ZSM-5 surface modification by plasma for catalytic activity improvement in the gas phase methanol-to-dimethylether reaction

Abstract

Abstract Dimethylether (DME) is nowadays considered as one of the most promising alternative fuels for the future. It has a very low climate impact, and can be produced in a renewable way, namely from the gas phase condensation of methanol over common acid catalysts such as γ-Al2O3 or zeolites. The challenge today is to switch from high reaction temperatures (300–350 °C) to lower ones (ideally 100–150 °C) in order to operate more energy-efficiently and with 100% selectivity to DMEThe methanol conversion needs to be increased below 300 °C in order to get high yields of DME even in that low temperature range. In the present paper, we show a way to achieve this in the case of the widely studied ZSM-5 zeolite. We show that submitting the zeolite to a cold plasma treatment before using it as a catalyst allows significantly increasing the yield of DME up to 300 °C. Indeed, the plasma treatment leads to a partial dealumination of the zeolite and thereby to an increase of the number of strong Bronsted acid sites which play a key role in the methanol-to-DME reaction mechanism.