Nitrogen Monoxide and Soot Oxidation in Diesel Emissions with Platinum–Tungsten/Titanium Dioxide Catalysts: Tungsten Loading Effect

Duck-kyu Oh,Young-Jae Lee,Jong-Soo Park,Kwan-Young Lee

doi:10.3390/catal10111283

Abstract

Compared with Pt/TiO2, tungsten-loaded Pt–W/TiO2 catalysts exhibit improved activity for NO and soot oxidation. Using catalysts prepared by an incipient wetness method, the tungsten loading effect was investigated using Brunauer–Emmett–Teller surface areas, X-ray diffraction, transmission electron microscopy (TEM), CO pulse chemisorption, H2 temperature-programmed reduction, NH3 temperature-programmed desorption (NH3-TPD), and pyridine Fourier transform infrared (FT-IR) spectroscopy. Loading tungsten on the Pt/TiO2 catalyst reduced the platinum particle size, as revealed in TEM images. CO pulse chemisorption showed that platinum was covered with tungsten and the dispersion of platinum decreased when 5 wt.% or more of tungsten was loaded. The NH3-TPD and pyridine-FT-IR results demonstrated that the number of strong acid sites and Brønsted acid sites in the catalyst were increased by the presence of tungsten. Therefore, a catalyst containing an appropriate amount of tungsten increased the dispersion of platinum, thereby increasing the number of active sites for NO and soot oxidation, and increased the acidity of the catalyst, thereby increasing the activity of soot oxidation by NO2

Highlights

Harmful exhaust emissions regulations have been tightened owing to the increasing use of diesel engines in various fields, such as coal-fired power plants, ships, aviation, and automobiles [1,2].Exhaust emissions from diesel engines include hydrocarbons, soot, NOx, SOx, and carbon monoxide.Among these emissions, soot, which consists of unburned carbon particles, can cause air pollution, various respiratory diseases, and lung cancer
We investigated the effect of the tungsten content in a Pt/TiO2 catalyst on the soot oxidation characteristics at low exhaust gas temperatures
The catalyst loaded with 3 wt.% tungsten showed the highest activity for soot oxidation using NO

Summary

Introduction

Harmful exhaust emissions regulations have been tightened owing to the increasing use of diesel engines in various fields, such as coal-fired power plants, ships, aviation, and automobiles [1,2].Exhaust emissions from diesel engines include hydrocarbons, soot, NOx, SOx, and carbon monoxide.Among these emissions, soot, which consists of unburned carbon particles, can cause air pollution, various respiratory diseases, and lung cancer. Harmful exhaust emissions regulations have been tightened owing to the increasing use of diesel engines in various fields, such as coal-fired power plants, ships, aviation, and automobiles [1,2]. Exhaust emissions from diesel engines include hydrocarbons, soot, NOx, SOx, and carbon monoxide. Among these emissions, soot, which consists of unburned carbon particles, can cause air pollution, various respiratory diseases, and lung cancer. Union (EU) introduced the EURO emission regulation in 1994 as a means to reduce the emission of pollutants in the exhaust gas of diesel cars. EURO-6c was introduced in September 2017, which applies the Worldwide Harmonized Light Vehicle Test Procedure (WLTP) and Real Driving Emissions (RDE)

Methods

Results

Conclusion