SO2-tolerant mesoporous iron oxide supported bimetallic single atom catalyst for methanol removal

Abstract

Among the single-atom catalysts (SACs), the bimetallic single-atom catalysts play an increasingly promising role in the oxidative removal of volatile organic compounds (VOCs) due to their high efficiency. However, it remains a significant challenge to resist SO2 poisoning in industrial applications. In this work, we report (i) the synthesis of three-dimensionally ordered mesoporous Fe2O3-supported bimetallic AuPt single-atom (denote as Au1Pt1/meso-Fe2O3) catalyst via a modified polyvinyl alcohol-protected reduction route; (ii) catalytic performance of the catalysts for methanol oxidation; and (iii) catalytic and SO2-resistant mechanism. It was found that compared with Pt1/meso-Fe2O3 and Ptnp/meso-Fe2O3, Au1Pt1/meso-Fe2O3 exhibited better catalytic activity for methanol combustion, with the temperature at 90% methanol conversion, TOFnoble metal at 120 °C, and apparent activation energy being 137 °C at a space velocity of 20 000 mL g–1 h–1, 6.51 × 10–2 s–1, and 36 kJ mol− 1, respectively. The enhanced activity was associated with the improved reducibility, methanol adsorption ability, and strong interaction between noble metal and support. The reaction pathway was deduced to follow a sequence of methanol → methoxy species → formaldehyde → formic acid → CO2 and H2O. Furthermore, the order of SO2 resistance was Au1Pt1/meso-Fe2O3 > Pt1/meso-Fe2O3 > Ptnp/meso-Fe2O3. The good SO2 resistance of the Au1Pt1/meso-Fe2O3 catalyst was attributed to the Au−Pt bimetallic single atoms uniformly dispersed on the meso-Fe2O3 with the strong ability of sulfate decomposition and the protection of the active sites by meso-Fe2O3 as a sacrificial site. This work presents a novel way for developing high-performance catalysts for VOCs elimination in the presence of SO2.