Effect of Pd/Ce Loading and Catalyst Components on the Catalytic Abatement of Toluene

Wenjun Liang,Xiujuan Shi,Guobin Yin,Qinglei Li,Sida Ren

doi:10.3390/catal12020225

Wenjun Liang, Xiujuan Shi + Show 3 more

Open Access

https://doi.org/10.3390/catal12020225

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Abstract

Monolithic catalysts are widely used in industrial catalysis. However, in the preparation of a monolithic catalyst, the traditional methods have some drawbacks such as low washcoat uploading ratio and poor uniformity. In the present work, the effects of Pd/Ce loading and catalyst components on the catalytic abatement of toluene were investigated. The acid treatment of the substrate, the particle size of the slurry and the dispersant on the uniformity of the washcoat and the catalytic performance were also explored. Characterisation was achieved via BET, SEM, zeta potential and laser grain-size analyses. The results showed that the catalytic activity of the catalyst increased with the increasing of the Ce content. It was found that the 0.2Pd-0.3Ce/γ-Al2O3 catalysts had the best toluene catalytic activity. The pretreatment of the cordierite with 20% HCl could improve the properties of the cordierite. It was also found that reducing the particle size of the washcoat and adding dispersant PAA could effectively improve the stability of the suspension and the uniformity of the washcoat. When 20% HCl pretreatment was used, the toluene catalytic activity of the monolith catalyst prepared by cordierite increased, in which T10 and T90 decreased by about 5 °C. Decreasing the particle size and dispersant also promoted the efficiency of catalytic degradation.

Highlights

The rapid development of industry has complicated the types of Volatile Organic Compounds (VOCs) emitted [1]
With the addition of a small amount of the rare earth element Ce, the catalytic activity of the catalyst increased with the increasing of the Ce content
When the content of CeO2 was 0.3 wt%, the T10 was lower than 150 ◦C, which greatly strengthened the catalytic activity of the catalyst in the low-temperature region

Summary

Introduction

The rapid development of industry has complicated the types of Volatile Organic Compounds (VOCs) emitted [1]. To obtain a larger specific surface area, commonly used methods include: (1) preparation of a washcoat by loading a carrier with a high specific surface area on the surface of the substrate [13,14,15,16]; (2) acid treatment of the cordierite surface [17,18,19]. Lu [22] and Sun [23] used different concentrations of nitric acid for acid pretreatment of the carrier, which improved the specific surface area of the carrier and increased the loading ratio of the coating, improving the catalytic performance of the monolithic catalyst. It is necessary to systematically study the pretreatment of the monolithic catalyst carrier and the dispersion performance of the catalyst slurry to prepare monolith catalysts with uniform washcoats and high catalytic efficiencies. This paper covers research conducted on the determination of the powder catalyst formula and the optimization of the monolithic catalyst preparation process in a systematic manner; the results of our work will help to solve the bottleneck problem in the preparation of monolithic catalysts and the practical engineering application of monolithic catalysts

Results and Discussion

Catalytic Combustion Performance of the Monolithic Catalyst

Effect of Particle Size of the Washcoat on the Performance of the Catalyst

Effect of Dispersant on the Performance of the Catalyst

Conclusions