CuO nanorods were synthesized by hydrothermal methods with three different chemical combinations: (i) copper nitrate, lactic acid, and sodium hydroxide; (ii) copper sulfate, sodium lactate, and sodium hydroxide; and (iii) copper nitrate and sodium hydroxide. Physical parameters, concentration, temperature, and aging time, greatly affected the size and morphology of the nanorods; CuO nanoparticles were also prepared. These nanorods and nanoparticles were reduced to metallic copper at elevated temperature by 4% H2 diluted in helium. The morphology of CuO nanomaterials (nanorods and nanoparticles) was preserved after reduction. These CuO and Cu nanorods and nanoparticles were characterized by XRD, SEM, TEM, SEM-EDS, and BET measurements. The CuO and Cu nanomaterials were employed for near-infrared (NIR) diffuse reflectance. Among these materials, CuO nanorods were to be found the best NIR diffuse reflectors, indicating potential application as NIR obscurants.

Synthesis of CuO Nanorods, Reduction of CuO into Cu Nanorods, and Diffuse Reflectance Measurements of CuO and Cu Nanomaterials in the Near Infrared Region

Chemical-looping combustion (CLC) has the inherent property of separating CO2 from flue gases. Instead of air, it uses an oxygen-carrier, usually in the form of a metal oxide, to provide oxygen for combustion. When used for the combustion of gaseous fuels, such as natural gas, or synthesis gas from the gasification of coal, the technique gives a stream of CO2 which, on an industrial scale, would be sufficiently pure for geological sequestration. An important issue is the form of the metal oxide, since it must retain its reactivity through many cycles of complete reduction and oxidation. Here, we report on the rates of oxidation of one constituent of synthesis gas, H2, by co-precipitated mixtures of CuO+Al2O3 using a laboratory-scale fluidised bed. To minimise the influence of external mass transfer, and also of errors in the measurement of [H2], particles sized to 355-500μm were used at low [H2], with the temperature ranging from 450 to 900°C. Under such conditions, the reaction was slow enough for meaningful measurements of the intrinsic kinetics to be made. The reaction was found to be first order with respect to H2. Above ∼800°C, the reaction of CuO was fast and conformed to the shrinking core mechanism, proceeding via the intermediate, Cu2O, in: 2CuO+H2→Cu2O+H2O, ΔH1073 K0=- 116.8 kJ/mol; Cu2O+H2→2Cu+H2O, ΔH1073 K0-80.9 kJ/mol. After oxidation of the products Cu and Cu2O back to CuO, the kinetics in subsequent cycles of chemical looping oxidation of H2 could be approximated by those in the first. Interestingly, the carrier was found to react at temperatures as low as 300°C. The influence of the number of cycles of reduction and oxidation is explored. Comparisons are drawn with previous work using reduction by CO. Finally, these results indicate that the kinetics of reaction of the oxygen carrier with gasifier synthesis gases is very much faster than rates of gasification of the original fuel. © 2010 The Institution of Chemical Engineers.

Kinetics of the chemical looping oxidation of CO by a co-precipitated mixture of CuO and Al2O3

Metals Production and Metal Oxides Reduction Using Hydrogen: A Review

The adsorption of H2 on the Cu2O(111) surface has been studied by spin-polarized density functional theory (DFT+U) calculations and atomic thermodynamics. It has been found that there exists reconstruction on a stoichiometric Cu2O(111) surface. The probability distribution of the reconstructed Cu2O(111) surfaces as a function of temperature has been analyzed using Boltzmann statistics. It has been found that the molecular H2 prefers to adsorption on the uncoordinated CuCUS atom at low coverages (1/4 or 1/2 monolayer), while totally dissociative H2 is preferred on the reconstructed Cu2O(111) surface at higher coverages (3/4 or 1 monolayer). For H2 splitting on the Cu2O(111) surface, homolytical dissociative adsorption on two surface-uncoordinated CuCUS atoms is preferred which is a new mechanism for H2 on metal oxides. More interesting is that the surface reconstruction will be recovered for eight hydrogen atoms binding on four uncoordinated CuCUS and four uncoordinated OCUS atoms at saturation coverage. I...

High-Coverage H2 Adsorption on the Reconstructed Cu2O(111) Surface

Structural and surface features of highly dispersed copper catalysts supported on hierarchical porous alumina were evaluated for the ethanol dehydrogenation reaction. The catalysts were prepared by incipient wetness impregnation of alumina obtained by a dual template sol–gel procedure. Structural characterizations provided evidence that the copper was highly dispersed on the alumina in the form of monomeric octahedral Cu2+ species adsorbed into an incomplete layer. A two-step reduction was observed for the catalysts in a temperature range of 50–250 °C under H2/He flow. The temperature for onset of reduction and the percentage of Cu+ species formed upon activation were dependent on the Cu loading. At lower Cu loadings, the amount of Cu+ increased, leading to a slower and less complete reduction. Based on the apparent activation energy and turnover frequency, it could be concluded that Cu+ containing a mixture of Cu+/Cu0 results in a more efficient catalyst than Cu0 for the ethanol dehydrogenation reaction.

Correlation between Structural and Catalytic Properties of Copper Supported on Porous Alumina for the Ethanol Dehydrogenation Reaction

CuO and Cu 2 O powders were reacted by hydrogen to study the reduction mechanism and the ionic states of Cu (Cu 2+ , Cu 1+ and Cu 0 ). The reduction behaviour and the existence of an intermediate state were investigated by using synchrotron-based high-resolution in situ x-ray diffraction (S-XRD) techniques. The results revealed that CuO directly reduces to metallic Cu (Cu 2+ > Cu 0 ), under a normal flow of hydrogen. There was no hint of an intermediate state (Cu 1+ ) during the reduction. In certain conditions, however, an intermediate phase (Cu 2 O) appears under either very small flow of hydrogen ( 20 °C min -1 ), suggesting that the reduction kinetics strongly depends on reduction conditions.

Reaction of CuO with hydrogen studied by using synchrotron-based x-ray diffraction

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Jae Y Kim

Author Tools

Chat about Author

Papers

Reaction of CuO with hydrogen studied by using synchrotron-based x-ray diffraction