Performance and reaction mechanism of zeolite-supported Cu-based catalysts for removing CH 3 OH from flue gas

Methanol is increasingly adopted as a clean alternative fuel in the shipping industry. However, incomplete combustion releases harmful emissions such as unburned CH ₃ OH, necessitating effective aftertreatment technologies. Selective catalytic oxidation (SCO) of methanol (CH ₃ OH) represents a promising solution, where the development of high-performance catalysts is critical for commercial implementation. In this study, a series of zeolite-supported Cu-based catalysts were prepared via impregnation and evaluated for their methanol oxidation activity in the temperature range of 150-450 ℃. Among them, Cu/ZSM-5 catalyst exhibited excellent catalytic performance, achieving 90% methanol conversion at 189 ℃ and maintaining complete conversion over a wide temperature range (240-450 ℃) without detectable by-products. The characterization results revealed that the high activity of Cu/ZSM-5 was attributed to its high percentage of Cu ²⁺ species, abundance of surface-adsorbed oxygen and weak basic sites. In-situ DRIFTS identified formic acid as a possible key reaction intermediate and elucidated temperature-dependent reaction pathways. This work demonstrates the potential of Cu/ZSM-5 as a cost-effective catalyst for methanol oxidation, contributing to the development of sustainable emission control technologies.