CAJ | 학술논문

利用沉积沉淀法制备了Pt/TiO2催化剂,将其在不同温度下焙烧,以得到不同颗粒尺寸的Pt.并将这些样品用于CO催化氧化反应以及反应动力学研究.结果表明:焙烧温度对催化剂有明显影响, Pt颗粒尺寸随着焙烧温度的升高而增加;与此同时, CO催化活性随焙烧温度的升高呈先增加后降低的趋势,其中,400°C焙烧的样品表现出最高的催化活性.反应动力学结果表明,催化剂上CO氧化反应表观速率方程为r=5.4×10-7p0.17CO p0.36O 2,说明在该催化剂上CO氧化遵循Langmuir-Hinshelwood机理.同时,对催化剂进行了CO化学吸附红外光谱和O2化学吸附表征.结果表明,随着焙烧温度的升高,催化剂上CO和O2吸附量均呈现先升高后降低的趋势,这与反应结果和反应动力学方程一致,说明反应受到催化剂表面上CO和O2吸附浓度的影响.而在400°C焙烧的催化剂上, CO和O2吸附量均最高,因此其反应活性也最好.这可能是焙烧过程影响了Pt和TiO2之间的相互作用引起的.
이용침적침정법제비료Pt/TiO2최화제,장기재불동온도하배소,이득도불동과립척촌적Pt.병장저사양품용우CO최화양화반응이급반응동역학연구.결과표명:배소온도대최화제유명현영향, Pt과립척촌수착배소온도적승고이증가;여차동시, CO최화활성수배소온도적승고정선증가후강저적추세,기중,400°C배소적양품표현출최고적최화활성.반응동역학결과표명,최화제상CO양화반응표관속솔방정위r=5.4×10-7p0.17CO p0.36O 2,설명재해최화제상CO양화준순Langmuir-Hinshelwood궤리.동시,대최화제진행료CO화학흡부홍외광보화O2화학흡부표정.결과표명,수착배소온도적승고,최화제상CO화O2흡부량균정현선승고후강저적추세,저여반응결과화반응동역학방정일치,설명반응수도최화제표면상CO화O2흡부농도적영향.이재400°C배소적최화제상, CO화O2흡부량균최고,인차기반응활성야최호.저가능시배소과정영향료Pt화TiO2지간적상호작용인기적.
A series of Pt/TiO2 catalysts were prepared using a deposition-precipitation method and calcined at different temperatures to obtain various Pt particle sizes. The catalysts were tested for catalytic CO oxidation and the kinetics of the reaction was studied. The results showed that the Pt particle size increased with calcination temperature, and that their reactivity for CO oxidation first increased and then decreased with increasing calcination temperature, with the catalyst calcined at 400 °C possessing the highest reactivity. The kinetic investigation revealed that the reaction rate could be described by r=5.4×10-7p0.17CO p0.36O 2 , suggesting that the reaction fol owed a Langmuir-Hinshelwood mechanism. Meanwhile, O2 chemisorption and infrared (IR) spectroscopy of CO chemisorption on the catalysts were conducted to reveal the relationship between the catalyst structure and its catalytic behavior. It was found that the amount of O2 chemisorption and the intensity of CO chemisorption by IR on the catalysts first increased and then decreased with increasing calcination temperature, which was consistent with the catalytic results and the kinetic equation. This could explain the catalytic behaviors of the catalysts. For example, the highest amounts of chemisorbed O2 and CO were obtained over the Pt/TiO2 calcined at 400 °C, which resulted in the highest reactivity. Such an enhancement in reactivity was probably due to the strong interaction between Pt and TiO2 induced by the calcination process.