Differences between Zn-porphyrin-coupled titanate nanotubes with various anchoring modes: Thermostability, spectroscopic, photocatalytic and photoelectronic properties

In order to study the effects of anchoring modes on the properties of porphyrin zinc (ZnP) coupled titanate nanotubes (TNTs), the TNTs coupled with 5,10,15,20-tetraphenylporphyrin zinc (ZnTPP) and 5-(4-hydroxyphenyl)10,15,20-triphenylporphyrin zinc (ZnMOHPP), which were denoted as TNTs–ZnTPP and TNTs–ZnMOHPP, were prepared using a simple refluxing method, respectively. Based on the different experimental phenomena observed during the synthesis process as well as the results of the spectral characterization, thermogravimetric analysis, photocatalysis test and photoelectrochemistry measurement, it was demonstrated that the ZnMOHPP molecules were bonded mainly on the outer surfaces of the TNTs through hydrogen bonds, while the ZnTPP molecules were physically adsorbed into the pore channels of the TNTs via a capillary process. The different anchoring modes of ZnP on the TNTs as well as the special morphology of TNTs resulted in the remarkable distinctions in the thermal stability, photocatalytic and photoelectrochemical properties.