Optimized Synthesis Routes of MnOx-ZrO2 Hybrid Catalysts for Improved Toluene Combustion

Xin Huang,Luming Li,Hongmei Li,Li Lan,Rong Liu,Weiqi Zhou

doi:10.3390/catal11091037

Abstract

In this contribution, the three Mn-Zr catalysts with MnxZr1−xO2 hybrid phase were synthesized by two-step precipitation route (TP), conventional coprecipitation method (CP) and ball milling process (MP). The components, textural and redox properties of the Mn-Zr hybrid catalysts were studied via XRD, BET, XPS, HR-TEM, H2-TPR. Regarding the variation of synthesis routes, the TP and CP routes offer a more obvious advantage in the adjustment of the concentration of MnxZr1−xO2 solid solution compared to the MP process, which directly commands the content of Mn4+ and oxygen vacancy and lattice oxygen, and thereby leads to the enhanced mobility of reactive oxygen species and catalytic activity for toluene combustion. Moreover, the TP-Mn2Zr3 catalyst with the enriched exposure content of 51.4% for the defective (111) lattice plane of MnxZr1−xO2 exhibited higher catalytic activity and thermal stability for toluene oxidation than that of the CP-Mn2Zr3 sample with a value of 49.3%. This new observation will provide a new perspective on the design of bimetal catalysts with a higher VOCs combustion abatement.

Highlights

Volatile organic compounds (VOCs) have been considered important harmful pollutants and can be transferred into secondary aerogel and ozone via complex photochemical reactions in the atmosphere, which are threatening the ecological environment and human health [1,2,3,4]
For the component factor of the active phase, we found that the ratio of Mn/Zr and their synthesis routes play a vital role in adjusting the content of active centers, and a low molar ratio (
A series of Mn-Zr catalysts with different Mn/Zr ratios were successfully prepared via co-precipitation and improved co-precipitation routes, and their catalytic performance for toluene combustion was evaluated

Summary

Introduction

Volatile organic compounds (VOCs) have been considered important harmful pollutants and can be transferred into secondary aerogel and ozone via complex photochemical reactions in the atmosphere, which are threatening the ecological environment and human health [1,2,3,4]. The toluene with toxicity and carcinogenicity is one of the most common VOCs, be discharged from the petrochemical industry, and be normally selected as the target VOCs to test the activity of catalyst. Several techniques, such as adsorption and absorption, thermal incineration, plasma, membrane separation, biological treatment, and catalytic oxidation, have been widely reported for the degradation of VOCs [5]. Catalytic oxidation has been considered one of the most promising technologies because it can completely convert VOCs under relatively low temperatures (

Methods

Discussion

Conclusion