ABSTRACT

Volatile organic compounds (VOCs) have caused a serious threat to the atmosphere and human health. Therefore, it is of great significance to exploit effective catalytic materials for the safe and effective catalytic elimination of VOCs. Herein, Ag-MnO_x-ACF composite catalysts were constructed via a two-step impregnation strategy and used for catalytic toluene degradation. A remarkable low-temperature catalytic activity (T₁₀₀= 50℃), excellent stability, as well as CO₂ selectivity (80%) were achieved over the Ag-MnO_x-ACF catalyst. A series of characterizations indicated that the unique manganese defects structure of birnessite phase manganese oxide played an essential role for toluene oxidation, which was conducive to generating surface adsorbed oxygen. The higher ratio of Mn³⁺/Mn⁴⁺, abundant surface adsorbed oxygen and highly dispersed Ag species were determined to significantly facilitate toluene degradation. The mechanism of efficient degradation of toluene at low temperature was proposed. O₃ and H₂O molecules were activated via surface hydroxyl and Mn defects on Ag-MnO_x-ACF to produce sufficient •OH, enhancing the degradation performance of toluene. We provide a new idea for the catalytic oxidation of benzene VOCs at low even room temperatures.

摘要

挥发性有机化合物 (VOC) 已对大气和人类健康造成严重威胁。因此，开发有效的催化材料对于安全有效地催化消除VOCs具有重要意义。在此，Ag-MnO _x -ACF 复合催化剂通过两步浸渍策略构建，并用于催化甲苯降解。与Ag-MnO _x相比，实现了显着的低温催化活性（T ₁₀₀ = 50℃），优异的稳定性以及CO _{2选择性（80％）}-ACF催化剂。一系列表征表明，水钠锰矿相氧化锰独特的锰缺陷结构对甲苯氧化起着至关重要的作用，有利于产生表面吸附氧。较高的 Mn ³⁺ /Mn ⁴⁺比率、丰富的表面吸附氧和高度分散的 Ag 物种被确定为显着促进甲苯降解。提出了甲苯在低温下高效降解的机理。O ₃和 H ₂ O 分子通过 Ag-MnO _{x上的表面羟基和 Mn 缺陷被激活}-ACF产生足够的•OH，增强甲苯的降解性能。我们为苯VOCs在低温甚至室温下的催化氧化提供了一个新思路。