Lithographically fabricated silicon microreactor for operando QEXAFS studies in exhaust gas catalysis during simulation of a standard driving cycle

摘要

Selective catalytic reduction of NO_x by ammonia over Cu-ZSM-5 was monitored by operando QEXAFS during simulation of the New European Driving Cycle. The required fast temperature transients were realized using a novel silicon microreactor, enabling simultaneous spectroscopic and kinetic analysis by X-ray absorption spectroscopy (XAS) and mass spectrometry (MS). Periods of high temperature were correlated to an increase in both N_2 production and change of coordination of Cu sites. This operando approach using Si microreactors can be applied to other heterogeneous catalytic systems involving fast temperature transients.