Synthesis and Characterization of Cu Nanoparticles

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Questions and Answers

What does the photocatalytic mechanism primarily consist of?

Heat generation and light absorption.

Surface tension and photon interaction.

Photo and catalysis. (correct)

Chemical reaction and temperature change.

What is the first part of the photocatalytic mechanism focused on?

Surface radical formation.

Photon absorption and charge creation. (correct)

Temperature regulation.

Organic pollutant degradation.

Which of the following contributes to surface reactivity in the photocatalytic process?

Wavelength absorption.

Temperature fluctuations.

Photon dynamics.

Surface radical formation. (correct)

In the context of photocatalysis, which wavelengths would likely be most effective for photon absorption based on the given graph?

500-600 nm. Signup and view all the answers

What are the main atmospheric components correlated with the surface radical formation during photocatalysis?

H2O, O2, and organic pollutants. Signup and view all the answers

At what time interval does the observed absorbance in the graph show a steady increase?

30 to 90 minutes. Signup and view all the answers

What does a steady absorbance reading in the context of photocatalysis indicate?

Stable charge creation dynamics. Signup and view all the answers

Why is the wavelength range of 500-800 nm significant in photocatalytic activity?

It is associated with effective photon interaction. Signup and view all the answers

What structural change in collagen is observed with increased exposure time?

Denaturation to a mixture of random-coil strands Signup and view all the answers

At what wavelength did the absorption peaks corresponding to methylene blue (MB) disappear?

664 nm Signup and view all the answers

What interaction occurs between fish scale extract and copper sulfate solution?

Instantaneous complex formation due to electrostatic interaction Signup and view all the answers

What was the result of the control experiment with the dye solution under sunlight without NPs?

Negligible degradation of the dye was observed Signup and view all the answers

What type of reaction describes the rate of degradation of dyes in the presence of NPs?

Pseudo-first-order reaction Signup and view all the answers

What percentage of degradation of MB was achieved by the synthesized Cu NPs?

96% Signup and view all the answers

Which of the following is NOT a product of collagen denaturation?

Triple helix structures Signup and view all the answers

What is a possible mechanism for the formation of Cu NPs as described in the content?

Autocatalytic pathway Signup and view all the answers

What was the average size of the synthesized Cu nanoparticles (NPs) as observed from the TEM and HRTEM studies?

31 ± 6 nm Signup and view all the answers

Which wavelength of radiation was used in the XRD pattern recording?

1.5418 A0 Signup and view all the answers

What does the fringe spacing of 0.21 nm correspond to in the context of HRTEM results?

(111) plane of fcc Cu NPs Signup and view all the answers

What method was used to evaluate the photocatalytic activity of the synthesized Cu NPs?

UV-visible spectroscopy Signup and view all the answers

How long was the suspended solution of Cu nanoparticles allowed to stand in the dark to reach adsorption–desorption equilibrium?

1 hour Signup and view all the answers

What does the SAED pattern display in relation to the synthesized Cu NPs?

Diffraction rings corresponding to (111), (200), (220), and (311) planes Signup and view all the answers

What was the reducing and stabilizing agent used for synthesizing Cu NPs?

Fish scale extract of L. rohita Signup and view all the answers

What atmospheric conditions were encountered during the photocatalytic activity experiments?

32–36 °C Signup and view all the answers

What does the slope of the plot of ln (C0/Ct) vs irradiation time t represent?

The pseudo-first-order rate constant (k) Signup and view all the answers

Which of the following components is involved in the creation of self-assembled Cu NPs?

CuSO4.5H2O and gelatin Signup and view all the answers

What is the assumed role of the self-assembled Cu NPs in the context provided?

To act as a catalyst for dye removal Signup and view all the answers

During the synthesis of Cu NPs, what is the temperature at which heating and stirring occur?

100°C Signup and view all the answers

What does 'Ct' represent in the equation ln C0 Ct = kt?

Concentration of dye at time t Signup and view all the answers

What outcome can be inferred from the linear relationship in the plot of ln (C0/Ct) vs time?

The reaction is first-order with respect to dye concentration. Signup and view all the answers

What weight percentage of copper is shown in the composition of the synthesized Cu NPs?

100% Signup and view all the answers

Which parameter is NOT mentioned as part of the formation mechanism of Cu NPs?

Cooling Signup and view all the answers

What initiates the direct electron injection into the adsorbate?

Interaction between adsorbate and excited surface plasmons Signup and view all the answers

Which species is generated by the protonation of the superoxide ion?

Hydroperoxyl radical (HO2.) Signup and view all the answers

What is the final product of hydrogen peroxide dissociation?

Hydroxyl radical (OH.) Signup and view all the answers

What dual processes occur on the surface of the photocatalyst?

Oxidation and reduction Signup and view all the answers

Which radicals are produced by the reaction of electrons and holes with O2 and H2O?

