## 1 Introduction  
Chromium-free impregnated carbon adsorption technology is the preferred method for protection of chemical warfare agents (CWAs). However, it has disadvantages, such as short protection time, narrow protection spectrum, and easy aging and inactivation. To this end, further research on and development of alternative technologies is required. Thermal catalytic purification is one of the most commonly used technologies for the treatment of volatile organic pollutants [1; 2]; it can also be used for the removal of CWAs. The technology can be used to convert poisonous molecules into non-toxic or low-toxicity small molecules through catalysis, and has a broad spectrum, long-lasting effects, and broad application prospects for chemical protection. Long-term research has been conducted on catalysts for the thermal catalytic decomposition of CWAs. Pt catalysts are the most widely studied catalysts. Numerous reports have shown that Pt catalysts have the advantages of high catalytic oxidation activity and long protection time [3; 4; 5; 6]; however, they are prone to chemical poisoning and are difficult to regenerate after deactivation. In addition, Pt catalysts have limitations, such as high prices and scarcity of reserves [7]; therefore, the discovery of other catalysts that can achieve long-term protection against poisonous vapors is necessary. Recently, research on supported metal oxide catalysts for the thermal catalytic decomposition of CWAs has progressed [8; 9; 10; 11]. Cu catalysts have considerable potential in such cases. For example, [PERSON] et al. [12] reported the thermal catalytic decomposition performance of HCN CWAs by metal oxide catalysts (Mn, Fe, Co, Ni, and Cu) supported by activated carbon, and activated carbon-supported CuO had superior performance, with a conversion of HCN exceeding 96% between 200 and 350 \({}^{\circ}\)C. [PERSON] et al. [6] demonstrated that CuO/\(\gamma\)-Al\({}_{2}\)O\({}_{3}\) can achieve complete conversion of dimethyl methyl phosphonate (DMMP) at 400 \({}^{\circ}\)C with a protection time as long as 7.5 h. However, the supported single-component CuO catalysts reported to date do not meet the requirements for protective applications, and their thermal catalytic decomposition performance requires further improvement. Recently, [PERSON] et al. [13] reported the complete decomposition of DMMP is achieved based on crystalline ceria films under vacuum heating. Furthermore, CeO\({}_{2}\) can influence the charge transfer between catalyst components through the conversion of Ce\({}^{3+}\)/Ce\({}^{4+}\) and is often used as a catalyst promoter or carrier to improve the oxygen storage capacity of catalysts [14; 15; 16]. Therefore, it is worthwhile to prepare CuO-CeO\({}_{2}\)/\(\gamma\)-Al\({}_{2}\)O\({}_{3}\) catalyst and investigate the effect of CeO\({}_{2}\) loadings on thermal catalytic decomposition of CWAs. Herein, CuO/\(\gamma\)-Al\({}_{2}\)O\({}_{3}\) and CuO-CeO\({}_{2}\)/\(\gamma\)-Al\({}_{2}\)O\({}_{3}\) with different CeO\({}_{2}\) loadings were prepared to investigate whether the addition of CeO\({}_{2}\) could improve the thermal catalytic decomposition performance of the catalyst, and the mechanism of the catalyst was studied. The sarin simulant DMMP was selected as the target for catalytic decomposition. CuO/\(\gamma\)-Al\({}_{2}\)O\({}_{3}\) and CuO-CeO\({}_{2}\)/\(\gamma\)-Al\({}_{2}\)O\({}_{3}\) with different CeO\({}_{2}\) loadings were prepared using an equal volume impregnation method, and their thermal catalytic decomposition of DMMP was investigated. The crystal structure, pore distribution, chemical state, and interaction of the active components were studied using X-ray powder diffraction (XRD), N\({}_{2}\) adsorption, X-ray photoelectron spectroscopy (XPS), and hydrogen temperature-programmed reduction (H\({}_{2}\)-TPR). This study provides a reference for the development of high-performance catalysts for the thermal catalytic decomposition of CWAs.