Operando Shell‐Isolated Nanoparticle‐Enhanced Raman Spectroscopy of the NO Reduction Reaction over Rhodium‐Based Catalysts

Abstract

Operando shell‐isolated nanoparticle‐enhanced Raman spectroscopy (SHINERS) with on‐line mass spectrometry (MS) has been used to investigate the surface species, such as NO, NOH, NO2, N2O, and reaction products of the NO reduction reaction with CO and H2 over supported Rh‐based catalysts in the form of catalyst extrudates. By correlating surface intermediates and reaction products, new insights in the reaction mechanism could be obtained. Upon applying different reaction conditions (i. e., H2 or CO), the selectivity of the catalytic reaction could be tuned towards the formation of N2. Furthermore, in the absence of Rh, no reaction products were detected. The importance of the operando SHINERS as a surface‐sensitive characterization technique in the field of heterogeneous catalysis provides routes towards a better understanding of catalytic performance.

The state-of-the-art in the electroreduction of NOx for the production of ammonia in aqueous and nonaqueous media at ambient conditions: a review

“…In aqueous solution, operando SHINERS is similarly exploited in NORR for the study of intermediates as well as product formation on the catalyst surface. 135 Even though ILs exhibit good NO x adsorption and reduction ability, there is a lack of a basic understanding of the intermediates that form and how they influence product selectivity. Furthermore, the mechanism of interaction between the reactive species and catalyst surface also requires to be fully supplemented.…”

“…Furthermore, the mechanism of interaction between the reactive species and catalyst surface also requires to be fully supplemented. 135 At present, the in-depth study and improvement of the mechanism of NORR in ILs is still challenging. On the one hand, as electrolytes, ILs can improve the product selectivity of NORR, but none of the rational reaction mechanisms in ILs has been presented on a small scale.…”