In Situ FTIR Reactor for Monitoring Gas-Phase Products during a (Photo)catalytic Reaction in the Liquid Phase

Abstract

Various catalytic and photocatalytic reactions in the liquid phase give rise to gas products. Therefore, the identification and quantification of these products are of high importance and even essential for some reactions. In this communication, a new in situ FTIR reactor is designed and used for analyzing the gas headspace of a (photo)catalytic reaction in solution. It allows the identification and quantification of the gas products of a liquid reaction under operating conditions and in real time. The new reactor has been tested in three representative photocatalytic reactions widely studied as model reactions in the liquid phase, i.e., i) decomposition of formic acid, ii) oxidation of Methylene Blue and iii) reduction of CO2. The validity of the results has been confirmed by analyzing the headspace at the end of the reaction using GC. The new reactor opens the possibility to follow on-line the (photo)catalyst activity. This is useful for ensuring the stability of the catalyst and studying the evolution of the selectivity during the reaction. The nondestructive behavior of the FTIR technique allows its coupling with other techniques for obtaining complementary results. The new reactor setup is easy to handle, to ship, and is very efficient which make it very suitable for performing fast and/or preliminary studies.

Rhenium-functionalized covalent organic framework photocatalyst for efficient CO2 reduction under visible light

“…The photocatalytic CO2 reduction was tested in a new in-situ reactor developed recently in the LCS laboratory and presented in Scheme 1 [28]. The reactor is made from glass and equipped with two gas inlet and outlet, perpendicular to the tubes ensuring the FTIR beam pathway through CaF2 windows.…”

“…The CO2 photoreduction was performed using a new in situ FTIR reactor (in a batch mode) as described in the experimental section. The photocatalysts have been tested under similar reaction condition used in the literature [28]. Re-TpBpy, Re-Bpy and TpBpy compounds were first dispersed in acetonitrile and water solution contained triethanolamine (TEOA) as electron donor.…”

“…(a) The in-situ FTIR reactor and (b) the entire setup used for performing the photocatalytic tests: (1) in-situ FTIR reactor; (2) optical fiber guide light; (3) light source; (4) gas flow setup (for purge); (5) magnetic stirrersteerer; (6) FTIR spectrometer. More details on the setup can be found in a recent reference[28].…”

In situ and Operando Spectroscopies in Photocatalysis: Powerful Techniques for a Better Understanding of the Performance and the Reaction Mechanism

“…A new in-situ home-made glass reactor equipped with CaF2 windows has been developed by El-roz et al (Fig. 5A) for monitoring homogeneous and heterogeneous photocatalytic reactions in liquid phase [33]. The new insitu FTIR reactor is dedicated for a real-time analysis of the gas products in transmission mode, but it cannot provide information on the evolution of catalyst surface during the reaction.…”

“…This reactor solves the problems of i) irradiation homogeneity, ii) solvent condensation, iii) deformation of O-ring in presence of an organic solvent and iv) seal's ability of the reactor to control leaks, which is very important for air-sensitive reaction. The in-situ reactor was used to study different kinds of photocatalytic reactions in liquid phase such as formic acid decomposition [33], the photocatalytic CO2 reduction [34,35] and the photodegradation of Methylene Blue (MB) [33]. This latter was performed on TiO2 P25 under monochromatic irradiation at 365 nm.…”