In situ pyrolysis of Mn-doped MOF-74 metal–organic framework derived MCNOx catalysts for enhanced low-temperature catalytic performance of toluene

Abstract

This paper focuses on the use of catalysts generated from metal–organic frameworks (MOFs) for the degradation of toluene in a linked non-thermal plasma/photocatalytic process. The porous tri-metal oxide catalyst (MCNOx) was derived from the metal organic framework (MOF-74) via an in situ pyrolysis strategy utilizing Mn-doped CoNi-MOF-74 as the precursor. The resulting MCNOx material exhibits a unique series of surface defects, which significantly enhances its catalytic activity. We found that MCNOx materials, due to their high specific surface area, regular porous structure, and excellent reducibility, can synergize well with NTP in the complete decomposition of toluene, which makes the NTP coupled catalytic system have better catalytic activity and CO₂ selectivity. The toluene conversion temperature of T90 in the NTP synergistic thermocatalytic system was 250 °C for the 5MCNOx catalyst, which was also much higher than that of 1MCNOx (256 °C), 10MCNOx (258 °C), CNOx (270 °C), and 5MCNOx catalyst in the monocatalytic system (270 °C). In addition, the catalytic stability of MOF-derived MCNOx oxides and the influence of water vapor on catalytic activity were investigated, confirming their excellent catalytic performance. Finally, the importance of Mn doping in improving toluene oxidation activity on MOF-74 derived CNOx has been demonstrated, providing a viable strategy for developing a toluene oxidation catalyst.