The Basis for Photocatalytic Writing

Abstract

We present a demonstration involving the oxidative photobleaching of a raspberry juice dye under visible laser light irradiation using the semiconductor titanium dioxide. A plausible interpretation of the phenomenon is discussed that aids in the understanding of semiconductor energetics and the nature of light.

Teaching Photochemistry: Experimental Approaches and Digital Media

“…Depending on the light source, it comes to a visible degradation of the dye, yielding in lower voltages within a school lesson. In fact, TiO 2 is a photocatalyst and promotes the photodegradation of anthocyanin dyes [4] . After a few irradiation cycles an anthocyanin‐sensitized photoelectrode is obviously bleached by degradation of the dye.…”

“…We have profitably used the negative aspect of the rapid photobleaching of the anthocyanin‐sensitized TiO 2 photoelectrodes (see section above) to develop experiments on the photocatalytic oxidation of organic compounds [4] . In order to prepare a thin layer of dye‐sensitized photocatalytic TiO 2 , we have brushed a slurry of nanocrystalline TiO 2 (anatase) on pieces of regular laboratory filter paper.…”

“…In this sense, we have been exploring experimental approaches and developing teaching materials for more than 20 years [2–13] . Some of them have been presented in about ten editions of the Central European Photochemistry Conference CECP in Bad Hofgastein (Austria), and most of our experiments and teaching materials have been digitalized and made available in German and English as open access on our website [14] .…”

Demonstrating Online Monitoring of Air Pollutant Photodegradation in a 3D Printed Gas-Phase Photocatalysis Reactor

“…A visible color change of the solution is observed within 5 to 30 min, which can readily be quantified spectrophotometrically. 29 In contrast, tutorial demonstration of gas phase photocatalysis for educational purposes is more challenging and, as there is no visible change, advanced analytical equipment such as gas chromatography (GC), mass spectrometry (MS), GC−MS, or advanced IR spectroscopy setups is required, 30 which complicates online (in situ) analysis.…”

Using Photocatalytic Oxidation and Analytic Techniques To Remediate Lab Wastewater Containing Methanol

“…Facing the urgent need for new technologies to contain increasing environmental degradation, chemical educators have introduced to students the theory and application of semiconductor photocatalysis, in particular, the TiO 2 -mediated system, which is thought to be economically and environmentally benign. − In this Journal , there are many reports of teaching experiments dedicated to help students gain insight into the chemistry of photocatalysis. − Tatarko et al introduced an inexpensive photocatalytic reactor, using a glass beaker and long durable fluorescent lamp, to illustrate the remediation of azo dye in water . Herrera-Melina et al reported the photocatalytic remediation of lab wastewater containing p -nitrophenol, which was referred to as a pedagogical use of lab waste .…”