Abstract：
A redox co-precipitation method was employed to synthesize CeMn homogeneous solid solutions, utilizing various alcohols as activating agents. Ethanol effectively orchestrated the precipitation of CeO2 and MnOx, promoting their co-growth. As a result, the CeMn-EA achieved 90 % toluene conversion at 218 ℃ (T90 =218 ℃) with a weight hourly space velocity (WHSV) of 48000 ml/(g·h). It also demonstrated high adaptability to increased WHSV, suggesting its potential for industrial-scale applications. The uniform dispersion of Ce and Mn accelerated the coupling between Ce3+/Ce4+ and Mn4+/Mn3+, engineering numerous oxygen vacancies, which enhanced the activation of gas-phase oxygen and the mobility of lattice oxygen. In situ DRIFTS confirmed that toluene oxidation accommodated both Langmuir-Hinshelwood (L-H) and Mars-van Krevelen (MvK) mechanisms, with benzoate identified as a pivotal intermediate. Enhanced oxygen mobility facilitated the cleavage of the benzene ring, which was the rate-determining step. Additionally, the introduction of H2O significantly enhanced the dissociation and adsorption of toluene and facilitated the activation of gas-phase oxygen. At higher temperatures, H2O could further activate lattice oxygen engaging in toluene oxidation. ENVIRONMENTAL IMPLICATION: Volatile organic compounds (VOCs) have emerged as major air pollutants due to the changes in air pollution patterns. They can act as precursors to near-surface ozone and haze. Toluene, a typical VOC, is primarily released from anthropogenic sources and poses significant risks to human health and the environment. Ce-based catalysts have been demonstrated efficiency in toluene oxidation due to their excellent oxygen storage and release properties. This study synthesized CeMn homogeneous solid solutions utilizing various alcohols as activating agents, which possessed abundant oxygen vacancies and optimum oxygen activation capacity to oxidize toluene in time.
摘要：
采用氧化还原共沉淀法合成CeMn均相固溶体，利用各种醇作为活化剂。乙醇有效地协调了CeO2和MnOx的沉淀，促进他们的共同成长。因此,CeMn-EA在218℃（T90=218℃）下实现了90％的甲苯转化率，重时空速（WHSV）为48000ml/（g·h）。它还表现出对WHSV增加的高适应性，表明其在工业规模应用中的潜力。Ce和Mn的均匀分散加速了Ce3+/Ce4+和Mn4+/Mn3+之间的耦合,工程大量的氧空位，提高了气相氧的活化和晶格氧的迁移率。原位漂移证实，甲苯氧化同时适应了Langmuir-Hinshelwood（L-H）和Mars-vanKrevelen（MvK）机制，苯甲酸酯被确定为关键的中间体。增强的氧迁移率促进了苯环的裂解，这是速率确定步骤。此外,H2O的引入显著增强了甲苯的解离和吸附，促进了气相氧的活化。在更高的温度下，H2O可以进一步激活参与甲苯氧化的晶格氧。环境含义：由于空气污染模式的变化，挥发性有机化合物（VOCs）已成为主要的空气污染物。它们可以作为近地表臭氧和雾霾的前体。甲苯,典型的VOC,主要从人为来源释放，对人类健康和环境构成重大风险。Ce基催化剂由于其优异的氧储存和释放性能而在甲苯氧化中被证明是有效的。本研究利用各种醇作为活化剂合成了CeMn均相固溶体，具有丰富的氧空位和最佳的氧活化能力，可以及时氧化甲苯。
