PEPICO analysis of catalytic reactor effluents at the FinEstBeaMS beamline of MAX IV Laboratory: DME conversion over a ZSM-5 zeolite

The Methanol-To-Hydrocarbons (MTH) process involves the conversion of methanol, a C1 feedstock that can be produced from green sources, into hydrocarbons using acid zeolite or zeotype catalysts (Olsbye et al., 2012). The reaction that occurs in zeolites yields a complex mixture of multiple isomers and species, which poses challenges for effluent analysis. The conventional gas-phase chromatography (GC) method, typically employed for effluent analysis (Hemberger et al., 2020), is often insufficient for separating isomers or detecting highly reactive molecules, especially with increased time resolution. As a potential solution, here, photoelectron-photoion coincidence (PEPICO) analysis of dimethyl ether (DME) flown through a zeolite catalyst (ZSM-5) has been performed at the FinEstBeAMS beamline of the MAX IV. Even-though, due to the specific configuration of the reactor packing, highly-reactive intermediates are not detected, the ratio of xylene isomers in the product stream is quantitatively determined by deconvoluting the coincidence photoelectron spectra.