Key Takeaways & Executive Findings
- •• • Ru-based catalysts exhibit superior chlorine resistance via the Deacon reaction (4HCl+O2→2Cl2+H2O), enabling sustained activity in CVOCs oxidation, whereas Pt, Pd, and Rh catalysts suffer severe deactivation by Cl species. • • The review identifies that Ru-based catalysts achieve high COx selectivity and deep oxidation of intermediates due to strong metal-support electron transfer and redox properties, with Ru being one of the most cost-effective platinum-group metals. • • Structural regulation strategies—including active component design, support selection (e.g., CeO2, TiO2, ZSM-5), and surface modification—are critical to optimizing catalytic performance and chlorine resistance, as evidenced by studies on Ru/CeO2 and Ru/TiO2 systems. • • Novel preparation methods and reaction component effects are summarized, highlighting that atomically dispersed Ru and facet-engineered supports (e.g., {001}-TiO2) can further enhance low-temperature activity and stability, as demonstrated by recent studies.
Abstract
Chlorinated volatile organic compounds (CVOCs) are volatile, difficult to degrade, and highly toxic, posing serious threats to the atmospheric environment and human health. Catalytic oxidation is currently one of the mainstream methods for CVOCs abatement, owing to its high efficiency, safety, and economic feasibility, and its key aspect lies in the design and development of high-performance catalysts. In the catalytic oxidation of CVOCs, the poisoning effect of chlorine species on catalysts severely restricts catalytic performance. Ru-based catalysts, which exhibit excellent catalytic oxidation activity toward CVOCs and favorable chlorine-resistant performance, have been widely studied in recent years. This paper reviews the latest research progress on Ru-based catalysts for the catalytic oxidation of CVOCs. The mechanism of catalytic oxidation of CVOCs by Ru-based catalysts is elucidated through a systematic analysis of the relevant literature. Furthermore, the strategies for the design and structural regulation of Ru-based catalysts are outlined from the perspectives of active components, supports, and surface modification. Finally, novel preparation methods for Ru-based catalysts and the influence of reaction components on catalytic performance are summarized. Future research directions in this field are also prospected, aiming to provide a reference for the subsequent design and development of high-performance Ru-based catalysts suitable for complex operating conditions.
1. Introduction
Chlorinated volatile organic compounds (CVOCs) are a class of hazardous air pollutants characterized by high volatility, resistance to degradation, and acute toxicity. They are emitted from diverse industrial sources including mechanical manufacturing, petrochemical processing, pharmaceuticals, and coating operations. Common CVOCs such as dichloromethane (DCM), 1,2-dichloroethane (1,2-DCE), trichloroethylene (TCE), and chlorobenzene (CB) are regulated as priority pollutants by environmental agencies in China, the United States, and the European Union. Conventional abatement technologies—absorption, adsorption, condensation, and direct combustion—suffer from high energy consumption, secondary pollution, or limited efficiency. Catalytic oxidation stands out as a promising alternative due to its low light-off temperature, high efficiency, and minimal byproduct formation. However, the Achilles' heel of catalytic oxidation is the deactivation of catalysts by chlorine species generated during reaction, which poisons active sites and shortens catalyst lifespan.
Noble metal catalysts, particularly Pt, Pd, and Rh, exhibit high intrinsic activity but are notoriously susceptible to chlorine poisoning. In contrast, ruthenium (Ru)-based catalysts have emerged as a robust solution, leveraging the Deacon reaction to continuously remove surface chlorine and maintain catalytic stability. Ru also offers strong metal-support interactions and redox versatility, enabling deep oxidation of intermediates and high COx selectivity. Moreover, Ru is among the least expensive platinum-group metals, enhancing economic viability for industrial deployment. This review systematically examines the mechanistic underpinnings of Ru-based catalysts in CVOCs oxidation, delineates design strategies for active components, supports, and surface modifications, and highlights recent advances in preparation methods and reaction engineering. By synthesizing current knowledge, this work aims to guide the rational development of high-performance, chlorine-resistant Ru catalysts for complex industrial flue gas streams.
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ZHU Xinbao, YANG Wenhao, ZHAO Dongyue, SONG Haitao (2026). Research progress on Ru-based catalysts for catalytic oxidation of chlorinated volatile organic compounds. Journal of Environmental Engineering Technology. https://doi.org/10.13205/j.hjgc.202608018
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Frequently Asked Questions
What is the primary deactivation mechanism for noble metal catalysts in CVOCs oxidation, and how do Ru-based catalysts overcome it?
Pt, Pd, and Rh catalysts suffer from poisoning by chlorine species (Cl*) generated during CVOCs oxidation, which block active sites and reduce activity. Ru-based catalysts mitigate this via the Deacon reaction (4HCl+O2→2Cl2+H2O), which rapidly removes surface chlorine, thereby maintaining catalytic activity and stability.
How does the choice of support influence the catalytic performance of Ru-based catalysts for CVOCs oxidation?
Support materials such as CeO2, TiO2, and ZSM-5 provide specific surface areas, redox properties, and acidity that affect Ru dispersion, metal-support interactions, and chlorine resistance. For instance, Ru/CeO2 with tailored morphology enhances oxygen mobility and redox cycles, while Ru/TiO2 with {001} facets promotes interfacial charge transfer and Ru0↔Ru4+ circulation, improving low-temperature activity.
What are the key structural regulation strategies to enhance the chlorine resistance and activity of Ru-based catalysts?
Strategies include optimizing Ru particle size (e.g., atomically dispersed Ru), selecting supports with suitable facets and redox properties, and surface modification with additives like Nb2O5 or V2O5 to adjust acidity and oxygen vacancies. These modifications enhance Deacon reaction kinetics and prevent chlorine accumulation.
What are the reported performance metrics for Ru-based catalysts in terms of conversion efficiency and stability?
Specific metrics are not detailed in the provided text, but the review indicates that Ru-based catalysts achieve high COx selectivity and stable performance over extended periods. For example, atomically dispersed Ru on supports shows low-temperature activity for o-dichlorobenzene oxidation, and Ru/CeO2 with specific morphologies exhibits enhanced activity for various CVOCs.
What are the main challenges and future directions for Ru-based catalysts in industrial applications?
Challenges include scaling up synthesis, ensuring long-term stability under real flue gas conditions (presence of water, sulfur, etc.), and reducing cost further. Future directions involve developing novel preparation methods, understanding structure-activity relationships at the molecular level, and designing catalysts for complex multi-component CVOCs streams.
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