Messi Biology states that catalytic materials play a crucial role in environmental governance, energy conversion, and industrial chemistry. Magnesium ferrite (MgFe₂O₄) is an important ferrite material with good catalytic activity, and the introduction of magnesium oxide (MgO) can further optimize its performance, giving it greater application potential in fields such as catalytic decomposition, gas sensing, and photocatalysis. The following are the main roles of magnesium oxide in magnesium ferrite catalytic applications:
1. Enhancing Catalytic Decomposition Capability
Magnesium ferrite is often used for the catalytic degradation of organic pollutants, such as decomposing organic dyes and volatile organic compounds. However, under certain conditions, its catalytic activity may be limited. The introduction of magnesium oxide can increase its surface basicity, thereby enhancing its adsorption capacity for pollutants and making catalytic reactions more efficient. For example, in advanced oxidation processes such as Fenton reactions and persulfate activation, magnesium oxide-modified magnesium ferrite can accelerate the generation of free radicals and improve pollutant degradation efficiency.
2. Improving Gas Sensing Performance
Magnesium ferrite can serve as a gas sensing material, detecting the presence of specific gases such as nitrogen dioxide, carbon monoxide, or ammonia. However, standalone magnesium ferrite has low sensitivity at low temperatures. The addition of magnesium oxide can increase its surface active sites, making gas adsorption and oxidation reactions occur more easily, thereby improving the sensor’s response speed and sensitivity. Furthermore, magnesium oxide can adjust the band structure of magnesium ferrite, allowing it to maintain good detection capabilities at lower temperatures, which helps in developing low-power gas sensors.
3. Enhancing Photocatalytic Activity
Photocatalysis utilizes sunlight or artificial light sources to drive catalytic reactions, such as degrading water pollutants or water splitting for hydrogen production. Magnesium ferrite itself possesses certain photocatalytic capabilities, but its light absorption range is narrow, and electron-hole recombination easily occurs, reducing catalytic efficiency. The addition of magnesium oxide can enhance its photocatalytic performance in the following ways:
- Enhancing electron mobility: Magnesium oxide can reduce the recombination of photogenerated electrons and holes, extending the duration of catalytic reactions.
- Optimizing band structure: Magnesium oxide can adjust the band gap width of magnesium ferrite, enabling it to absorb light energy across a broader spectral range, thereby increasing catalytic activity.
- Enhancing stability: Magnesium oxide helps reduce catalyst deactivation during long-term use and improves its durability in harsh environments.
4. Promoting Oxygen Reduction and Oxidation Reactions
In fields such as fuel cells and electrocatalysis, magnesium oxide-modified magnesium ferrite can promote oxygen reduction and oxidation reactions, improving energy conversion efficiency. For example, in metal-air batteries or supercapacitors, magnesium oxide can act as a co-catalyst, enhancing the electrochemical activity of magnesium ferrite, reducing the cost of using noble metal catalysts, and improving battery cycle stability.
5. Applications in Industrial Catalysis
Magnesium oxide-modified magnesium ferrite can be used in common chemical reactions in catalytic synthesis industries, such as methane partial oxidation, alcohol dehydrogenation, and desulfurization. The addition of magnesium oxide can not only increase the catalyst’s activity but also enhance its resistance to poisoning, allowing it to maintain high catalytic performance even in sulfur-containing or chlorine-containing environments. Furthermore, since both magnesium ferrite and magnesium oxide possess good thermal stability, this composite catalyst can operate long-term in high-temperature environments, reducing catalyst deactivation issues.