore, the SPR band full width at half-maximum exhibited an inverse linear dependence on the radius of the Au nanoparticle, with a slope parameter A = 0.18, indicating a weak interaction between the YSZ matrix and the Au nanoparticles. The experimentally observed SPR dependence on nanoparticle size is discussed within the context of the Mie theory and its size-dependent optical constants.

scholarly journals High selectivity of CO2 hydrogenation to CO by controlling the valence state of nickel using perovskite

2018 ◽  
Vol 54 (53) ◽  
pp. 7354-7357 ◽  
Author(s):  
Baohuai Zhao ◽  
Binhang Yan ◽  
Zhao Jiang ◽  
Siyu Yao ◽  
Zongyuan Liu ◽  
...  
Keyword(s):  
Valence State ◽  
High Selectivity ◽  
Co2 Hydrogenation ◽  
Product Selectivity

The product selectivity of CO2 hydrogenation can be significantly tuned by controlling the valence state of Ni using perovskites.

scholarly journals Highly Responsive and Ultrasensitive Non-Enzymatic Electrochemical Glucose Sensor Based on Au Foam

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1203 ◽  
Author(s):  
Nannan Shen ◽  
Haijun Xu ◽  
Weichen Zhao ◽  
Yongmei Zhao ◽  
Xin Zhang
Keyword(s):  
High Selectivity ◽  
Glucose Sensor ◽  
Limit Of Detection ◽  
Surface Enhanced Raman Spectroscopy ◽  
Au Nanoparticle ◽  
Quantitative Detection ◽  
Term Stability ◽  
Long Term Stability ◽  
Surface Enhanced Raman

Glucose concentration is an important physiological index, therefore methods for sensitive detection of glucose are important. In this study, Au foam was prepared by electrodeposition with a dynamic gas template on an Au nanoparticle/Si substrate. The Au foam showed ultrasensitivity, high selectivity, and long-term stability in the quantitative detection of glucose. The foam was used as an electrode, and the amperometric response indicated excellent catalytic activity in glucose oxidation, with a linear response across the concentration range 0.5 μM to 12 mM, and a limit of detection of 0.14 μM. High selectivity for interfering molecules at six times the normal level and long-term stability for 30 days were obtained. The results for electrochemical detection with Au foam of glucose in human serum were consistent with those obtained with a sensor based on surface-enhanced Raman spectroscopy and a commercial sensor. This proves that this method can be used with real samples. These results show that Au foam has great potential for use as a non-enzymatic glucose sensor.

Hydrogen Peroxide Sensor Based on Horseradish Peroxide (HRP) Immobilized PANI Electrode with Au Nanoparticles

2007 ◽  
Vol 342-343 ◽  
pp. 865-868 ◽  
Author(s):  
Kang Deuk Seo ◽  
Seong Dae Oh ◽  
Seong Ho Choi ◽  
Sang Hyub Oh ◽  
Jin Chun Woo ◽  
...  
Keyword(s):  
Au Nanoparticles ◽  
Electrochemical Polymerization ◽  
Physical Adsorption ◽  
Covalent Bonding ◽  
Au Nanoparticle ◽  
Adsorption Method ◽  
Au Film ◽  
Self Assembling ◽  
Horseradish Peroxide ◽  
Immobilization Method

In order to prepare the enzyme electrode for sensing of chemical molecules, the Au was coated on the surface of PP film by sputter coater. Polyaniline (PANI) was polymerized on the surface of the coated Au film by electrochemical polymerization of aniline in order to use working electrode. Subsequently, horseradish peroxide (HRP) was immobilized on PANI electrode as follows: Method I. The HRP was immobilized on the surface of PANI electrode by using Au nanoparticle as linker (physical adsorption). Method II. The HRP was immobilized on the surface of PANI electrode by using 2-aminothiophenol and Au nanoparticle as linker (Self-assembling immobilization). Method III. HRP was directly immobilized with PANI electrode by using glutaric dialdehyde as linker (covalent bonding). The sensing efficiency of the prepared HRP-PANI electrode was also examined. The sensing efficiency of the HRP-PANI electrode for H2O2 was as following order; Method I > Method III > Method II..

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