Abstract：
Formaldehyde (FA), a carcinogenic oxygenated volatile organic compound, is present ubiquitously in indoor air. As such, it is generally regarded as a critical target for air quality management. The oxidative removal of FA under dark and room-temperature (RT) conditions is of practical significance. A series of ternary nickel-cobalt-manganese oxide-supported platinum catalysts (Pt/NiCoMnO4) have been synthesized for FA oxidative removal at RT in the dark. Their RT conversion values for 50 ppm FA (XFA) at 5,964 h-1 gas hourly space velocity (GHSV) decrease in the following order: 1 wt% Pt/NiCoMnO4 (100 %) > 0.5 wt% Pt/NiCoMnO4 (25 %) > 0.05 wt% Pt/NiCoMnO4 (14 %) > NiCoMnO4 (6 %). The catalytic performance of 1 wt% Pt/NiCoMnO4 has been examined further under the control of various process variables (e.g., catalyst mass, flow rate, relative humidity, FA concentration, time on stream, and molecular oxygen content). The catalytic oxidation of FA at low temperatures (e.g., RT and 60 °C) is accounted for by Langmuir-Hinshelwood mechanism (single-site competitive-adsorption), while Mars van Krevelen kinetics is prevalent at higher temperatures. In situ diffuse-reflectance infrared Fourier-transform spectroscopy reveals that FA oxidation proceeds through a series of reaction intermediates such as DOM, HCOO-, and CO32-. Based on the density functional theory simulations, the unique electronic structures of the nearest surface atoms (platinum and nickel) are suggested to be responsible for the superior catalytic activity of Pt/NiCoMnO4.
摘要：
甲醛(FA),一种致癌的含氧挥发性有机化合物，普遍存在于室内空气中。因此，它通常被视为空气质量管理的关键目标。在黑暗和室温（RT）条件下氧化去除FA具有实际意义。已合成了一系列三元镍-钴-锰氧化物负载的铂催化剂（Pt/NiCoMnO4），用于在黑暗中在室温下氧化去除FA。在5,964h-1气时空速（GHSV）下，它们对50ppmFA（XFA）的RT转化值按以下顺序降低：1wt％Pt/NiCoMnO4（100％）>0.5wt％Pt/NiCoMnO4（25％）>0.05wt％Pt/NiCoMnO4（14％）>NiCoMnO4（6％）。在各种工艺变量的控制下，进一步检查了1wt％Pt/NiCoMnO4的催化性能（例如，催化剂质量，流量,相对湿度,FA浓度,时间在流,和分子氧含量)。FA在低温下的催化氧化(例如，RT和60°C）由Langmuir-Hinshelwood机制（单位点竞争吸附）解释，而MarsvanKrevelen动力学在较高的温度下很普遍。原位漫反射红外傅里叶变换光谱表明，FA氧化是通过DOM等一系列反应中间体进行的，HCOO-,和CO32-。基于密度泛函理论模拟,建议最近的表面原子（铂和镍）的独特电子结构负责Pt/NiCoMnO4的优异催化活性。
