Ozone & VOC Catalysts Synergy: Mechanisms and Configs

The synergistic use of ozone decomposition catalysts and VOC catalysts in exhaust gas treatment essentially couples ozone decomposition with VOCs oxidation within the same catalytic system—the highly reactive oxygen species (O*, ·OH, ·O₂⁻, etc.) generated from ozone decomposition on the catalyst surface serve as in situ oxidants for deep oxidation of VOCs, while the oxidation process of VOCs consumes these reactive species, preventing their recombination or discharge into the atmosphere as secondary pollution. The core chemical basis of this synergy lies in the fact that active sites on the catalyst surface (oxygen vacancies, transition metal ion pairs, etc.) function both as catalytic centers for ozone decomposition and as reaction centers for VOCs oxidation. The design of bifunctional catalysts—simultaneously configuring active sites for ozone decomposition and VOCs activation on the same catalyst—is the key strategy to realize this synergistic effect. Through rational spatial arrangement of active sites and electronic structure tuning, the synergistic system can dramatically lower the catalytic oxidation temperature of VOCs from above 200°C in traditional thermal catalysis to ambient‑to‑150°C range, while achieving in situ elimination of ozone.

1. Chemical Basis of Synergy: Coupling Mechanism of Ozone Decomposition and VOCs Oxidation

The ozone molecule consists of three oxygen atoms and possesses strong oxidizing power (redox potential 2.07 V). On the catalyst surface, catalytic decomposition of ozone is the prerequisite for VOCs oxidation. Ozone first adsorbs onto oxygen vacancies or transition metal ion active sites on the catalyst surface and undergoes electron transfer, breaking the O–O bond to generate highly reactive species such as atomic oxygen (O*), superoxide radicals (·O₂⁻), and hydroxyl radicals (·OH). The oxidation potentials of these reactive oxygen species are significantly higher than that of ozone itself.

On catalyst surfaces with oxygen vacancies, the highly reactive oxygen species generated from ozone decomposition react with VOCs molecules adsorbed on adjacent active sites, deeply oxidizing VOCs into CO₂ and H₂O. The generation of reactive species and the oxidation of VOCs proceed in a relay manner on spatially adjacent sites—ozone decomposes on Lewis acid sites to generate reactive oxygen, while VOCs are adsorbed and pre‑activated on neighboring Brønsted acid sites, allowing short‑lived reactive species to be efficiently utilized by VOCs molecules before diffusion deactivation. Mechanistic studies typically divide the overall process into ozone decomposition and organic oxidation—the key species responsible for organic oxidation are precisely the reactive oxygen generated from catalytic ozone decomposition.

The essence of this coupling mechanism is that ozone decomposition catalysts and VOC catalysts do not function as two independent units; instead, they are functionally linked through reactive oxygen species on the same catalyst surface—ozone decomposition provides “in situ” oxidants for VOCs oxidation, while VOCs oxidation consumes the reactive oxygen generated from ozone decomposition, preventing ineffective recombination of reactive species.

2. Design Strategies for Bifunctional Catalysts

The most direct route to achieving synergy between ozone decomposition and VOCs oxidation is the design of bifunctional catalysts—co‑configuring active sites for ozone decomposition and VOCs activation on the same catalyst.

Taking cobalt‑vanadium bimetallic oxide catalysts (Co₃O₄–V₂O₅/SiO₂) as an example: in the 50–150°C temperature range, the VOCs oxidation efficiency of the dual‑component catalyst is significantly superior to that of single‑component Co₃O₄/SiO₂ or V₂O₅/SiO₂ systems. Mechanistic studies indicate that the ozone decomposition step (generating highly active atomic oxygen O*) occurs on Co sites, while the activation step of VOCs proceeds on V sites. Each site performs its own function in a synergistic relay—this design, which separates “decomposition” and “oxidation” on different active sites, avoids competitive adsorption between ozone and VOCs on a single site and greatly enhances overall reaction efficiency.

In manganese‑based catalyst systems, by tuning the hydroxyl microenvironment on the catalyst surface, spatially adjacent Lewis acid sites and Brønsted acid sites can be constructed. Lewis acid sites promote ozone adsorption and decomposition to generate reactive oxygen species; Brønsted acid sites preferentially adsorb and pre‑activate VOCs molecules such as toluene. The close spatial proximity of the two sites ensures that short‑lived reactive oxygen species can be efficiently utilized by VOCs molecules before diffusion loss. Optimized MnOx/γ‑Al₂O₃ catalysts achieve complete removal of toluene at room temperature, with a mineralization efficiency of 87.51%.

Copper‑doped α‑MnO₂ catalysts also exhibit excellent ozone‑assisted catalytic oxidation performance. Under mild temperature conditions of 80–100°C, this catalytic system achieves conversion efficiencies exceeding 80% for a variety of VOCs including toluene, trimethylamine, ethyl acetate, and ethanol.

Manganese‑based mullite catalysts represent another typical case of bifunctional design. Mullite catalysts with Mn³⁺ and Mn⁴⁺ dual active sites—Mn³⁺ sites possess ultra‑high ozone decomposition activity (0.29 eV) capable of generating highly active atomic oxygen O* on the catalyst surface, while Mn⁴⁺ sites tend to adsorb benzene and other VOCs molecules. Through the synergistic action of the dual active sites in the reaction, this catalyst achieves complete removal of benzene and ozone over a wide temperature range from ‑20°C to 50°C, maintaining 100% conversion of both benzene and ozone for 8 hours at room temperature. This demonstrates that through rational active‑site design, non‑noble metal oxide catalysts are fully capable of simultaneously carrying out both ozone decomposition and VOCs oxidation on the same material.

