Efficient and stable low-temperature CO oxidation over Pt/In–SnO2 composite triggered by abundant oxygen vacancies and adsorption sites

Abstract

It is of great significance to design highly active and stable catalysts for CO oxidation. Herein, a Pt/In–SnO₂ catalyst was firstly fabricated via a facile hydrothermal reaction coupled with photoreduction strategy, achieving 1 vol% of CO totally oxidized at just 145 °C, over 200 °C lower than that of Pt/SnO₂. Moreover, Pt/In–SnO₂ demonstrates superior catalytic stability and recyclability under both dry and humid conditions. Incorporation of In cations results in marked structure distortion of SnO₂, promoting the formation of oxygen vacancies and enhancing the concentration and mobility of reactive oxygen species. Abundant Pt sites over Pt/In–SnO₂ further accelerate CO adsorption and activation. Density functional theory results prove that the energy barrier of CO oxidation reduces from 0.85 to 0.75 eV after In doping and the produced CO₂ can desorb spontaneously from the catalyst surface, which accelerates the CO oxidation process. This work provides new ideas for designing robust catalysts for low-temperature CO elimination.