Plasma-Assisted Surface Interactions of Pt/CeO2 Catalyst for Enhanced Toluene Catalytic Oxidation

Bingxu Chen,Limin Chen,Yuhai Sun,Xueqin Wang,Daiqi Ye,Bangfen Wang,Junliang Wu,Yufei Tan,Mingli Fu

doi:10.3390/catal9010002

Abstract

The performance of plasma-modified Pt/CeO2 for toluene catalytic oxidation was investigated. Pt/CeO2 nanorods were prepared by wet impregnation and were modified by thermal (PC-T), plasma (PC-P), and combined (PC-TP and PC-PT) treatments. The modified catalysts were characterized by TEM (transmission electron microscope), BET (Brunauer-Emmett-Teller), H2-TPR, O2-TPD, XPS, UV-Raman, and OSC tests. The significant variation of the surface morphologies and surface oxygen defects could have contributed to the modification of the Pt/CeO2 catalysts via the plasma treatment. It was found that plasma could promote the surface interaction between Pt and CeO2, resulting in the thermal stability of the catalyst. The Pt-Ce interaction was also conducive to an increase in the number of oxygen vacancies. Furthermore, PC-PT and PC-TP showed a significant difference in oxygen vacancy concentrations and catalytic activities, which illustrated that the treatment sequence (plasma and thermal treatment) affected the performance of Pt/CeO2. The PC-PT sample showed the highest catalytic activity with T100 at 205 °C. This work thus demonstrates that plasma in combined treatment sequences could assist surface interactions of catalysts for enhanced toluene catalytic oxidation.

Highlights

Volatile organic compounds (VOCs) are high-risk contaminants, which can cause a significant threat to the nervous system and the environment [1,2]
T100 and T50 were found for PC-PT at 205 ◦ C and 167 ◦ C, respectively, while the T100 of PC-TP was 236 ◦ C, 30 ◦ C higher than that of PC-PT
From the results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and H2-TPR, it was concluded that plasma played a vital role in promoting the surface interaction

Summary

Introduction

Volatile organic compounds (VOCs) are high-risk contaminants, which can cause a significant threat to the nervous system and the environment [1,2]. Toluene is a representative VOC, which is of high toxicity and very difficult to naturally degrade. In the past few years, the use of noble metals (Pt, Au, Pd) and redox supports (CeO2 , Co3 O4 , ZrO2 ) [3,4,5,6] to improve toluene oxidation has been prevalent. The CeO2 redox support has attracted considerable attention due to its high oxygen storage ability. During the traditional preparation of these catalysts, calcination is employed to activate the catalyst, but they are at risk of sintering at high temperatures. To avoid this risk during Pt/CeO2 activation, non-thermal plasma has been proposed as an alternative technique

Methods

Results

Discussion

Conclusion