3. System Configuration for Synergistic Processes

In actual industrial exhaust gas treatment, the synergy between ozone decomposition catalysts and VOC catalysts can be realized through rational configuration of catalyst beds.

Option 1: Single‑bed bifunctional catalyst. A bifunctional catalyst possessing both ozone decomposition and VOCs oxidation activity is loaded into a single reactor, and the exhaust gas mixed with ozone passes through the catalyst bed in one step to complete VOCs catalytic oxidation. This configuration is the most straightforward, with low capital investment and simple operation and maintenance, suitable for scenarios with relatively stable VOCs concentration and less complex composition.

Option 2: Series‑bed staged treatment. The exhaust gas first passes through a high‑temperature catalytic oxidation zone for preliminary treatment, then enters an ozone catalytic oxidation zone for deep polishing. The front‑end high‑temperature catalytic oxidation removes the majority of VOCs, while the rear‑end ozone catalytic oxidation utilizes the strong oxidizing power of ozone to further mineralize residual VOCs. This configuration is suitable for high‑concentration, complex‑composition exhaust gases, fully leveraging the complementary advantages of the two catalytic processes.

Option 3: Adsorption‑ozone catalytic oxidation coupling. VOCs‑laden exhaust gas first passes through an adsorption unit for concentration, and the desorbed concentrated gas then enters the ozone catalytic oxidation unit for catalytic decomposition. The adsorption unit enriches VOCs, improving the treatment efficiency of the subsequent ozone catalytic oxidation; the ozone catalytic oxidation unit completely mineralizes the desorbed gas, avoiding frequent replacement or regeneration of the adsorbent. This configuration is particularly suitable for large‑volume, low‑concentration VOCs abatement.

Regardless of which configuration is adopted, ozone dosage is a critical parameter that requires precise control. Studies show that under conditions of an ozone‑to‑toluene ratio of 3:1 and a residence time of approximately 0.3 seconds, toluene degradation efficiency can reach 98%. Excess ozone causes resource waste and secondary pollution, while insufficient ozone fails to provide enough reactive oxygen species for deep VOCs oxidation.

4. Practical Effects of Synergistic Performance

The practical effects of synergistic use of ozone decomposition catalysts and VOC catalysts can be evaluated from three dimensions: reaction temperature, removal efficiency, and ozone elimination.

Reaction temperature is the most intuitive manifestation of the synergistic effect. Traditional thermal catalytic oxidation of VOCs typically requires temperatures above 200°C. In the ozone‑assisted catalytic oxidation system, because ozone decomposition directly generates reactive oxygen species, VOCs oxidation can be accomplished at ambient‑to‑150°C or even lower temperatures. Research shows that using alumina‑supported manganese oxide catalysts, catalytic ozonation of alkane VOCs can be achieved at temperatures as low as 25°C. The significant reduction in temperature translates to substantial energy savings and enhanced system safety.

In terms of removal efficiency, bifunctional catalyst systems demonstrate excellent degradation performance for a wide range of VOCs. Optimized MnOx/γ‑Al₂O₃ catalysts achieve complete removal of toluene at room temperature. Manganese‑based mullite catalysts reach 100% benzene conversion at room temperature with COₓ selectivity around 90%. Cobalt‑chromium bimetallic catalysts coupled with ozone oxidation achieve essentially complete removal of multi‑component VOCs and maintain long‑term stability. Rare‑earth composite catalysts combined with ozone achieve VOCs removal rates exceeding 95% at room temperature.

Simultaneous ozone elimination is a unique advantage of the synergistic process. In traditional ozone oxidation processes, unreacted ozone discharged into the atmosphere causes secondary pollution. In the bifunctional catalyst system, ozone is efficiently decomposed on the catalyst surface into reactive oxygen species that are immediately consumed for VOCs oxidation, achieving in situ utilization and elimination of ozone. Optimized catalysts achieve complete removal of residual ozone at room temperature. This “two birds with one stone” effect—simultaneously degrading VOCs and eliminating ozone secondary pollution—is a key competitive advantage of the synergistic process over other VOCs treatment technologies.

5. Conclusion

The synergistic use of ozone decomposition catalysts and VOC catalysts fundamentally couples the two reaction processes—ozone decomposition and VOCs oxidation—through active sites on the catalyst surface. The highly reactive oxygen species (O*, ·OH, etc.) generated from ozone decomposition provide “in situ” oxidants for low‑temperature VOCs oxidation, while VOCs oxidation consumes these reactive species, preventing their recombination and forming a positive cycle. The design of bifunctional catalysts—co‑configuring active sites for ozone decomposition and VOCs activation on the same material—is the core strategy for achieving this synergy. At the engineering application level, different configuration options—single‑bed bifunctional catalyst, series‑bed staged treatment, or adsorption‑ozone catalytic oxidation coupling—can be flexibly adopted to address various exhaust gas conditions.

For industrial enterprises facing VOCs abatement pressure, the synergistic use of ozone decomposition catalysts and VOC catalysts offers a technically feasible pathway that balances low‑temperature high efficiency with ozone secondary pollution control. This technical route not only drastically lowers the catalytic oxidation temperature of VOCs from the traditional >200°C to ambient‑to‑150°C range, reducing energy consumption and safety risks, but also achieves in situ ozone elimination, avoiding secondary pollution caused by unreacted ozone discharge in traditional ozone oxidation processes. With continued advances in bifunctional catalyst material design—such as oxygen vacancy engineering, dual‑active‑site tuning, hydroxyl microenvironment optimization, and other strategies—the synergistic effect of ozone decomposition and VOCs catalytic oxidation is expected to play an even greater role in a broader range of industrial exhaust treatment scenarios.

author：Gloria
date:2026-07-14