Quantitative Kinetic Insights from Operando-UV/Vis Spectroscopy: An Application to NH-SCR of NOx on Cu-CHA Catalysts.

We employ UV/Vis Diffuse Reflectance spectroscopy directly coupled with a packed bed flow reactor to extract quantitative kinetic information. We use as a show-case the Cu/Cu redox dynamics during the reduction half cycle of the NH-Selective Catalytic Reduction (SCR) on Cu-CHA catalysts. Our measurements enable quantification of the fraction of oxidized Cu, reconstructed by Multivariate Curve Resolution (MCR) together with monitoring of the gas-phase evolution during the reaction.

Electrified methane steam reforming on a washcoated SiSiC foam for low-carbon hydrogen production.

In view of largely available renewable electricity as a green future resource, here we report the electrification of a Rh/AlO washcoated SiSiC foam for methane steam reforming (MSR). We show that, thanks to the suitable bulk resistivity of the SiSiC foam, its direct Joule heating up to relevant temperatures is feasible; the interconnected geometry greatly reduces heat and mass transfer limitations, which results in a highly active and energy efficient system for low-carbon H production. The foam-based electrified MSR (eMSR) system showed almost full methane conversion above 700°C and methane conversions approaching equilibrium were obtained in a range of conditions.

Appraising Multinuclear Cu Structure Formation in Cu-CHA SCR Catalysts via Low-T Dry CO Oxidation with Modulated NH Solvation.

Cu ions (ZCu (OH) , Z Cu ) are regarded as the NH -SCR (SCR=selective catalytic reduction) active site precursors of Cu-exchanged chabazite (CHA) which is among the best available catalysts for the abatement of NO from Diesel engines. During SCR operation, copper sites undergo reduction (Reduction half-cycle, RHC: Cu →Cu ) and oxidation (Oxidaton half-cycle, OHC: Cu →Cu ) semi cycles, whose associated mechanisms are still debated. We recently proposed CO oxidation to CO as an effective method to probe the formation of multinuclear Cu species as the initial low-T RHC step.

A Fundamental Investigation of Gas/Solid Heat and Mass Transfer in Structured Catalysts Based on Periodic Open Cellular Structures (POCS).

In this work, we investigate the gas-solid heat and mass transfer in catalytically activated periodic open cellular structures, which are considered a promising solution for intensification of catalytic processes limited by external transport, aiming at the derivation of suitable correlations. Computational fluid dynamics is employed to investigate the Tetrakaidekahedral and Diamond lattice structures. The influence of the morphological features and flow conditions on the external transport properties is assessed.

On the Redox Mechanism of Low-Temperature NH -SCR over Cu-CHA: A Combined Experimental and Theoretical Study of the Reduction Half Cycle.

Cu-CHA is the state-of-the-art catalyst for the Selective Catalytic Reduction (SCR) of NOx in vehicle applications. Although extensively studied, diverse mechanistic proposals still stand in terms of the nature of active Cu-ions and reaction pathways in SCR working conditions. Herein we address the redox mechanism underlying Low-Temperature (LT) SCR on Cu-CHA by an integration of chemical-trapping techniques, transient-response methods, operando UV/Vis-NIR spectroscopy with modelling tools based on transient kinetic analysis and density functional theory calculations.