Department of Building Science, Tsinghua University, Beijing 100084, PR China.
Environ Sci Technol. 2011 Jul 1;45(13):5754-60. doi: 10.1021/es2009902. Epub 2011 Jun 13.
Thermal catalytic oxidation (TCO) technology can continuously degrade formaldehyde at room temperature without added energy. However, there is very little knowledge on the TCO kinetic reaction mechanism, which is necessary in developing such air cleaners and in comparison with other air cleaning techniques. This paper addresses the problem of a novel TCO catalyst, Pt/MnO(x)-CeO(2). The experiments measuring the outlet concentrations of formaldehyde and other possible byproducts were conducted at temperatures of 25, 40, 60, 100, and 180 °C and at a series of inlet formaldehyde concentrations (280-3000 ppb). To measure the concentrations precisely and real timely, proton transfer reaction-mass spectrometry (PTR-MS) was used. We found the following from the experimental results: (1) no byproducts were detected; (2) the bimolecular L-H kinetic model best described the catalytic reaction rate; (3) the activation energy of the oxidation was about 25.8 kJ mol(-1); (4) TCO is most energy efficient at room temperature without auxiliary heating; (5) compared with photocatalytic oxidation (PCO) which needs ultraviolet light radiation, the reaction area of TCO can be much larger for a given volume so that TCO can perform much better not only in formaldehyde removal efficiency but also in energy saving.
热催化氧化（TCO）技术可以在室温下持续降解甲醛，而无需额外的能量。然而，对于这种空气净化器的开发以及与其他空气净化技术的比较，TCO 动力学反应机制的知识非常有限。本文介绍了一种新型 TCO 催化剂 Pt/MnO(x)-CeO(2)的问题。在 25、40、60、100 和 180°C 的温度下，以及一系列入口甲醛浓度（280-3000 ppb）下，进行了测量出口甲醛和其他可能副产物浓度的实验。为了精确和实时地测量浓度，使用了质子转移反应质谱（PTR-MS）。我们从实验结果中发现：（1）未检测到副产物；（2）双分子 L-H 动力学模型最能描述催化反应速率；（3）氧化的活化能约为 25.8 kJ mol(-1)；（4）TCO 在室温下无需辅助加热即可达到最高的能量效率；（5）与需要紫外线辐射的光催化氧化（PCO）相比，TCO 的反应面积对于给定的体积可以更大，因此 TCO 在去除甲醛效率和节能方面都可以表现得更好。
