Simultaneous observation of gas phase and surface species in photocatalytic reactions: The next generation of DRIFTS applications

We have developed the new generation of photocatalytic testing to observe the gas-phase photocatalytic reactions in situ. It is based on modified Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) unit equipped with smart collector system. We have employed UV diode coupled with fibre optics to illuminate the sample while simultaneous collecting the diffuse reflectance spectra. This method was applied to study the NO₂ photocatalytic conversion on gold modified TiO₂ samples. We have successfully demonstrated that both gas phase and surface adsorbed species can be identified and used to compare the activity of various catalysts. We have found that gold nanoparticles have significantly increased the activity of the catalysts for both gas phase and liquid phase oxidation.