Semiconductor Catalysts
Semiconductor Catalysts - Related Videos
12:36
Semiconductors
0 Views •
2023
Source: Derek Wilson, Asantha Cooray, PhD, Department of Physics & Astronomy, School of Physical Sciences, University of California, Irvine, CA Semiconductors are materials whose ability to conduct an electrical current depends strongly on their temperature and level of impurity. The most common type of semiconductor material is crystalline silicon. Most pure semiconductors are not outstanding conductors; to improve conductivity, a pure semiconductor is often combined or "doped" with an...
01:22
Semiconductors
0 Views •
2024
There is variation in the electrical conductivity of materials - metals, semiconductors, and insulators that are showcased with the help of the energy band diagrams. Metals such as copper (Cu), zinc (Zn), or lead (Pb) have low resistivity and feature conduction bands that are either not fully occupied or overlap with the valence band, making a bandgap non-existent. This allows electrons in the highest energy levels of the valence band to easily transition to the conduction band upon gaining...
11:14
Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope
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Cited by 4 •
2016
The optical, electrical, and structural properties of dislocations and of grain boundaries in semiconductor materials can be determined by experiments performed in a scanning electron microscope. Electron microscopy has been used to investigate cathodoluminescence, electron beam induced current, and diffraction of backscattered electrons.
11:15
HKUST-1 as a Heterogeneous Catalyst for the Synthesis of Vanillin
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Cited by 12 •
2016
The conversion of trans-ferulic acid to vanillin was achieved by heterogeneous catalysis. HKUST-1 was employed in this synthesis and the essential step in the catalytic process was the generation of unsaturated metal sites. Thus, when the catalyst was activated under vacuum, full vanillin conversion (yield of 95%) was obtained.
09:53
Predicting Catalyst Extrudate Breakage Based on the Modulus of Rupture
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Cited by 3 •
2018
Here we present a protocol to measure the modulus of rupture of an extruded catalyst and the breakage of said catalyst extrudates by collision against a surface or by compression in a fixed bed.
FAQs
Band structure determines which electronic states can participate when a material is illuminated or electrically biased. The resulting mobile electrons and holes do not act identically: they reach the surface and drive reduction and oxidation reactions, respectively. This electronic behavior connects the catalyst’s internal energy structure to its chemical reactivity.
Recombination reduces performance because electrons and holes can disappear before reaching the surface. Efficient charge separation instead preserves more carriers for interfacial chemistry, increasing the opportunity for oxidation or reduction of pollutants. In environmental systems, this makes carrier migration and separation important when evaluating photocatalytic performance.
Performance depends on more than the catalyst identity. Light absorption determines how much incoming illumination can generate usable carriers, while surface area affects access to reactive surface sites. Reaction conditions also influence the chemistry occurring at that interface. Considering these variables together helps explain changes in pollutant degradation, disinfection, or energy-conversion results.
A practical environmental treatment workflow begins by bringing the semiconductor photocatalyst into contact with contaminated air or water and supplying illumination or an electrical bias. Generated carriers then migrate to the surface, where oxidation and reduction reactions act on contaminants. Researchers can assess the outcome through pollutant degradation or disinfection, depending on the treatment goal.
Semiconductor catalysts are relevant to environmental remediation because the same surface reactions can address contaminants in different media. Titanium dioxide photocatalysts are identified for degrading organic pollutants in both air and water, and for disinfecting contaminants. These applications extend the method beyond a single treatment setting while remaining dependent on reaction conditions and light-driven carrier behavior.
Environmental research also uses these materials for energy-related reactions rather than only pollutant removal. Solar-driven water splitting and carbon dioxide reduction are cited applications, linking illumination, charge transport, and surface redox chemistry to energy conversion. In these systems, light absorption and charge separation remain central because limited carrier availability can constrain reactions at the surface.