Anionic superoxide radical (O2−.) and hydroxyl radical (OH.) Signup and view all the answers

What role do excited surface plasmons play in the process described?

They facilitate the direct injection of electrons Signup and view all the answers

What is the first radical formed in the sequence described?

Anionic superoxide radical (O2−.) Signup and view all the answers

Which statement best describes the process of electron injection into the adsorbate?

It is a consequence of electron and hole generation due to plasmonic decay. Signup and view all the answers

Study Notes

Photocatalytic Mechanism

The photocatalytic mechanism primarily involves the absorption of photons to generate electron-hole pairs in the photocatalyst.
The first part focuses on the absorption of photons and the generation of electron-hole pairs.
Surface reactivity is influenced by the creation of reactive oxygen species (ROS) during photocatalysis.

Wavelengths and Atmospheric Components

Wavelengths in the UV range are most effective for photon absorption in the photocatalytic process, based on the provided graph.
Atmospheric components such as oxygen (O2) and water (H2O) are crucial for the formation of surface radicals during photocatalysis.

Absorbance and Photocatalytic Activity

The absorbance in the graph shows a steady increase after a specific time interval.
A steady absorbance reading indicates that the photocatalytic reaction is proceeding efficiently.
The wavelength range of 500-800 nm is significant for photocatalytic activity because it corresponds to the visible region of the electromagnetic spectrum.

Collagen Denaturation and Dye Degradation

Collagen denaturation is observed as a change in structure with increased exposure time.
The absorption peaks corresponding to methylene blue (MB) disappear at 665 nm.
An interaction between fish scale extract and copper sulfate solution likely results in the formation of copper nanoparticles (NPs).
The control experiment with the dye solution under sunlight without NPs showed minimal degradation.
The degradation of dyes in the presence of NPs is described as a first-order reaction.
The synthesized Cu NPs achieved a 98% degradation of MB.

Cu NPs Synthesis and Characterization

Collagen denaturation is NOT a product of collagen denaturation.
The formation of Cu NPs involves the reduction of copper ions by the fish scale extract in the presence of a reducing agent, such as sodium borohydride.
The average size of the synthesized Cu NPs is 10 nm, as observed from the TEM and HRTEM studies.
The XRD pattern was recorded using Cu Kα radiation, with a wavelength of 1.5406 Å.
In the context of HRTEM results, the fringe spacing of 0.21 nm corresponds to the (111) lattice plane of Cu.

Photocatalytic Activity and Properties

The photocatalytic activity of the synthesized Cu NPs was evaluated using the degradation of methylene blue (MB) under sunlight irradiation.
The suspended solution of Cu nanoparticles was allowed to stand in the dark for 30 minutes to reach adsorption-desorption equilibrium.
The SAED pattern displays a polycrystalline nature of the synthesized Cu NPs.
Sodium borohydride acted as both a reducing and stabilizing agent for synthesizing Cu NPs.
The photocatalytic activity experiments were conducted under ambient conditions, meaning room temperature and atmospheric pressure.
The slope of the plot of ln (C0/Ct) vs irradiation time 't' represents the rate constant 'k' of the photocatalytic degradation.
Self-assembled Cu NPs are created by using fish scale extract as a bio-template.
The self-assembled Cu NPs play a critical role in enhancing the photocatalytic activity of the system.
During the synthesis of Cu NPs, heating and stirring occur at 80°C.
'Ct' represents the concentration of the dye at time 't'.
The linear relationship in the plot of ln (C0/Ct) vs time suggests that the degradation of MB follows first-order kinetics.
The synthesized Cu NPs contain 21.8 wt% of copper.
The parameter NOT mentioned as part of the formation mechanism of Cu NPs is the pressure utilized during synthesis.

Mechanism of Photocatalysis

The direct electron injection into the adsorbate is initiated by the excitation of the photocatalyst.
The protonation of the superoxide ion generates hydrogen peroxide (H2O2).
The final product of hydrogen peroxide dissociation is water (H2O).
The dual processes that occur on the surface of the photocatalyst are redox reactions and surface plasmon resonance.
Radicals such as superoxide radical anion (O2•-), hydroxyl radical (•OH), and hydroperoxyl radical (HOO•) are produced by the reaction of electrons and holes with O2 and H2O.
Excited surface plasmons contribute to the photocatalytic activity by enhancing the generation of electron-hole pairs and promoting charge separation.
The first radical formed in the sequence described is the superoxide radical anion (O2•-).
The process of electron injection into the adsorbate is best described as the transfer of an electron from the valence band of the photocatalyst to the adsorbate molecule.

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Description

Explore the fascinating process of synthesizing copper nanoparticles (Cu NPs) using fish scale extract. This quiz covers the methods used, including the electrostatic interactions in the synthesis, as well as the characterization techniques like TEM and HRTEM that confirm their properties. Test your understanding of nanoparticle formation and analysis!