Silicon microfabricated reactor for operando XAS/DRIFTS studies of heterogeneous catalytic reactions

B Venezia,G Sankar,E Cao,C R A Catlow,S K Matam,E K Gibson,S Golunski,I Silverwood,G Cibin,A Gavriilidis,C Waldron,P P Wells

doi:10.1039/d0cy01608j

Abstract

A novel microreactor for operando XAS and DRIFTS studies of catalytic reactions is reported, exhibiting plug-flow, isothermal behaviour and absence of mass transfer resistances and dead volume, enabling time- and spatially-resolved experiments.

Highlights

We have developed a novel silicon-glass plug-flow microreactor operating under no external and internal mass transfer resistances, suitable for operando X-ray absorption spectroscopy (XAS), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and mass spectrometry (MS) studies
The applicability and versatility of the microreactor for operando XAS and DRIFTS studies is demonstrated in the catalytic combustion of methane and carbon monoxide oxidation
Operando XAS at the Pd K-edge conducted in transmission mode during methane combustion over Pd/Al2O3 showed that the palladium was in oxidised state at all studied temperatures at the inlet of the catalyst bed

Summary

Introduction

The relationship between catalyst structure, activity and product selectivity for a given reaction has been extensively studied to design and develop catalytic processes.[1,2,3,4] Catalyst structure and activity relationships can be explored using a variety of spectroscopic and microscopic techniques and combination of two or more spectroscopic methods in a single reactor can offer complementary information.[2,4] X-ray absorption spectroscopy (XAS) is an element-specific technique, which provides information on the geometric, electronic and chemical state of an atom in the catalyst.[1,5,6,7,8,9] One of the most commonly used techniques to study catalysts is infrared (IR) spectroscopy, which interrogates the vibrational state of the catalyst and the adsorbed molecules on the catalyst surface, providing useful information on the reaction and deactivation mechanisms.[10,11] In particular, 7842 | Catal.

Methods

Results

Conclusion