What Causes Ozone Decomposition Catalysts to Deactivate?

I. Three Core Causes of Ozone Decomposition Catalyst Deactivation

Poisoning by Toxic Substances (Most Common Cause)

Sulfur oxides (SO₂), chlorinated hydrocarbons (such as dichloromethane), and heavy metal ions (Pb, Hg) in industrial waste gas or air can irreversibly bind to active sites on catalysts (such as MnO₂ and TiO₂), blocking the active centers and causing ozone catalyst poisoning. For example, elemental sulfur forms stable sulfides with metal ions on the catalyst surface, directly destroying the catalytic structure.

Carbon Deposits and Impurity Blockage
During the reaction, incomplete oxidation of organic waste gases (such as VOCs) can generate carbon deposits, or dust and aerosols can adhere to the catalyst surface, blocking pores and channels, preventing ozone from reaching active sites and causing "physical deactivation." This is particularly pronounced in scenarios with high organic waste gas concentrations.

High-Temperature Sintering and Structural Collapse
If the reaction temperature exceeds the catalyst's tolerance threshold (most ozone catalysts can withstand temperatures ≤300°C), the catalyst support (such as honeycomb ceramics or activated carbon) can sinter, causing active component particles to agglomerate and significantly reducing the specific surface area, ultimately leading to permanent loss of ozone decomposition catalyst activity.

II. How to Prevent Ozone Decomposition Catalyst Deactivation?

Pretreatment of the Feed Gas: Install a high-efficiency filter before the catalyst to remove dust, aerosols, and toxic substances such as sulfur and chlorine, reducing "toxic exposure" at the source.
Control the reaction temperature: Use a temperature control system to maintain the reaction temperature within the catalyst's optimal range (usually 80-250°C) to avoid high-temperature sintering.
Choose a poison-resistant carrier: Prefer modified carriers that are resistant to sulfur and chlorine (such as Al₂O₃-TiO₂ composite carriers) to enhance the catalyst's resistance to deactivation.
Perform regular light maintenance: Use hot air (150-200°C) to purge the catalyst surface every 3-6 months to remove light carbon deposits and slow deactivation.

III. Which deactivated ozone decomposition catalysts can be regenerated?

Not all deactivated catalysts need to be scrapped. The following two types can be reactivated through regeneration:

Deactivation caused by light carbon deposits or reversible poison adsorption: 

High-temperature oxidation (removing carbon by burning with hot air at 250-300°C) or acid-base elution (removing reversible poisons with dilute hydrochloric acid or sodium hydroxide solution) can be used. After regeneration, activity can be restored to 70%-90% of new catalyst. Physical clogging and deactivation: 

If the pores are simply clogged by dust or impurities, high-pressure air backwashing or ultrasonic cleaning can restore permeability and activity.

However, catalysts that have collapsed due to high-temperature sintering or severe heavy metal poisoning have completely destroyed their active sites and cannot be regenerated, requiring replacement.

In summary, properly controlling reaction conditions and ensuring proper raw material pretreatment are key to preventing deactivation of ozone decomposition catalysts. Regenerating even slightly deactivated catalysts can significantly reduce operating costs, providing a more economical solution for ozone treatment.

author: Hazel
date: 2025-09-30