Catalytic performance and mechanism of a Pt/TiO2 catalyst for the oxidation of formaldehyde at room temperature
Catalytic performance and mechanism of a Pt/TiO2 catalyst for the oxidation of formaldehyde at room temperature
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DOI：
10.1016/j.apcatb.2005.12.010
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发表时间：
2006-05-15
影响因子：
22.1
通讯作者：
Tanaka, Ken-ichi
中科院分区：
文献类型：
--
作者：
Zhang, Changbin;He, Hong;Tanaka, Ken-ichi
考察并比较了TiO 2负载贵金属（Pt、Rh、Pd和Au）催化剂对甲醛（HCHO）的催化氧化性能。其中Pt/TiO 2催化剂的活性最高。在室温（20 ℃）下研究了Pt负载量和气时空速（GHSV）对Pt/TiO 2催化剂催化HCHO氧化活性的影响。最佳Pt负载量为1 wt.%。在此负载下，HCHO可以在20 ℃下以50，000 h（-1）的GHSV在Pt/TiO 2上完全氧化为CO2和H2O。采用BET、XRD、高分辨TEM和程序升温还原（TPR）等方法对1%Pt/TiO 2进行了表征。XRD图谱和HR TEM图像显示Pt颗粒在TiO 2上分散良好，尺寸小于1 nm，这是1%Pt/TiO 2高活性的重要特征。利用原位漫反射红外光谱技术研究了甲醛在Pt/TiO 2表面的氧化机理。结果表明，表面甲酸盐和CO物种是甲醛氧化过程中的主要反应中间产物。在没有O-2存在的情况下，甲酸盐物种在催化剂表面分解为吸附的CO物种，然后在O-2存在的情况下，CO被氧化为CO。基于这些结果，提出了1%Pt/TiO 2催化氧化甲醛的简化机理。(c)2006 Elsevier B. V.保留所有权利。
The performance of TiO2 supported noble metal (Pt, Rh, Pd and Au) catalysts was examined and compared for the catalytic oxidation of formaldehyde (HCHO). Among them, the Pt/TiO2 was the most active catalyst. The effects of Pt loading and gas hourly space velocity (GHSV) on Pt/TiO2 activity for HCHO oxidation were investigated at a room temperature (20 degrees C). The optimal Pt loading is 1 wt.%. At this loading, HCHO can be completely oxidized to CO2 and H2O over the Pt/TiO2 in a GHSV of 50,000 h(-1) at 20 degrees C. The 1% Pt/TiO2 was characterized using BET, XRD, high resolution (HR) TEM and temperature programmed reduction (TPR) methods. The XRD patterns and HR TEM image show that Pt particles on TiO2 are well dispersed into a size smaller than 1 nm, an important feature for the high activity of the 1% Pt/TiO2. The mechanism of HCHO oxidation was studied with respect to the behavior of adsorbed species on Pt/TiO2 surface at room temperature using in situ DRIFTS. The results indicate that surface formate and CO species are the main reaction intermediates during the HCHO oxidation. The formate species could decompose into adsorbed CO species on the catalyst surface without the presence Of O-2, and the CO was then oxidized to CO, with the presence of O-2. Based on these results, a simplified mechanism for the catalytic oxidation of HCHO over 1% Pt/TiO2 was proposed. (c) 2006 Elsevier B.V. All rights reserved.