Band gaps - Catalysis

What is a Band Gap?

A band gap is the energy difference between the valence band and the conduction band in a solid material. It is a crucial parameter in determining a material's electrical conductivity. In the context of catalysis, band gaps play a vital role in semiconductor-based catalysts, particularly in photocatalysis.

Why is the Band Gap Important in Catalysis?

The band gap determines the wavelengths of light that a semiconductor can absorb and convert into chemical energy. This property is essential for processes like photocatalytic water splitting and photocatalytic degradation of pollutants. A smaller band gap means the material can absorb visible light, while a larger band gap restricts absorption to ultraviolet light.

How Does the Band Gap Influence Catalytic Activity?

The catalytic activity of a semiconductor is highly dependent on its band gap. A smaller band gap can lead to higher photocatalytic efficiency because it allows the material to harvest more sunlight. However, too small a band gap can result in rapid recombination of electron-hole pairs, reducing efficiency. Therefore, a balance must be struck to optimize performance.

What Materials Are Commonly Used in Band Gap Engineering for Catalysis?

Titanium dioxide (TiO2) is one of the most studied materials due to its stability and strong oxidative power, but its large band gap (~3.2 eV) limits its activity to UV light. Other materials like zinc oxide (ZnO), cadmium sulfide (CdS), and graphene-based composites are also explored to tune the band gap for broader light absorption.

What Techniques are Used to Modify the Band Gap?

Several techniques are employed to modify the band gap of materials for catalytic applications:

Doping: Introducing foreign atoms into the semiconductor to create energy levels within the band gap.
Surface modification: Altering the surface properties to improve light absorption and charge separation.
Heterojunctions: Combining two different semiconductors to form a junction that enhances charge separation and extends the absorption spectrum.
Composites: Integrating materials with different band gaps to achieve a synergistic effect.

What are the Challenges in Band Gap Engineering?

Despite the potential benefits, band gap engineering faces several challenges:

Recombination: Rapid recombination of electron-hole pairs can negate the benefits of a smaller band gap.
Stability: Some materials with desirable band gaps may degrade under operating conditions.
Cost: High-quality materials and complex modification techniques can be expensive.

What are the Future Directions?

The future of band gap engineering in catalysis lies in developing new materials and techniques to achieve optimal performance. Research is ongoing in areas like perovskites, 2D materials, and quantum dots to create efficient and stable catalysts that can harness a broader spectrum of sunlight.

Relevant Publications

Crystal Growth of Quaternary AkRESiS (Ak = Ca and Sr; RE = La-Tb) Thiosilicates Using Flux-Assisted Boron Chalcogen Mixture Method: Exploring X-ray Scintillation, Luminescence, and Magnetic Properties.

Issue Release: 2024

Band gap engineering and photoluminescence tuning in halide double perovskites.

Issue Release: 2024

Beyond metals: theoretical discovery of semiconducting MAX phases and their potential application in thermoelectrics.

Issue Release: 2024

A detailed study of the electronic and optical properties of germanium nanotubes.

Issue Release: 2024

Advancing optoelectronic characteristics of Diketopyrrolopyrrole-Based molecules as donors for organic and as hole transporting materials for perovskite solar cells.

Issue Release: 2024

A Theoretical Investigation for Exploring the Potential Performance of Non-Fullerene Organic Solar Cells Through Side-Chain Engineering Having Diphenylamino Groups to Enhance Photovoltaic Properties.

Issue Release: 2024

Terahertz Polarization Isolator Using Two-Dimensional Square Lattice Tellurium Rod Array.

Issue Release: 2024

Experimental and Theoretical Investigations of Direct and Indirect Band Gaps of WSe.

Issue Release: 2024

The Grafting of Hydroxyaromatic Organics within Layered Perovskites via a Microwave-Assisted Method.

Issue Release: 2024

Capillary effect-based selective sealing strategy for increasing piezoelectric MEMS speaker performance.

Issue Release: 2024

Excitation/emission-enhanced heterostructure photonic crystal array synergizing with \"DD-A\" FRET entropy-driven circuit for high-resolution and ultrasensitive analysis of ctDNA.

Issue Release: 2024

Blue-Light-Excitable Red-Emitting Organic Antimony Halides as a Reversible Humidity Sensor.

Issue Release: 2024

Evidence of Energy and Hole Transfer between 2D CdSe0.7Te0.3 Alloy NPLs with Porphyrin Molecules.

Issue Release: 2024

A way to identify whether a DFT gap is from right reasons or error cancellations: The case of copper chalcogenides.

Issue Release: 2024

Synthesis of Ultrawide Band Gap TeO Nanoparticles by Pulsed Laser Ablation in Liquids: Top Ablation versus Bottom Ablation.

Issue Release: 2024

Nanostructured CeO photocatalysts: optimizing surface chemistry, morphology, and visible-light absorption.

Issue Release: 2024

Functionalized fennel extract-mediated alumina/cerium oxide nanocomposite potentiometric sensor for the determination of diclofenac sodium medication.

Issue Release: 2024

Unravelling co-catalyst integration methods in Ti-based metal-organic gels for photocatalytic H production.

Issue Release: 2024

Interlayer Polymerization to Construct a Fully Conjugated Covalent Organic Framework as a Metal-Free Oxygen Reduction Reaction Catalyst for Anion Exchange Membrane Fuel Cells.

Issue Release: 2024

Effective Charge Collection of Electron Transport Layers for High-Performance Quantum Dot Infrared Solar Cells.

Issue Release: 2024

How Can Researchers Build Strong Professional Relationships?

What Standards are Relevant to Catalysis?

What are Some Common Microwave Absorptive Materials?

How can solvent-free conditions be advantageous in catalysis?

What is Post Combustion Capture?

What are Some Practical Applications of Molecular Weight Considerations in Catalysis?

Who are some notable members of the Royal Society in the field of Catalysis?

Why is There Career Uncertainty in Catalysis?

How Does Thermal Cracking Work?

Why is Mechanistic Insight Important?

Partnered Content Networks

Relevant Topics