Low-Temperature Total Oxidation of Propane Using Silver-Decorated MnO₂ Nanorods

Abstract

The interaction between active metal centers and supports can be tailored by the judicious combination of morphologically specific metal nanoparticles and metal oxide supports such that the efficacy of the catalysts could be enhanced for practical suitability. Herein, structurally engineered spherical silver nanoparticles (AgNPs) were decorated on manganese oxide nanorods (MnO2NRs), and their catalytic efficacy toward complete oxidation of propane has been explored. It was observed that 1 wt % Ag-loaded catalysts (1Ag/MnO2NRs) exhibited the highest catalytic activity, where the temperatures required for the oxidation of 10% (T 10%), 50% (T 50%), and 90% (T 90%) of propane were 130, 160, and 190 °C, respectively, with apparent activation energy as low as 42.73 kJ mol–1. Strong metal–support interaction between AgNPs and MnO2NRs leads to an increase in the oxygen vacancies and activation of surface oxygen. A series of investigations including X-ray photoelectron spectroscopy, temperature-programmed desorption by oxygen, temperature-programmed reduction by hydrogen, and in situ DRIFTS were carried out in an effort to establish the mechanistic pathway, and it could be concluded that the 1Ag/MnO2NR has substantiated impressive catalytic activity through Mars–van–Krevelen mechanism. Furthermore, 1Ag/MnO2NR has demonstrated remarkable activity and stability when compared with the current benchmark catalysts and thus can be considered as a proficient catalyst toward total oxidation of propane from industrial exhausts.