Effects of the Reaction Parameters and Light Hydrothermal Aging for Catalytic Combustion of Propane over Co-Mn-Ce Catalyst

Lili Lei,Chenrui Cui,Miaomiao Jin,Kai Li,Pan Wang,Ajaya Kumar Singh

doi:10.1155/2022/4574887

Abstract

A composite oxides’ Co-Mn-Ce catalyst was synthesized by a coprecipitation method, and the experiment was carried out to study the effects of reaction parameters and light hydrothermal aging on propane combustion over the Co-Mn-Ce catalyst. The influence of reaction temperature, propane concentration, oxygen concentration, water vapor, and hydrothermal aging was studied during the catalytic combustion of propane. The propane conversion significantly decreased by 10% when the propane concentration increased at 300°C and then further decreased from 80% to 40% as water vapor concentration increased from 0 to 10 vol.%. In addition, water vapor also prolonged the time required to reach equilibrium. After hydrothermal treatment, the catalyst obtained the lowest oxidation capacity of propane. Furthermore, the results of in situ DRIFTs and O2 temperature programmed desorption (O2-TPD) demonstrated that there were fewer oxygen species after hydrothermal aging, and carbonates were the main intermediates formed during the catalytic oxidation of propane.

Highlights

Volatile organic compounds (VOCs) are atmospheric pollutants emitted from a wide range of industrial processes and motor vehicle fuel combustion and cause chemical smog, haze, and ozone generation [1,2,3]
The outlet propane concentration reached 900 × 10−6 v/v without water at 200°C, and this temperature corresponded to a propane conversion of 10%, which indicated that CMC presented a good low-temperature catalytic activity. e propane concentration was 30 × 10−6 v/v at 350°C, and the propane conversion was 97%
The effects of various reaction conditions were investigated over CMC catalysts by propane oxidation experiments. e catalytic oxidation experiments indicated that propane conversion was significantly different at 300°C under various water vapor concentrations

Summary

Introduction

Volatile organic compounds (VOCs) are atmospheric pollutants emitted from a wide range of industrial processes and motor vehicle fuel combustion and cause chemical smog, haze, and ozone generation [1,2,3]. Catalytic oxidation is considered an effective method for VOCs degradation due to its low operating temperature range (300–600°C) and because it does not require additional fuel and produces less secondary pollution than thermal oxidation [4, 5]. Among transition metals, mixed oxides show synergistic effects that produce catalytic activities than single-metal oxides. A strong synergistic effect of Mn-Co species in the oxide made a great contribution to its low-temperature reducibility which played a key role in VOCs oxidation. Deng et al [21] found out that a solid solution was formed with more active oxygen induced by Co doping, while strong interaction effects among Co-Mn-Ce-O were speculated as the main mechanisms underlying the high efficiency catalytic capacity. Kan et al [23] reported that Mn8Co1Ce1/cordierite presented the best activity and stability among all of the catalysts synthesized. e results were attributed to the synergistic effect of ceria, manganese, and cobalt, which could promote the formation of more lattice defects, more oxygen vacancies, and smaller crystallite sizes

Methods

Results

Conclusion